Wikipedia:Reference desk/Computing

Welcome to the computing section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

July 26

latest version of IE

Why does the lastest version of IE not support Unicode in the bottom at the status bar and in the address bar too? Firefox can display proper characters instead of escape codes! Is it because the folks at Microsoft just can't be bothered? I mean, how much effort could it possibly take to do that???

Duomillia (talk) 01:00, 26 July 2009 (UTC)

No, you screwed something up on your system, not Microsoft. Unicode characters display great in my browser. For example, when I type this into the address bar, it loads fine: http://ουτοπία.δπθ.gr. But why are you asking us, anyway? Start a thread in a Microsoft Technet or Connect forum, if you're so sure that it's a bug. They're actually pretty good with fixing bugs if you make any kind of effort to contact them. By the way: In my experience, most people don't even know the status bar is there. The latest version of Internet Explorer is actually over-engineered in my opinion -- not the opposite.--WinRAR anodeeven (talk) 02:59, 26 July 2009 (UTC)

This is a deliberate feature intended to prevent phishing attacks. See IDN homograph attack. Internationalized domain names were not designed very well. Firefox also displayed decoded names in the address and status bars for a while. According to the article they now use a top-level domain whitelist. There's an IE option "always show encoded addresses", but I recommend you leave it off unless you use IDNs a lot. -- BenRG (talk) 11:03, 26 July 2009 (UTC)

J2EE programing

please suggest me a wonderful book or a good tutorial or website or anything which can teach me J2EE programming and HTML thoroughly...assuming that I have a basic knowledge of C,C++,JAVA.I am in great need to learn it.pl help —Preceding unsigned comment added by 117.193.128.204 (talk) 04:26, 26 July 2009 (UTC)

Java EE, like the rest of the Java technology platform, has no better resources than the Official Sun Java EE technology guide, including source code, example projects, tutorials, and all the software and tools you need to make a project. Download GlassFish and run the PetStore example application. You can find tutorials here: Java Pet Store. You can download all the tools here (check for your operating system and language version). Nimur (talk) 05:26, 26 July 2009 (UTC)

Regarding HTML, I use the W3 official specification as my preferred reference. If I were just starting out, I would try reading the HTML article on Wikipedia, which is a little more user-friendly. In general, HTML is best learned by viewing examples; once you have the basic tags, simply start viewing source for web pages you are browsing to take a peek under their hood. A lot of modern web pages use very complicated HTML combined with scripting and embedded plugins, so they can be intimidating source to read; but it's a good idea to get a feel for how the pages are put together. Nimur (talk) 05:32, 26 July 2009 (UTC)

Annoying Freeze

Every now and then I get sudden freezes. The computer completely locks-up. I cant move the mouse or use keyboard everything is frozen, you know what I mean. ALL i can do is restart pc. Another problem is desktop icons, start menu, images (also in internet image) gets broken into pieces and I can't see image properly. It looks like image gets scratched.

First I thought this was a cpu problem, then motherboard, then graphics card, then ram, hard drive etc. I just cant figure it out. It happens when I am on minefield, IE (latest version) firefox 3.5, when I am logging in at facebook. Even this problem persist after closing browser ! This was an issue before as well I don't know what is causing this freezes. If I play any music when I'm on browser the sound also gets crashed (screaming like carrrrr...). These are happening after upgrading my hardware. I am using XP SP 2. My processor is Core 2 Quad 9400 (which requires Vista 64 bit SP 1 though) and motherboard 750i SLI Nvidia Geforce, RAM 2 GB (800MHz), Sapphire ATI 4890 1 GB, Full tower Chassis (Tharmaltake Xaser VI). I have several XP SP 2 OS. The Current XP SP2 that I'm using, bought it 4 years ago.

How can I rectify this problem?--119.30.36.47 (talk) 14:36, 26 July 2009 (UTC)

The problem sounds like a hardware crash due to overheating. I would perform any available BIOS and/or graphics driver updates, then use a hardware monitoring tool like HWMonitor (there are various free ones) to track down the problem. Rjwilmsi 17:28, 26 July 2009 (UTC)

• But Sometimes I can move mouse for a while then it suddenly stopped again. You said"I would perform any available BIOS and/or graphics driver updates. My BIOS and graphics card are already updated (Correct me if I am mistaken). I have used HWMonitor. It shows only temperature after the crash. GPU Core is 61 *C to 63 *C. My full tower chassis has 5 collar fan (including two 140mm turbo fan) inside to provide sufficient airflow. What else I can do?--119.30.36.33 (talk) 18:17, 26 July 2009 (UTC)

63C is too hot. Try this - open your case and blow an ordinary room fan into the case to cool it down further. Your GPU should get below 50C... see if that helps. Either your case airflow is not optimal or helping the GPU, or there's something faulty with your graphics card. Sometimes these weird freezing/rebooting problems are due to the power supply which is faulty or dusty and your CPU is not receiving clean power from it. My last two PC problems were: playing video rebooting PC (replaced GPU) and random rebooting doing anything (replaced and upgraded power supply). Good luck. Sandman30s (talk) 09:55, 27 July 2009 (UTC)

• I forgot to mention that this freezing problem occurs only when I run my system for 8 to 12 hours or sometimes 5 hours.You said, "blow an ordinary room fan into the case to cool it down further". Are you suggesting me to add another GPU Cooling fan in additional slot (sorry for my English)? The chassis contains some extra slot for fans. One more thing is that my motherboard contains two GPU Slots. The First slot (where graphics card is attached) is located a bit above to turbo VGA cooling fan and does not get proper air. Second slot is closely located to the cooling fan and gets much air flow. I am thinking to remove Graphics card from first slot and attach it to second slot. I notified the hardware technicians (where I assembled my systems) about my intention but warned me not to do that as the second slot is for another graphics card and if the first slot does not work. They also suggested me to disable system restore point and schedule scanning of internet security to prevent this freezing state. Should I proceed to second slot? Suggestions ? --119.30.36.39 (talk) 13:32, 27 July 2009 (UTC)

Update: I have checked the BIOS. It shows CPU temperature is 30 to 31 *C and System temperature is 40 to 41*C.--119.30.36.42 (talk) 15:01, 27 July 2009 (UTC)

No, I mean: open the case. Take an ordinary electric powered fan that plugs into the wall socket. Plug it in. Turn it on. Face it towards your open case and your computer will get the benefit of cool air blowing directly onto the GPU's and everything else. This is a TEST. If it works, it means you have a heating problem and then you either need to swap your card/s or get better cooling in your case. Sandman30s (talk) 15:41, 27 July 2009 (UTC)

Ok. But is temperature from BIOS Ok or not. I should have mentioned that this freezing problem usually occurs when I am on online (after 12 pm) for 5 to 8 hours. Yesterday I run my system for 10 hours and nothing was happened. It seems that it only happens while I'm on online (I tested with all browser). I use Modem for net connection. If It's not overheating issue what else can it be? Is modem incompatible with system (which causes this freezing)? --119.30.36.53 (talk) 12:15, 28 July 2009 (UTC)

Windows 7 Torrent

I've been having a discussion with some friends and they don't believe that Windows 7 is already up on torrent sites (a full version) and I'm sure it must be. Though at the moment we're unable to access those sites ourselves. I was curious if someone could confirm whether it appears that full versions of Windows 7 are available to torrent. Of course, I wouldn't ask someone to link to them, just a confirmation that they themselves have seen it (and if you have used it, if it was for real). Thanks! 71.75.71.102 (talk) 14:47, 26 July 2009 (UTC)

Since even before the beta of Windows 7 became publicly available there have been versions of Windows 7 leaked to torrent sites. However, some of these leaked versions are known to have been tampered with or to contain malware and I would not recommend anyone try to download and use any of the leaked versions. Consider trying out the Release Candidate instead (Which expires June 1, 2010, with bi-hourly shutdowns beginning on March 1, 2010) or waiting for the final version of Windows 7 which you can pre-order now.--Xp54321 ^{(Hello! • Contribs)} 17:05, 26 July 2009 (UTC)

You could also use this[1] Mac Davis (talk) 00:45, 28 July 2009 (UTC)

Is this the end of my Nintendo DS?

As the title suggests, I'm worried that my DS going to become unplayable and I need some links or advice if the thing is on it's last legs or not. My problem is that when turning the DS on, it will be okay for a bit, then have some odd display problems (I can see something that looks like a brownish circuit board through the screens) I took out both of the games I was playing to see if they were the problem, but they weren't, the problem persisted even with both slots empty. If I plug in the headphones, the top display stops being wonky, but the bottom screen remains odd.

Another thing about the DS is that it got fried once by getting drenched by an exploding pop bottle, but when it dried out it worked just fine for a few months. Suddenly the speakers stopped working. I didn't really care, it worked fine with headphones plugged in so I left it and enjoyed it for no problems . Two days ago, the speakers suddenly began working again. And now today I'm getting these display problems. I'm not sure if the display and speaker problems could be linked, but it might explain why the display is okay on the top screen with the headphones plugged in.

So really, all I want to know is if my DS is doomed to die and I need to start looking for a new one. The display doesn't bug me that much, so if it'll be okay how it is and not die, I won't bother replacing it. Also, I can't really send it in for repairs because I have a feeling the pop explosion a year ago is what caused it. Also this DS is an original one (Not a Lite nor a DSi) and is about 4-5 years old now, it's warranty is probably gone by now. Thank you for your time. 69.157.106.254 (talk) 14:54, 26 July 2009 (UTC)

It is very likely that the circuits are corroding, and will die a slow death. Sorry. You could try cleaning its innards with distilled water or alcohol. (Do not use tap water.) That may help, but it would have helped more back when the accident first occured.

It's also possible that there is still soda on the board and it's causing intermittent short circuits. Again, that might be helped by cleaning it.

There is no way to know for sure, but either way I suspect that if you don't take it apart and clean it (No tap water!) it will slowly get worse. APL (talk) 17:54, 26 July 2009 (UTC)

Oh well. I wished I'd known about cleaning it when the whole thing happened a year ago. Thanks for your help. I'll give cleaning it a shot and start looking around for discounts for when the poor thing kicks the bucket. I'm just glad it managed this long, now with the DSi out, getting a DS will be cheaper. Thanks again! 69.157.106.254 (talk) 18:10, 26 July 2009 (UTC)

Resources for a beginning teenage programmer

I'd like to get my Nephew into development, probably with an ultimate goal of working in a MS or web environment (.NET I suppose?). He's a beginner so I guess the question is what's a good starting point or general introduction. Are there any interactive tools you can buy that can take you through lessons/labs? I don't know much about development but I'd be interested in something that's more focused on doing rather than reading...he's 14 so I'm nor sure how much time he'd spend sitting around just reading. Thought? Thanks...RxS (talk) 15:09, 26 July 2009 (UTC)

I'm 21, and I learned in Visual Basic around 14, but that's on the decline now. I'd recommend something like Java, and this is a tutorial I particularly enjoyed because it's more interactive. [2]. Hope that's useful. 71.75.71.102 (talk) 15:29, 26 July 2009 (UTC)

I'd suggest one of the Game engines, such as Game Maker. I've used them with teenagers before, and they have the advantage of being interesting to program in quickly. While the language isn't much use itself, the principles are. Alice is a good beginner's language as well, with quick rewards, but I'm not sure if it has a clear path for where to go once you get the hang of it. It does have nice tutorials, though. For serious languages, I'd go straight to C# or Java. I'd add that the main aim is to keep it interesting from early on, and part of that is making the projects interesting. - Bilby (talk) 15:44, 26 July 2009 (UTC)

That's what I'm mainly interested in, fairly quick engagement/visible results that provide a good foundation and path to more advanced concepts in current technology. Thanks! RxS (talk) 15:54, 26 July 2009 (UTC)

It sounds like Java is a good starting point, are there any other resources available? The one linked above seems to give Vista/IE 7 fits. Thanks again...RxS (talk) 17:05, 26 July 2009 (UTC)

http://math.hws.edu/javanotes/c3/index.html this link causing problems - I'm on IE7 and it seems to work perfectly.? Seems such an innocuous site.

Resources for learning java? - sun has one - tutorials, plus lots of documentation - just search for "sun java", and you should find it. I believe they have a 'young programmers' section or program as well. Here's a start page http://java.sun.com/new2java/learning/young_developers.jsp Possibly the first few sections are aimed at younger children.83.100.250.79 (talk) 22:10, 26 July 2009 (UTC)

If they have no programming experience before I would probably recommend something else - probably python (programming language) (since everyone else does) - it's pretty much the equivalent of what BASIC was 20 years ago - it's easier to get into for a first language (yet it's still a proper language - with real world uses). Though it might be just as good to start in a slightly harder language straight away - I certainly found it hard going from 'beginners or educational' languages to 'proper languages' - the easy ones can cause laziness.83.100.250.79 (talk) 21:25, 26 July 2009 (UTC)

Most Universities (in US/Canada) seem to start off with Java, as did my high school; it really wasn't too bad as a starting language. As far as visible results go, Robocode is pretty fun. -- Consumed Crustacean (talk) 01:16, 27 July 2009 (UTC)

I'd like to recommend Robocode as well - it's a good system for learning some prinicples fast. I recommend it to the first years as something for them to practice with. Just keep in mind that Java itself requires a fair bit of theory before you can code anything of value. The language is very nice, but unless you use something like NetBeans the GUI can be complex to learn, and the OO side of things is tricky. Which, of course, is part of why we teach it. :) I normally recommend BlueJ as a first IDE, but that's mostly because of its educational value, so it might not be useful at home. - Bilby (talk) 01:29, 27 July 2009 (UTC)

Parallel Port Programming

I would like to know what a parallel port programming is and how to use it in programming of microcontrollers.i.e.in robotics.Pl suggest some good ebook or website where I can get all the info on this. —Preceding unsigned comment added by Gd iitm (talk • contribs) 16:43, 26 July 2009 (UTC)

Perhaps this web site can help. 91.32.118.182 (talk) 18:13, 26 July 2009 (UTC)

See the article Parallel port. But note that manufacturers have stopped providing parallel ports on their PCs. Cuddlyable3 (talk) 21:14, 27 July 2009 (UTC)

Equivalents of pointers and/or dereferencing in scheme ?

I'm doing things like this:

> (define a 10)  
:ok
> a
:10
> (define b '(1 a 2))
:ok
> b
:(1 a 2)
> (cadr b)
:a

Basically I can't work how to make the "a" in (1 a 2) act as a variable, and by extension how to control whether it's evaluated, or left as "a" e.g. Are there commands to do stuff like this in scheme? e.g.:

> (define a 10)
> (pointer a)  ie the command I'm looking for
:a
> (dereference (cadr '(1 a 2)))  the other command I'm looking for
:10

?I must be conceptualising the whole language wrong I suspect?83.100.250.79 (talk) 19:31, 26 July 2009 (UTC)

I think what you're looking for is quasiquote and unquote:

1:=> (define a 10)
a
1:=> (define b `(1 ,a 2)) ; equivalent to (define b (quasiquote (1 (unquote a) 2)))
b
1:=> b
(1 10 2)
1:=> (cadr b)
10

24.76.174.152 (talk) 20:10, 26 July 2009 (UTC)

Nearly (or possibly) - however if I do

> (define a 99)
> (define b `a)
> b
a

Which is better than before (ie not 99)

But how do I get

> (func b)
99        and not a

That step eludes me (I was trying force and delay before as well - with not total success).83.100.250.79 (talk) 20:52, 26 July 2009 (UTC)

If you write (quote a) then you get a quoted symbol a, which has nothing to do with any variable named a in the environment—it's like the string "a" in other languages. (Modern Scheme also has strings, but earlier versions just had symbols doing double duty.) If you write (quasiquote a) then you get the same thing because quasiquote quotes everything that isn't wrapped in unquote. You could write (quasiquote (unquote a)), but that's the same as just a.

If you want to update a and have b reflect those changes "on the fly" then that can't be done directly—there's no way to make a data structure incorporate the current contents of a variable by reference. Variables (like a and b) point to objects (like numbers and pairs), and some objects (like pairs) can point to other objects, but objects can't point to variables. This is similar to Java, where you can only have references to heap objects, but different from C++, where you can also have pointers to variables and object fields. But you could write a function that makes the appropriate change to both a and the corresponding part of b explicitly:

         (define (change-a! new-value)
           (set! a new-value)
           (set-car! (cdr b) new-value))

-- BenRG (talk) 20:59, 26 July 2009 (UTC)

Thanks, Yes it's exactly the type of thing you describe in the second paragraph that I'm trying to do (though I read that set-car! is to be 'banished' in v.6 scheme)

Maybe I'm using the wrong tool - I'm looking for a language with strong support for nested lists (ie like lisp or scheme), but with pointers to objects as well (the easy way) - does such a thing exist?83.100.250.79 (talk) 21:10, 26 July 2009 (UTC)

But every value in Scheme is already a pointer. (It's like Python.) That's why you can do stuff like this

         (define a (car 1 2))
         (define b a)
         (set-car! a 3)
         (car b) ; evaluates to 3

--Spoon! (talk) 07:15, 27 July 2009 (UTC)

As Spoon said, if a refers to a pair and you incorporate a into b, then change the members of the pair, that change will show up in b. But you can't do that with numbers like 10 (they are immutable) and you can't replace the whole pair "in place" with a number or vice versa—you have to do two assignments to the two pointers that reference the pair in that case. People often solve this kind of indirection problem with extra levels of indirection. A common trick in Scheme is to create a pair with a dummy symbol in the car (like '*my-mutable-thing*) and the payload in the cdr. That does require extra indirection when reading, though. Even in C++ you can't indirect via a variable without an extra * when reading.

ML is a Scheme-like language (it shares the emphasis on lists and recursion) that handles mutation in a cleaner way than most other languages. It avoids all these funny rules about variables versus objects versus parts of objects, but it may not be more convenient in practice if you already understand those rules. You could also look at dataflow programming. In dataflow languages, when a changes, not only does b automatically change but also any other computation whose value depended on a. For example if you had written (define c (+ a 10)) then incrementing a would also increment c. The DrScheme system includes a dataflow extension called FrTime. But hardly anybody uses dataflow languages, so if you need the support and future-proofing that you would get from a mainstream language then you probably can't use dataflow. If you give details on what you're trying to do we could probably give better suggestions. -- BenRG (talk) 09:06, 27 July 2009 (UTC)

(edit) I'm going to have a look a FrTime, and see what it does83.100.250.79 (talk) 12:03, 27 July 2009 (UTC)

(edit) It sounds like FrTime does too much - it sounds like it re-evaluates the whole data structure when a field changes - I just want it to evaluate what is necessary for an imperative instruction.83.100.250.79 (talk) 12:08, 27 July 2009 (UTC)

Thanks, your description of dataflow programming sounds like what I was thinking about.

Basically I was just exploring the features of programming languages without any particular application in mind.

Specifically if a is a variable I would have been incorporating it into many different lists - so the scheme method listed above by BenRG wouldn't really be suitable. - I wouldn't be able to (or expect to) keep track of all the instances of a. So the equivalent of a pointer data type would have been the way to go - However I only needed the data to update on imperative resolution eg not sure if this is the same as 'dataflow'.

I was also hoping to mix functions and data in a list in a similar fashion - but noticed that if a function returns differently sized or structured lists then this could really mess up the whole thing - requiring functions to be run (with the wrong state information) just to attempt to get the size of the list. eg if a=(0 fn(x) a ) and fn(x) can return 0 or 1 or (0 1 2) or even +{0 1 2}+ ie inserted flat into the list, not nested then I can't find/think of a solution for that as yet. I could probably implement the list with pointers myself though.83.100.250.79 (talk) 11:21, 27 July 2009 (UTC)

I was just reading what Spoon! said - it looks like I didn't understand the data structure - I was expecting everything to be a pointer (as they say)- the language has to be intrinsically 'pointy' for those lists.

What I don't get is why Spoon!s example works, but when I just do (define a 10) , (define b a) , (define a 20) ; b gives 10 ie it immediately dereferences b and a, but when using a pair it does something different. Is there an exaplanation for this apart from 'that's the way it was designed' (Isn't 10 a list too, with the second field null?) 83.100.250.79 (talk) 11:31, 27 July 2009 (UTC)

10 is not a list. In C++ terms, all variables have type Object*, numbers look like

       struct Number : Object {
           const int value;  // or double or complex or ... full numeric tower
       };

pairs look like

       struct Pair : Object {
           Object* car;
           Object* cdr;
       };

and the empty list is like the null pointer. So when you write (define a 1) (define b a) (set! a 2) it's like

       Object* a = ONE;  // where ONE is a global that points to a Number with value 1
       Object* b = a;
       a = TWO;

which doesn't change b. But when you write (define a '(1 2)) (define b a) (set-car! (cdr a) 3) it's like

       Object* a = new Pair(ONE, new Pair(TWO, NULL));
       Object* b = a;
       a->cdr->car = THREE;

which leaves b->cdr->car also equal to 3. (Note that you shouldn't use define to change the value of an already-defined variable, though it's supported. You should use set! for that.) If I understand you correctly, the problem you're having would also exist in C++. If a is a pointer and you incorporate that pointer into a bunch of data structures, changing a won't change the data structures—you would have to track them all down and update them individually. -- BenRG (talk) 15:53, 27 July 2009 (UTC)

(First Note: you shouldn't use define on a variable twice in the same scope. Use set! to assign to a defined variable.) set! only changes where a pointer is pointing to. It does not affect the thing that is pointed to. So when you do (set! a 20), it just redirects the pointer to point to another number object. Whether you can modify an object pointed depends on the type of object. There is no mechanism to modify a number object (i.e. they say it is immutable). However, there is a way to modify pair objects, with set-car! and set-cdr!. That's why you can modify a pair object and be able to see the changes through another pointer that points to the same pair object. --Spoon! (talk) 19:49, 27 July 2009 (UTC)

Thanks for your responses - I've found something that almost does what I want :

(define a 200)
(define b (lambda() a))
(b)
result 200
(define a 300)
(b)
result 300

this always evaluates to the current value of a, which is good, but I have to bracket b to get the number, if anyone can suggest a better way, please, as I'm still working out if I can utilise this method easily.83.100.250.79 (talk) 15:15, 27 July 2009 (UTC)

I was going to suggest that, but I'm not sure it's really what you want. -- BenRG (talk) 15:53, 27 July 2009 (UTC)

You shouldn't define something twice. Use (set! a 300). --Spoon! (talk) 19:44, 27 July 2009 (UTC)

Another mystyfying thing about scheme

As mentioned above I was trying things like (define a 10) , (define b a) , and (cadr (1 a 3)) - now in the first two examples it treats a as a variable, whereas in the third it seems to just think a is "a" ie text. How does it decide? And does ML (mentioned above) or another language (in the family) support a more explicit of distinguishing variables and text?

I know this is very similar to sticking beans up my nose as a hobby , but if anyone end my curiousity I would thank them. :) 83.100.250.79 (talk) 11:47, 27 July 2009 (UTC)

(cadr (1 a 3)) is an error—it attempts to call the number 1 as a function. You mean (cadr '(1 a 3)). That gives you a quoted a because quote (') quotes everything underneath it in the expression tree. define is a so-called special form (as is quote). It's magical and can't be implemented as a Scheme function. You should read a Scheme tutorial, which will explain all of these things better.

In ML everything is read-only except for refs. A ref lives on the heap and holds a value that you can get or set. Instead of a mutable variable you use a constant variable that refers to a ref on the heap. This means that every mention of a variable is a mention of its value, not a reference to its location, so you don't need a special form like set!. If you incorporate the variable's value into a data structure then the data structure refers to the same ref and setting it will affect the data structure too. You could get the same effect in Scheme by defining

        (define (make-ref val) (cons '*ref* val))
        (define ref-get cdr)
        (define ref-set! set-cdr!)

and then never using any mutation functions other than ref-set!. -- BenRG (talk) 15:53, 27 July 2009 (UTC)

Thanks, (yes I missed the ' ) - I think my exectations may have been wrong - I read that scheme/lisp stores program/data in the same form and that a program was a list too - from this I inferred (wrongly) that lists created by the program could contain executable programs as well ('out of the box' so to speak).

I have been reading scheme tutorials (possibly not very good ones - they didn't explain that '(+ 1 2) destroys all type formatting and renders function names as text)- I suppose the reason they didn't have the answer was that what I was looking for didn't exist - oh well!. So there's not a way to force an evaluation on a list eg

(try-this-list-as-a-program '(+ 1 2) ) 

83.100.250.79 (talk) 16:29, 27 July 2009 (UTC)

because + has been convereted forever to a char, and can't be got back into a proceedure type. —Preceding unsigned comment added by 83.100.250.79 (talk) 17:16, 27 July 2009 (UTC)

There is eval in R⁵RS Scheme:

    (eval '(+ 1 2))

:-) --Spoon! (talk) 19:37, 27 July 2009 (UTC)

Cool. (I did try eval on the off chance - but it didn't quite work..)

I'm using "DrScheme" R5RS and eval doesn't work - gives the curious error message "procedure meval: expects 2 arguments, given 1: (+ 1 2)" (yes it spells eval wrong as well), must be a bug. Curiously in MrEd (same distribution) eval works as planned. Anyone familiar with PLT Scheme and know what's going on? 83.100.250.79 (talk) 20:21, 27 July 2009 (UTC)

Here's the spec. eval takes two arguments, an expression and an environment. There's no standard way to get the current environment (it would require a special form because of lexical scoping). Supposing a (current-environment) special form exists in your Scheme, (eval 'a (current-environment)) does the same thing as a but is very inefficient. Storing an expression in a data structure and then evaling it does the same thing as putting it in a (lambda () ...) and then calling it, except that it's much slower, less convenient to call, and violates lexical scoping (because it will see the variables at the call point instead of the variables at the definition point). There's no reason to use it. Code and data are not the same in Scheme, they just look alike because they have the same syntax (s-expressions). -- BenRG (talk) 08:58, 28 July 2009 (UTC)

Yes thanks, I got the feeling it was the same as going through the command line interpreter ie it has to convert what is effectively an ascii string to whatever code scheme uses. I wan't to avoid that.

I think I'm getting it to do what I want now :eg

(define a (lambda () '(1 2 3)))
(define b (lambda () (cons 4 (cons (a) 6))))

Which makes the 'a' in function b act like a pointer to the function 'a', and 'b' changes with a. this is the reason I was originally interested - because I got the impression scheme/lisp could do thinks like this easily - thank god it does :)

I'm just trying to work out the difference between '(4 (a) 6) and (cons 4 (cons (a) '(6) )corrected once - initially I got the impression that the structures created by both were the same ,with (list 1 2 3 etc) just being a shorthand avoiding doing a lot of cons.

Also does anyone know what I type in for 'null' - it rejects null , nil, ()

I can't find it in the manual except what seems to be a suggestion that typing "null" should work found it '() 83.100.250.79 (talk) 10:45, 28 July 2009 (UTC)

I'm glad you found something that works. Writing (define a (lambda () '(1 2 3))) and (a) is slightly different from writing (define a '(1 2 3)) and a because the former conses together a new list every time you call it, which matters if you use set-cdr! and the like—but maybe you don't need those any more. Everything in '(4 (a) 6) is quoted, including the (a), whereas in (cons 4 (cons (a) '(6))) the (a) is unquoted so it's a function call. The 4 is also unquoted but it doesn't matter because it evaluates to itself. -- BenRG (talk) 22:41, 28 July 2009 (UTC)

Resolved

OK thanks for your help , and your patience. I think I can call this resolved, the engine starts, and I've stopped putting sand in the tank unless somebody notices that I'm doing things the wrong way, or knows a more sophisticated solution.. In which case please say. Thanks again.

This isn't so much an answer as a further question, but nonetheless: does Scheme really not have symbol-value or any equivalent? I guess that it sort of makes sense, since it has only lexical scoping and no use of a appears lexically in (symbol-value 'a). But if eval exists (even if it's crippled by the lack of a standard current-environment special form), it seems silly not to also provide this simplest part of what it does (resolve symbols into variables). --Tardis (talk) 21:49, 28 July 2009 (UTC)

Scheme symbols (unlike Common Lisp symbols) don't have values. They're just like C identifiers. All variable references are lexical and hence are supposed to be unaffected by alpha renaming. You could write a value-at-top-level that used eval, but it would be a weird thing to standardize because it's not something you really want to encourage. Lexical scoping and eval interact badly. Aside from the theoretical issue (alpha renaming), you have to maintain a bunch of metadata at runtime that wouldn't otherwise be necessary and you have to inhibit various compiler optimizations because you can't predict at compile time what variables will be read or written by the eval. It's basically the same problem as doing it in C. I'm somewhat surprised they included eval at all. -- BenRG (talk) 22:41, 28 July 2009 (UTC)

How can I extract individual images from video-slideshow?

I have a video-slideshow created by Photo Story 3 using the Windows Media Video 9.1 Image v2 codec. How can I extract the static images from this file? --Me (talk) 20:01, 26 July 2009 (UTC)

Perhaps the Gom player could do it. 78.144.197.8 (talk) 17:00, 30 July 2009 (UTC)

Elevator logic control

Hi there, I'm in the process of creating an app/game/sim/whatever you want to call it that emulates a lift (elevator). I've got the thing working pretty well but am stumped at getting the logic right for handling calls. (Originally asked this on the science desk but this is probably a better place to ask it.)

At the moment, there are two objects: DRUp and DRDown that both contain a variable which can be set to 0 or 1 (0=off, 1=on), this simulates a pair of switches that control the direction. The lift operates a 'mechanical' floor selector (a moving object that triggers events when it touches other objects) that makes contact with various switches to tell the lift where abouts in the shaft it is. When the top floor and bottom floor switches are triggered, it toggles the direction switches so if it's at the top floor then DRUp=0 and DRDown=1, because the lift cannot go up from the top floor! The ground floor switch does the opposite.

This works fine for going in the same direction, however if the lift car is on the ground floor and I am on the second floor and want to go to the ground floor, the lift goes all the way to the top, reverses direction and then stops at the second floor. I need a way of resetting the direction switches from other floors but ONLY if there are no further calls in the original direction.

Example: Lift on ground floor Call from 2nd floor Lift goes UP to second floor Are there any more calls going UP? If yes, continue up, if no, reverse direction.

I can probably do it a long-winded way by setting up a long and protracted if statement along the lines of:

If Floor=1 and LR2Up and LR3Up and CR2 and CR3 and CR4 = 0 then DRUp=0 and DRDown=1 (LR being landing call switches and CR being lift car call switches)

However I'm sure there must be a simpler way of doing it (probably something to do with the floor selector). I can't see how old-fashioned lifts with relay logic could evaluate complex if statements. I think from looking at old and very complex documents about electromechanical lift controllers, the floor selector has three parts on top of each other that tell it which way to go but not sure).

Anyway, if you're interested, I've put the project so far online: http://www.arthurflowers.co.uk/games/Lift2_1.exe , any comments would be good.

Thanks in advance for any information. GaryReggae (talk) 21:44, 26 July 2009 (UTC) —Preceding unsigned comment added by GaryReggae (talk • contribs)

May I suggest that you re-ask this question on the computing ref desk - you'll get a much better answer there. SteveBaker (talk) 21:55, 26 July 2009 (UTC)

It was not clear to me whether your lift has a single call button at each floor, or two buttons for a user to call to go up or down. There may be security problems about your link to an executable. Consider showing pseudocode instead. Cuddlyable3 (talk) 22:20, 26 July 2009 (UTC)

Thanks - I have posted this on the Computing desk too. I only posted it here in the hope that somebody that knows about electronics and engineering might know how these things work in the real world. I have been looking on Google patents about old lift controllers and it seems that the floor selector has three parts that control the direction but it's all incredibly technical and goes into too much detail.

The lift has two buttons on each floor, each one activates either an up call request switch (LRUp or a down call request switch (LRDown). Buttons pressed in the lift car itself activate a third switch for each floor (CR). At the moment, the lift will answer all the calls going down then all the calls going up but as I said, the lift currently travels to the top and bottom floors to change direction, so if I were to only want to go between two of the middle floors, I would have to go all the way and then back.

I don't know how to do pseudocode but I will try blockquoting the link:

http://www.arthurflowers.co.uk/games/Lift2_1.exe

GaryReggae (talk) 22:29, 26 July 2009 (UTC)

There are many articles that contain examples of pseudocode. Loading executables from the Internet is forbidden in many computer environments e.g. school networks, because of the potential for virus attack. Cuddlyable3 (talk) 22:58, 26 July 2009 (UTC)

--- end of answers from Science Desk ---

minor point (Did you realise that by directly linking to the file you have allowed users to circumvent your draconian user aggreement? eg http://www.arthurflowers.co.uk/ ?) —Preceding unsigned comment added by 83.100.250.79 (talk) 22:55, 26 July 2009 (UTC)

What language? (may help in the answers)

Another thing I have to ask is "can there be multiple people requesting the lift" - it's a lot simple if only one person uses the lift at once.

Basically don't you need two variables "LiftFloorRequest" and "LiftFloorRequestDestination" - first the lift goes to "LiftFloorRequest", then it can contine (or change direction) to go to "LiftFloorRequestDestination". You could add an additional flag for "LiftMode" - which would be either "seeking customer" or "delivering customer" which might help keep things clear.

(If more than one person is using the lift then I think real world practice is for the lift to go up to the highest request, and down to the lowest request - ie when more than one button is pressed the lift reverts to the mode you already have - ie straight up and then down.)

Also it's probably more use if you can link to the program code, rather than the program - otherwise we won't really know how you are doing it.)83.100.250.79 (talk) 22:36, 26 July 2009 (UTC)

In terms of the actual electrics, rather than a simulation - I'd guess that there would have to be a wire for each level if you want to go to the highest selected level rather than the top - though it's possible to do it with only a couple of wires. I'm no lift expert - it's not clear if you're trying to simulated the original mechanism or just making an lift program that works.

(Actually I think I can describe a very simple relay circuit for what you are describing - which would convert into two program variables - the self explanatory "HighestButtonPressed", and "LowestButtonPressed" - it's probably clear from those words that all you need to do is work out the two values, and let the lift oscillate between the two. (I imagine there are many implementations)83.100.250.79 (talk) 22:42, 26 July 2009 (UTC)

Yeah, I'm trying to simulate the original mechanism as far as is possible. There is only one person calling the lift at any time. I can't put the code in as I have built this thing using 'GameMaker', a GUI that allows you to create games. You can use variables, as indeed I have but each 'object' has its own set of 'events', such as MouseClick and Step (runs the same procedure constantly). I have an object that controls the motion of the lift car - if there are no calls then it exits the event, if there are calls then it moves the lift car in whichever direction is specified by the direction switches DRUp and DRDown. The DR switches are toggled when the 'mechanical' floor selector touches the ground or top floor switches.

Here is a screenshot: http://img188.imageshack.us/i/atflift2.jpg/

With regard to the draconian user agreement, yeah, I put it there out of sarcasm after I got in trouble at work for posting technical stuff on that website but it was nothing to do with them really.

GaryReggae (talk) 22:56, 26 July 2009 (UTC)

This doesn't address your specific issue, but you might be interested in looking at SimTower. This game evolved from an earlier elevator simulator and ended up being fairly commercially successful. Nimur (talk) 23:04, 26 July 2009 (UTC)

I'm not sure that I can help you much more, but I think I can explain how the relays simulate the logic if you need that (you mentioned above that you didn't see the connection) - if there are two wires coming from the top, one 'power', and one 'signal' - then pressing the button on a floor will connect power to signal by activating a relay. By doing this power is routed to the signal wire (going down) - thus the power wire below this floor is now not connected... The relays on each floor have to be set up so that the signal cannot go upwards at the point were power is routed to signal. (probably a double throw relay) this has 3 effects:

• thus the signal wire is only live below the highest floor on which a button has been pressed.
• power wire is disconnected on floors below. (therefor pressing the button does nothing)
• pressing a button higher up still works

(If the power is off then the switching relays need to reset themselves.)

Combine this with the same mechanism going upwards instead of downwards (another 2 wires plus 'ground')

The lift only runs where both the signal wires are live - additionally losing one of the signal wire connection means the lift needs to change direction - this can be acchieved with relays too. ie connect the two signal wire feeds to another relay - if one is absent the relay will switch (in one of 2 directiosn)- which in turn can be used to switch the motor power.

Obviously getting the lift to stop exactly at the floor makes this more difficult.

I think it would be quite possible to emulated this in your program if you haven't already - ie you could have close up images of the relays switching, or mabybe even colour the wires where they are live.83.100.250.79 (talk) 23:21, 26 July 2009 (UTC)

By the way I think the technical term is Interlocking - but all that article is about trains and not lifts - though a lot of the principles are the same.83.100.250.79 (talk) 23:24, 26 July 2009 (UTC)

Elevator Logic

The number of floors in the building is Nf.
The following are independent on/off states. Each could be a latching relay (relay controller), a set/reset latch (logic
controller with MSI chips or FPGA), 

or one-bit flags in memory (µP controller).

- For each floor i = [1...Nf] there are 3 state bits:
  Cdi = Call to descend
  Cai = Call to ascend
  Di  = Directed to floor
  Cdi and Cai are set by pushbutton call switches at each floor. Cdi and Cai illuminate their respective call button so
the caller gets immediate confirmation.
  Di are set by pushbuttons inside the elevator and illuminate their respective buttons so riders get immediate confirmation.
  
- For the elevator there are state bits:
  Kdi = Commit to descend from floor #i
  Kai = Commit to ascend from floor #i
  (Kdi AND Cdi) and (Kai AND Cai) are AND functions that illuminate arrows at the respective elevator doors. These give
further confirmation to a caller that s/he will soon be served, and they show which of Cdi/Cai will be answered first
when both call buttons have been pressed. A "ping" sound is given at the floor when either arrow lights.

The elevator logic monitors the location of the elevator f = [1...Nf]. This can be done in various ways such as by a rotary
optical encoder in the lifting gear, or interlocking microswitches at each floor. It could be done using a momentary
contact switch at each floor thus: as the elevator touches each switch the controller increments or decrements a floor
counter, depending on whether the elevator is ascending or descending. Floor #1 has an extra contact switch that keeps
the floor counter synchronised to the actual floor numbers. Number f is displayed to riders inside the elevator.

Initialisation at switch on and after a power break:
 All (5 x Nf) - 2* state bits reset.
 Bring elevator to f = 1 (ground floor) to synchronise floor counter.
 Self test routine (in µP) may include testing all lamps.


The elevator logic executes the following.
-----------------------------------------
SCAN UP CALLS
Pa = 0  pending ascend flag 
for i = f to Nf
 Kai = Cai OR Di
 if Kai=1 and Pa=0 then fd = i  destination floor 
 Pa = 1
next i
if Pa=0 goto SCAN DOWN CALLS

while f<fd raise elevator
(At floor fd) Open doors, Caf = 0, Kaf = 0, Df = 0
(After delay 5 seconds) Close doors. If door is blocked, open and repeat.

goto SCAN UP CALLS

SCAN DOWN CALLS
Pd = 0  pending descend flag
for i = f to 1 step -1
 Kdi = Cdi OR Di
 if Kdi=1 and Pd=0 then fd = i  destination floor
 Pd = 1
next i
if Pd=0 goto SCAN UP CALLS

while f>fd raise elevator
(At floor fd) Open doors, Caf = 0, Kaf = 0, Df = 0
(After delay 5 seconds) Close doors. If door is blocked, open and repeat.

goto SCAN DOWN CALLS
-----------------------------------------

Notes on this simple elevator implementation: 
1. When no one uses the elevator the controller alternates between SCAN UP CALLS and SCAN DOWN CALLS. That is innocous
for a µP controller but would be unwelcome activity in a relay controller.
2. Calls are not served well while the elevator is in motion. It is possible for the elevator to proceed past a floor
if a call to that floor was made after the elevator starts. That will distress a rider who changes their mind during
travel.
3. No provision was made for soft acceleration/deceleration so the elevator speed is limited.

Possible improvements which are more suitable for tall buildings:
Re. 1. When Pa = Pd = 0 the elevator could be sent to an optimum rest floor, such as ground floor or a mid floor.
Re. 2. Response to rider controls could be improved by scanning Di's more often than only when the elevator stops.
Re. 3. Higher speed without abrupt starts/stops is possible if full speed/stop is reached only after travelling one floor.
However for that strategy one cannot respond while the elevator is in motion to a new Di (in 2. above) nor commit to a new
Cdi/Cai where i is closer than f +/- 1. Travel from a floor to an adjacent floor can only reach half the maximum speed.

Overload, Fast Mode
The elevator car should have a load sensor.
- EXCESS load causes the doors to stay open, prevents elevator movement and (preferably) shows a warning to occupants.
The following improvements to load sensing are possible.
- FULL load corresponds to maximum number of adult occupants. Ignore floor calls and obey only occupant directions Di.
This avoids serving floor calls with a full elevator that the caller cannot enter.
- EMPTY load corresponds to less than the weight of a child. Move elevator at maximum speed with abrupt start and stop.

*On floor #1 there is no Cd1 button nor down arrow. On floor Nf there is no CaNf button nor up arrow.  

Cuddlyable3 (talk) 21:04, 27 July 2009 (UTC)

July 27

AI database

10 or 15 years ago (I think), there was a project to get volunteers to input common knowledge into a database for an AI program to use (things like apple ISA edible fruit). Does anybody know what happened to it? Clarityfiend (talk) 04:12, 27 July 2009 (UTC)

It sounds like you're talking about a Commonsense knowledge base. There's several famous ones listed on that page. The one closest to your description is Open Mind Common Sense, I think. Indeterminate (talk) 05:07, 27 July 2009 (UTC)

I think it was Cyc; the name rings a bell. Thanks. Clarityfiend (talk) 06:11, 27 July 2009 (UTC)

Python "for x in y" operator overload

When I use if x in y: (expecting a boolean to be returned), the real operator being called is __contains__ (so that x.__contains__(y) is the same as y in x). But apparently, when I use for x in y: it's something different. It's not even mentioned in help(list). Here's some sample code I wrought up:

class x:
    def __init__(self):
        self.data = [1,2,3,4,6,5,7]
    def __contains__(self,con):
        return con in self.data

## Now, testing it:

if 4 in d:
    print(4)    ## good - it returns 4
if 26 in d:
    print(4)    ## good - it doesn't return 4
for x in d:
    print(x)    ## bad - it gives "TypeError: 'x' object is not iterable"

Anybody know what the underlying operator is? Thanks, [flaminglawyer] 04:24, 27 July 2009 (UTC)

You're looking for the iterator protocol. For example:

class Uppercaser(object):
    def __init__(self, strings):
        self._strings = strings

    def __iter__(self):
        for string in self._strings:
            yield string.upper()

In usage:

>>> for s in Uppercaser(['Foo', 'bAr', 'baZ']):
...     print(s)
... 
FOO
BAR
BAZ

You can easily implement __iter__ using a generator. You can also implement __getitem__ and __len__ instead, but iterators are generally a nicer solution. 24.76.174.152 (talk) 05:18, 27 July 2009 (UTC)

Wow. Your explanation is really straigtforward... But the docs page... I'll have to look into this new "iterator" thing. Thanks :) [flaminglawyer] 05:46, 27 July 2009 (UTC)

Download albums from Shutterfly?

Hi. My friend has several albums on Shutterfly of an activity that I was in too, and I want to download the pictures onto my computer (hi resolution if possible). I know Shutterfly probably doesn't want you to do this (as they won't make ad money if you don't use their site to access the pictures), but I was wondering if someone has made a free tool to do it. I clicked on one image and it gave me an option to download that image after I sign in (I don't know if this is a limited thing or if it will work for every picture). However, there doesn't seem to be a way to download the entire album. The albums have like 700 pictures in them so manually going through each picture is not feasible. Thanks, --76.91.63.71 (talk) 10:25, 27 July 2009 (UTC)

Your friend uploaded the images to shutterfly so why not get the images directly from your friend? If the images are not huge (<6MB), each album should easily fit on one DVD-R. Astronaut (talk) 23:31, 27 July 2009 (UTC)

Bellinis Bikini

I can't get any further, please help me complete the fucking game .. It's soo hard!! (: I can't find any light, so I can go into the cave, and how do we move on? Please help we are desperate!!!!

• 0*
• Please do not use any slang word ! I suggest you to go to games forum for further assistance for this game.--NAHID 13:42, 27 July 2009 (UTC)

... or you could try posting this on the entertainment desk. They're generally better with video games. [flaminglawyer] 22:44, 27 July 2009 (UTC)

What is window vista ultimate??

can anyone give me a description and the general purpose of the window vista ultimate?? i will wait for your reply.... wish to see your reply soon... thank you ^^ —Preceding unsigned comment added by Bebezaii (talk • contribs) 13:49, 27 July 2009 (UTC)

See Windows Vista editions#Windows Vista Ultimate. PrimeHunter (talk) 13:53, 27 July 2009 (UTC)

(e/c) See our article on Windows Vista editions. Basically it's Home Premium (the best version for regular home users) and Enterprise (for large businesses) combined with a few extra features added on. It requires a really really high-end computer if I remember correctly. If you're thinking of buying it, then you should probably wait for Windows 7 Ultimate to be released this October. Xenon54 (talk) 13:55, 27 July 2009 (UTC)

No, I can't think of any features in Ultimate that require "a really really high-end computer". Windows Aero is the Vista component (optional to use) which has the highest system requirements, and it isn't specific to Ultimate. Tempshill (talk) 14:53, 27 July 2009 (UTC)

The answers can be got 'from the horses mouth' as well - http://www.microsoft.com/windows/windows-vista/compare-editions/default.aspx - to summarise 'ultimate' is the business ready version of vista with the media features of the home premium version.83.100.250.79 (talk) 15:19, 27 July 2009 (UTC)

Bitdefender Rescue cd

How do I use this file BitDefenderRescueCD_v2.0.0_27_07_2009.iso.md5, MD5 check program accept it. Also how should I verify the checksum of BitDefenderRescueCD_v2.0.0_27_07_2009.iso. yousaf465'

I got the checksum of download file as "1813A52837CC06E7C2EB25A416FBE84E". yousaf465'

The purpose of the checksum is to make sure that the large .iso file downloaded with no errors. You should take the md5 of the ISO file. Then, compare it to the expected MD5 in the the small text-file. If the computed hash matches the pre-computed hash, then we can say with a high degree of certainty that you have the correct .iso file. This is an effective way to assuage paranoia about download errors or intentionally modified binary files, but it is not a required part of the process to burn a CD. Nimur (talk) 15:33, 27 July 2009 (UTC)

BitDefenderRescueCD_v2.0.0_27_07_2009.iso.md5 is not a text file, how could i check md5, the above Md5 checkesum is for BitDefenderRescueCD_v2.0.0_27_07_2009.iso.yousaf465'

 Done I open the md5 file with notepad it gave "1813a52837cc06e7c2eb25a416fbe84e BitDefenderRescueCD_v2.0.0_22_07_2009.iso

" I think this file is correct. Will check with a md5checksum program.yousaf465'

seeking identification of an icon

Does anyone know what program this icon is from?—msh210℠ 17:03, 27 July 2009 (UTC)

I don't know but maybe if you crop it you can run it through tineye-- penubag  (talk) 18:31, 27 July 2009 (UTC)

What happens if you hover the mouse over it, or click on it (left or right)? Astronaut (talk) 23:24, 27 July 2009 (UTC)

No, the image is too small. You could try interpolating/scaling it but I don't know if that will help, I suspect TinEye just doesn't do that sort of thing Nil Einne (talk) 23:50, 27 July 2009 (UTC)

Windows/Mac comparison

Are there any advantages of Macs over Windows and vice versa (From a general perspective)? Chevymontecarlo (talk) 17:24, 27 July 2009 (UTC)

http://www.xvsxp.com/finalscore/ 87.113.158.164 (talk) 17:44, 27 July 2009 (UTC)

Something I found lacking in this is that while where was a "games" category, it only talked about games that game with the OS (minesweeper/solitaire/ect.), and it didn't mention the fact that FAR more commercial retail games are available on windows, compared to Mac. Chris M. (talk)

It depends entirely on the user. They are nothing more than different operating systems. It is like asking if a motorcycle is better than a van. Both are transportation vehicles, but they meet different needs for the user. If you can state what you plan to do with your computer, there is a possibility that one may meet your needs better than the other. -- kainaw™ 17:59, 27 July 2009 (UTC)

I'm going to be using my computer for gaming (From disks, not on the internet), surfing the web, creating word documents and saving music files in MP3 format (I have an iPod) Chevymontecarlo (talk) 10:32, 30 July 2009 (UTC)

Gaming == Windows. Yes, you can play some games on Macs (and even Linux). Most games work best (or only) on Windows. -- kainaw™ 13:06, 30 July 2009 (UTC)

Game bot/ai

My school will have a programming competition. The idea is to make an algorithm to control pieces of a board game. The game takes place on a MxN grid. It starts by placing K black and white pieces on random positions on the board. On every turn a piece is randomly selected and the algorithm gets to move it. The piece can move one step to one of the 4 major directions, possibly eating an enemy piece, but not off the grid or onto a friend piece. The data the algorithm gets for deciding where to move the piece is what the piece "sees" in the four major directions and the distance to it. If the piece sees a friend piece (instead of the grid edge or an enemy piece), it also sees the "color" of that piece, a 4 byte number (pieces can't see their own color and there's no other memory that lasts longer than a turn). The piece can also set its own color when it gets a turn. A player wins the game if all of his pieces are "connected visually", ie any piece can see all other pieces directly or through other piece that sees other piece ... that sees the piece. (Please forgive my English).

I'm a bit stuck with this. The only thing I can think of is trying to command the pieces towards the center of the board. I don't know any other similar games either. All kinds of help are welcome. --91.145.73.220 (talk) 22:19, 27 July 2009 (UTC)

I'm a bit confused about "The piece can also set its own color when it gets a turn" - does this mean a piece can turn into an enemy piece after it moves?

Also does the algothym get the absolute position of friendly pieces each turn eg (x,y) position

Also a bit confused about "if a piece sees a friend piece" - but then you say "pieces can't see their own colour": Are friend pieces not all either black or white?

Also does player A get the 'views' of player B's pieces, or just their own?

Also what does the "4 byte number" you mention contain? (It sounds like a difficult puzzle by the way - you might want to alert the maths desk to this question)83.100.250.79 (talk) 22:39, 27 July 2009 (UTC)

On the "4 byte number" thing, that means a number (in binary) that has 4 digits (bytes), meaning any number between 0 and 15 (0000 being 0 and 1111 being 15). [flaminglawyer] 22:52, 27 July 2009 (UTC)

... and I don't think the maths desk would help on this one, it's purely programming. [flaminglawyer] 22:54, 27 July 2009 (UTC)

Sorry about the confusion.

1. It cannot turn into an enemy piece. Every turn one (random) piece can move and (must) set its color. Only friend pieces see the color, enemies are seen just as "enemies".
2. The algorithm gets no info but what it sees.
3. Oops, no wonder if this confuses. I meant to say player A's pieces are white and player B's black. Then pieces have a color that is the 4 byte number and only visible to friend pieces. It makes sense if you want to believe into it.
4. I assume you mean the "visual connection" thing, no, enemy pieces cut the connection.
5. The 4 byte number contains the color, the algorithm must set it every times it moves the piece. Initially the color is 0.

--91.145.73.220 (talk) 23:03, 27 July 2009 (UTC)

Good that's clear - actually for 4 I meant : does Player A get a list of what Player B's pieces can see - but I understand now - if a player's piece can't see another piece of the same (black or white) colour as itself it's effectively blind. 83.100.250.79 (talk) 23:31, 27 July 2009 (UTC)

Also 4bytes is 32bits - Can I make the assumption that N+M<=32 ? (ie a smallish board)83.100.250.79 (talk) 23:33, 27 July 2009 (UTC)

That's left somewhat unspecified, but there should be small cases too. Also just to make sure, even if a piece doesn't see a friend in some direction it still knows whether there's an enemy or the grid edge and how far it is from it. --91.145.73.220 (talk) 00:03, 28 July 2009 (UTC)

Huh. Well, one strategy you might think about is that if a piece can see a friendly piece, it probably shouldn't move in a perpendicular direction (so it loses sight of its friend). If it sees a friend to the North, it could move north or south until it sees another friend to the east or west, then stop. If it can't see a friend, it could go any direction, I guess. The "color" sounds like it's just supposed to be used as a state variable, so that when a piece sees a friend, it knows how many friends that friend can see. Or something like that. Anyway, sounds like fun, good luck. Indeterminate (talk) 02:47, 28 July 2009 (UTC)

One useful thing I can think of is that the computer can be programmed to derive the relative positions of connected (viewed pieces), there may be more than one set of view connected pieces (and it may not be immediately certain which pieces can see each other eg if 2 pieces can see a piece 4North, and 2 pieces can see a pieces 4 south there's a 50/50 chance of guessing which piece is actually seeing the other - I imagine the colour seetting function could help here after a couple of moves)

If you construct sets of connected pieces it should be obvious that each set requires a 'sub-board' of at certain size, that can be derived from the data - this sub board size can be used to derive a range of absolute positions for those pieces. A second set of view connected pieces can be used to reduce the number of possibilities for the absolute position of the first set (ie certain combinations are impossible, or connect the two sets)

Using this derived data you can get a expectation (probability) of a given square being viewable or not. Additionally you can get an expectation of where each view-not connected piece might be using the same data set.

Using these two values you can make moves giving the highest expectation of moving towards or into a viewable square. This doesn't guarantee a win, but should increase the chances of winning over many random games..

Apart from using the colour values to help remove uncertainty as to which sets are connected as described above, I haven't really though of a use for them, except to keep track of how much a pieces has moved from it's starting position - which can be useful...

Some of the concepts seem similar to a game of Battleship (game) - maybe there have been some studies of winning strategies for that game which you could find out about?? (and modify)

It's clear to me that the method I've decribed doesn't do 10% of what could be done, though I haven't got a clue what other methods could be used.

In the absence of anything else I'd suggest moving the pieces towards an edge along the shorter length :) 83.100.250.79 (talk) 13:08, 28 July 2009 (UTC)

By the way one issue with the method above is that it's a brute force method, and the number of combinations gets massive rapidly as the board size increases.. It will probably be out of the range of a desktop computer if the board is say 32x32 with 10 pieces each.83.100.250.79 (talk) 13:21, 28 July 2009 (UTC)

Also it might help if number of pieces is always less than 32 - any clues?83.100.250.79 (talk) 13:48, 28 July 2009 (UTC)

There is no "history" any piece can see. Unless...set it up so the number of the colour indicates how many pieces that piece can see. Because you win by having the bigger network of pieces, the piece whose turn it is should move to where it will increase the total "visibles" available to it. So if North-South has a higher count than East-West, it should move NS, in the hope of finding a higher-scoring EW line. If the visible EW is say more than 50% of the possible high score, perhaps it should pass its turn to a brother piece. Giving preference to eating an enemy piece is fraught with danger...if the enemy has his own kind as neighbours, the eating piece might become the victim in the next turn._ KoolerStill (talk) 14:54, 28 July 2009 (UTC)

Colour schemes in GUIs

I thought this would be easy to find, but no! it's not. Could anyone point me in the direction of research papers/articles on good (and perhaps not-so-good) colour schemes in GUIs or similar? There are a couple of names in my head who did research in this area but their actual names escape me now. Thanks in advance. x42bn6 Talk Mess 22:37, 27 July 2009 (UTC)

I don't know of anything specifically (or at all), but I can point you to Google Scholar, which (basically) searches a bunch of papers/articles to find what you want. [flaminglawyer] 22:48, 27 July 2009 (UTC)

This page mentions "Murchs Rules" [3]

Does that ring a bell? There are some other references on the page too.83.100.250.79 (talk) 22:52, 27 July 2009 (UTC)

Thanks, I think that was one of the names. I'll keep looking around. x42bn6 Talk Mess 23:17, 27 July 2009 (UTC)

The importance of consistency in user interfaces has been documented in many human-computer interaction research areas. Don't re-use the same color for different conceptual ideas - it is a source of subtle confusion. Nimur (talk) 23:30, 27 July 2009 (UTC)

July 28

downloading all torrents with wget

So I want to download all of the torrents on The Pirate Bay with wget. I thought this would be a good command:

wget -N -r -l inf --no-remove-listing -A torrent http://thepiratebay.org

also equivalent to

wget -m -A torrent http://thepiratebay.org

It only gives me this:

--18:03:43-- http://thepiratebay.org/index.html => `thepiratebay.org/index.html' Resolving thepiratebay.org... 192.121.86.15 Connecting to thepiratebay.org|192.121.86.15|:80... connected. HTTP request sent, awaiting response... 404 Not Found 18:03:44 ERROR 404: Not Found.

Removing thepiratebay.org/index.html since it should be rejected. unlink: No such file or directory

FINISHED --18:03:44-- Downloaded: 0 bytes in 0 files

Is this because TPB has blocked wget? Why won't it work? :( Mac Davis (talk) 00:43, 28 July 2009 (UTC)

TPB, like many sites written using PHP, uses index.php, not index.html. Indeterminate (talk) 01:14, 28 July 2009 (UTC)

Are you sure this is a good idea? If I'm reading the front page correctly, there are over 2 million torrents on the site. Exxolon (talk) 01:22, 28 July 2009 (UTC)

Yes, after your HDD gets overfilled, catches on fire, and a skull-and-crossbones flashes on your screen, come tell us how it went. ;) [flaminglawyer] 01:34, 28 July 2009 (UTC)

Further... wget will not download the data. It will download the torrent file - a file which you use with a torrent program to download the data. In other words, you will end up with millions of torrent files. By the time you attempt to use them, most will be stale and worthless. -- kainaw™ 01:55, 28 July 2009 (UTC)

He probably wishes to make a competing tracker site and jump-start it by ripping TPB's entire database. APL (talk) 15:37, 28 July 2009 (UTC)

Problems with MSN Audio

I live in Toronto, and used to have video calls with relatives in China with MSN Messenger. Despite the long distance involved, it worked perfectly. However, for apparently no reason whatsoever, the audio stopped getting through two weeks ago; MSN Messenger would take one-second recordings from my relatives' computer and repeat them over and over again. If they say the sentence "It's a lovely day today", I might hear the word "it" repeated several times before hearing the same thing with "today".

Both me and my relatives are able to have video calls with friends in the same city with no problem. Neither of us use Windows XP (which is known to cause choppy audio), and as far as I can tell, there have no changes in the speed of our Internet connection. What might be the problem? --Bowlhover (talk) 03:04, 28 July 2009 (UTC)

Problem with CLASSPATH

Resolved

Hello! I've been working on a Java swing program with NetBeans that uses several ImageIcons that I have created with the NetBeans GUI builder. When I run the program in NetBeans, it works fine, but now I want to distribute it as a .jar file and am having a lot of trouble. I get a java.lang.ExceptionInInitializerError-->NullPointerException that, according to the stacktrace, seems to be caused by not being able to load the files for the ImageIcons. Here's how my project looks:

My NetBeans project/.jar file:
|-->Map (package with all my .class files)
|-->images (package with half of my files for ImageIcons)
|-->photos (package with the other half)

Can I fix this problem by altering the MANIFEST file? What exactly do I put for the argument after the "class-path:"? Is there a better way to do this? I'm going to distribute it to people who have little experience with computing, so I need the execution of the program for them to be as simple as a double-click. I'll appreciate any help or suggestions. Thank you!--el Aprel (^facta-_facienda) 03:35, 28 July 2009 (UTC)

Boy, do I feel stupid! After several hours wasted, I fixed my own problem, and it turns out that I had saved my images as .JPG files, not .jpg files, which doesn't mean anything different to any computer running any OS...but does make a difference for the JVM. Java's case sensitivity applies even to its getResource() method. It hadn't occurred to me that that could have been causing the problem because I thought I had done file I/O and that wasn't case sensitive. Guess the java.io classes call the OS to do the work and get the file, and the OS isn't case sensitive, but Java must handle getting its own resource and uphold case sensitivity. Learn something every day.... I still don't understand why it ran fine in NetBeans even with the wrong case, but at this point, I'm just happy I got the .jar to work.--el Aprel (^facta-_facienda) 22:38, 28 July 2009 (UTC)

It is certainly possible to put the images in the JAR file. JAR files are intended for both .class binary and resource (e.g. images, audio) distribution. Can you printStackTrace() on the error, and post the results? (That might actually hint you in the right direction anyway). Probably the issue stems from some relative path issue; also look at Sun's Java guide for accessing resources in JAR files. Nimur (talk) 22:37, 28 July 2009 (UTC)

Specifically - here's the Retrieving Resources from JAR files guide. Nimur (talk) 22:39, 28 July 2009 (UTC)

Some operating systems do use case-sensitive file names. NetBeans uses the operating system's file handler (because the development SDK is not running entirely inside the JVM), but the deployed program by necessity must use the Java JAR resource manager (because it must do so from the bytecode and be platform portable). Case-sensitive filenames (especially extensions) are a common source of "lost" resources and mysterious "it worked over there five seconds ago!" bugs. Nimur (talk) 16:43, 29 July 2009 (UTC)

call related material required

hi,

i need MO/MT call related information as i am preparing for interview.please help me in this regard. —Preceding unsigned comment added by Sudcool2009 (talk • contribs) 07:15, 28 July 2009 (UTC)

java programming

a program implementing an atm to help security of an institution sign students laptops into and out of the school compound —Preceding unsigned comment added by Qcush (talk • contribs) 12:21, 28 July 2009 (UTC)

When would you like that done by? --Sean 13:36, 28 July 2009 (UTC)

How could an ATM sign laptops out of a compound? What exactly is your question? Do you need help finding such a program, or designing such a program? Nimur (talk) 22:15, 28 July 2009 (UTC)

This program will "sign students laptops into and out of the school compound". I hope this is what you wanted. « Aaron Rotenberg « Talk « 16:03, 29 July 2009 (UTC)

Ask a stupid question, get a stupid answer

package ar.tools;

import java.io.UnsupportedEncodingException;
import java.security.*;

import javax.crypto.*;

import sun.misc.BASE64Encoder;

/**
 * This program will create a digital signature for the literal string
 * "students laptops into and out of the school compound".
 */
public final class DigitalSignature {
	private DigitalSignature() {
	}

	private static final String MESSAGE =
			"students laptops into and out of the school compound";

	public static void main(String[] args) throws NoSuchAlgorithmException,
			UnsupportedEncodingException, NoSuchPaddingException,
			InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
		System.out.println("Message:");
		System.out.println(MESSAGE);
		System.out.println();
		
		BASE64Encoder encoder = new BASE64Encoder();

		KeyPairGenerator asymmetricKeyGenerator =
				KeyPairGenerator.getInstance("RSA");
		asymmetricKeyGenerator.initialize(512);
		KeyPair keyPair = asymmetricKeyGenerator.generateKeyPair();

		System.out.println("Public key:");
		System.out.println(encoder.encode(keyPair.getPublic().getEncoded()));
		System.out.println();

		byte[] rawMessage = MESSAGE.getBytes("utf8");
		MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
		messageDigest.update(rawMessage);
		byte[] messageHash = messageDigest.digest();

		System.out.println("Message hash:");
		System.out.println(encoder.encode(messageHash));
		System.out.println();

		Cipher messageHashCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
		messageHashCipher.init(Cipher.ENCRYPT_MODE, keyPair.getPrivate());
		byte[] messageHashCiphertext = messageHashCipher.doFinal(messageHash);

		System.out.println("Digital signature:");
		System.out.println(encoder.encode(messageHashCiphertext));
		System.out.println();
	}
}

XP SP 2 OR SP 3 (SP2 is not updating)

I have just upgraded my pc but confused with XP SP 2 and 3. Which one I should I choose? Another thing is XP SP 2 (version 2002) is not taking any update (Though update is on) in my new system. But it took lot of updates in my old system. Why this is happening? —Preceding unsigned comment added by 119.30.36.53 (talk) 12:29, 28 July 2009 (UTC)

I think you need SP2 before you can get SP3, as far as I know you should get all, since they include bug fixes.

Start here http://support.microsoft.com/kb/936929 (check the prerequisites section for issues)

Just to save you time - if windows update is not working for you , you can get SP3 via a direct download here http://support.microsoft.com/kb/322389

Question - what's going wrong with 'windows update' is it not starting at all? does it go to the web page, or further than that? Have you checked that it is set to update at a time the computer is on etc? Have you already got SP2 installed.83.100.250.79 (talk) 12:51, 28 July 2009 (UTC)

You should definitely update to Windows XP SP3. There are many bug fixes, security updates, and feature updates involving Windows Firewall, among other things. The reason that on your system, Windows Update completed its cycle and said that your system is up to date even though it didn't download any fixes is that all of the Windows Update updates that have been created by Microsoft for the last couple of years have required SP3. Tempshill (talk) 14:34, 28 July 2009 (UTC)

Actually windows update should automatically install SP3 as well - which makes me think that windows update is going wrong - as it often does to me.

Curiously I just tried windows update and 'hey presto' I find that there is a high priority update to download and instal - which windows update has not told be about either - makes me even more suspicious that something might be (temporarily) wrong with windows update itself

To the OP - if the update gets stuck on the update page, just try again in 5 mins, and try pressing refresh (F5) as well - I would guess that providing updates to x billion computers occasionally causes server issues...

If that's not happening/working please tell how far you can get when trying to update eg when you visit http://windowsupdate.microsoft.com/ what happens?83.100.250.79 (talk) 17:19, 28 July 2009 (UTC)

• I have got XP SP3 DVD. Ok, I want to know whether XP SP3 is better than XP SP2 or not. I mean whether sp3 has better performance in application including game.--119.30.36.40 (talk) 22:07, 28 July 2009 (UTC)

They're separate and individual. One is not 'better' than the other. In order to use 3, you have to have either 1a or 2 already installed. There's no reason not to have all three; 3 is not an improved version of 2, they are completely different programs. HalfShadow 22:11, 28 July 2009 (UTC)

Answers: [4][5] also look at http://www.google.co.uk/search?q=does+sp3+improve+performance&hl=en&start=10&sa=N for more results.83.100.250.79 (talk) 13:38, 29 July 2009 (UTC)

• Excellent answer ! This is what I was looking for. Thank you so very much annon :)--119.30.36.42 (talk) 18:20, 29 July 2009 (UTC)

Fujitsu laptop...possibly dead

My laptop has had a tendency of late of only working when plugged in to the mains, which is fine. Except last night when I loaded up as normal only to be greeted with my desktop full of "interference" and broken imagery. In a state of mild panic I unplugged the battery from the latop, following which the laptop duly died.

From last night onwards, I can turn the machine on - the on light is functioning and the DVD drive "clicks" to suggest it is being checked as per a normal process. From this point the thing doesn't go any further - no screen activity, no futher boot-up activity, no encouraging whirring noises, nothing.

Has my laptop passed on to the great customer advice centre in the sky, or is there something (anything?) I can do to solve what's gone wrong?

Many thanks in advance.....80.193.130.5 (talk) 13:41, 28 July 2009 (UTC)

It's most likely the motherboard or video card that's died. If you know how, or if you take it to a computer shop, you can probably get the data recovered from the hard drive. But if it's more than a year or two old, fixing the laptop itself might cost more than a new one. Indeterminate (talk) 01:53, 30 July 2009 (UTC)

Programming mouse buttons

How can I program my extra mouse buttons so taht pressing them will be the same as pressing a couple of keyboard buttons one after the other? So instead of pressing say, 2-b-b-1, I can just press the extra mouse button and it will be as if I pressed those buttons in that order? —Preceding unsigned comment added by 92.251.255.11 (talk) 15:42, 28 July 2009 (UTC)

Some mice with programmable buttons come with software to do that and manage other settings. See if your mouse came with a CD containing this software, or check the vendor's website for a download. Xenon54 (talk) 22:34, 28 July 2009 (UTC)

You didn't mention an OS, but for Windows AutoHotkey is a useful free program that can reprogram your mouse buttons do practically anything. -- BenRG (talk) 17:00, 29 July 2009 (UTC)

Plucker and Ebook readers

After the sad demise of Avantgo, I use Plucker and Sunrise to move online news articles and other content onto my Palm Tungsten E2. It takes a little effort, but generally works out. Can anyone tell me whether or not, and how (easily) Plucker-Sunrise content can be rendered and uploaded to a Sony PRS 505, or 700. My favorite app on the Ereader, I think, would be nytimes.com, economist.com, nameyourepublication.com...but I can't quite make out how those kinds of docs get onto that device. Thanks if you can advise. —Preceding unsigned comment added by 83.98.238.113 (talk) 18:11, 28 July 2009 (UTC)

Proxy

I was just wondering if there is any website from where i can get free live proxies... or is there anyother way to change the ip address ... as there are some sites where i cant enter because of my location , so i was like if i get some proxies of other locations and i use them for my explorer ?? And could you guys please guide me too , how to use proxy IN a proper right way ? Thanks in advance —Preceding unsigned comment added by 202.147.172.236 (talk) 21:44, 28 July 2009 (UTC)

How about Tor? It seems like that would simplify things a bit. --98.217.14.211 (talk) 22:10, 28 July 2009 (UTC)

Surely the original poster is not seeking to circumvent an impending IP block for his numerous vandalism efforts? Several warnings on the talk page seem to have had no effect. If you continue to vandalize Wikipedia as you did this morning, and on other earlier occasions, you can be blocked; and we're pretty good at figuring out you've come back with a new IP. Nimur (talk) 22:19, 28 July 2009 (UTC)

Tor is the standard for this, and, as Nimur is probably right, I'll note that Wikipedia doesn't allow editing from Tor proxies, or any other open proxies ... so I wouldn't waste your time, OP. Tempshill (talk) 23:53, 28 July 2009 (UTC)

I didnt get u guys.. what is Tor ?? is it also some form of proxy or what ? —Preceding unsigned comment added by 202.147.172.236 (talk) 15:13, 30 July 2009 (UTC)

If you read Tor like the first reply suggested, you will see all. Technicalities aside, it works like a proxy. You install the Vidalia software, and you can get a plugin for firefox to help you use it. 86.17.139.211 (talk) 22:51, 30 July 2009 (UTC)

I'm sorry, 98 was right. I mean Tor (anonymity network), not Tor, which is obviously the wrong article.86.17.139.211 (talk) 11:07, 31 July 2009 (UTC)

When a computer was first activated

Is there any way to tell from your PC's files alone what date your computer was first activated? I checked the dates for the HDD and keyboard drivers, and both said 6/21/2006, which seems mostly accurate to me. However, I did this on another computer (bought about 8 months ago) and got the same results.--The Ninth Bright Shiner 22:36, 28 July 2009 (UTC)

That's unfortunately when the file system claims the file was created or modified. It does not mean that the computer that the file now resides on was active at that time. File-systems have varying conventions about reporting create-, modified-, and last-accessed- times. Many of the system files on my Windows XP machine all show create-times from before my computer ever existed (because when those files were copied from the install CD, they carried over the create- and access- times from the Microsoft developer's environment where they were actually compiled). Even if the file shows an access time for the true, correct date and time it was put on to the hard-drive, that only tells you when the hard disk drive was active - it tells you nothing about the motherboard, CPU, RAM, etc. Your harddrive could have been programmed by an OEM in a separate machine designed for pre-loading disk images, and then placed into your current system. Nimur (talk) 22:44, 28 July 2009 (UTC)

There may be a install date buried somewhere deep in the registry. I know, for instance, that there's a reboot counter, which might provide some interesting background. But I would suggest looking at user creation dates, most of all for the administrator user, but also for any non-admin users (most people won't delete the original account), and use that in connection with other created dates on the computer to get a pretty good idea of the first install. Also, you might be able to dump the NTFS headers and see when the filesystem was created. I don't remember for sure, but I think NTFS stores this information somewhere. There are other quirky ways you could probably figure this out, but try those few things and let me know if it works. Shadowjams (talk) 07:12, 29 July 2009 (UTC)

If you want to know when the operating system was installed, I think you can look at the creation time of certain folders. For example, on my Windows XP computer, the Windows, Documents and Settings, and Program Files folders in the C: drive all have very similar creation times which seem to correspond to when the OS was installed. --Bavi H (talk) 00:34, 30 July 2009 (UTC)

If you run systeminfo, one of the things it'll tell you is "Original Install Date". Handy little tool. Comes with everything since XP by default. Indeterminate (talk) 01:45, 30 July 2009 (UTC)

I'm not so good at command prompt, so I could use just a teensy bit more help. >_< I did run systeminfo, but the only relevant date I could pull was 8/20/2007, which does happen to be when I installed Vista. A clean install, by the way. Would a clean install prevent me from learning the true date?--The Ninth Bright Shiner 19:39, 30 July 2009 (UTC)

Ah, yes, you did it right, but if you did a clean install, then all the previous dates and things on your hard drive would have been erased. There's not generally any way to find out when previously installed versions of Windows were activated. :) If you bought it from an OEM like Dell or something, you could probably call tech support and ask them. They could probably at least tell you when it was put together. Indeterminate (talk) 01:45, 31 July 2009 (UTC)

I thought as much. :-( Well, 21 June 2006 sounds accurate enough, but I guess I'll never quite know the truth. Systeminfo does seem interesting though, so thanks anyway!--The Ninth Bright Shiner 23:43, 31 July 2009 (UTC)

Resolved...kind of.

July 29

Game

What is the largest computer game ever made in terms of file size? Jc iindyysgvxc (talk) 00:47, 29 July 2009 (UTC)

Perhaps some game/movie hybrid? One were they would have to record more than the normal movie lenght? --_{Piotr Konieczny aka Prokonsul Piotrus| talk} 01:07, 29 July 2009 (UTC)

I am going to guess that it is World of Warcraft. Most of the file data is of course on the WoW servers. I'm sure they store a gigaton of data that tracks player activity. Tempshill (talk) 01:39, 29 July 2009 (UTC)

I remember back in the good old days (ha) of CD-ROM gaming when games that used multiple CD-ROMs ran ads telling you how many floppies it would have taken to play the game as it was (Under a Killing Moon advertised itself as being the equivalent of HUNDREDS of floppy disks!). Ah, well. But yeah, as noted, are you asking about total size installed on a hard drive, or kept on local disks, or distributed on a network? Probably different answers in all cases. --98.217.14.211 (talk) 15:10, 29 July 2009 (UTC)

Metal Gear Solid 4: Guns of the Patriots says "Guns of the Patriots is the first PS3 game that uses a full 50GB dual layer Blu-ray Disc, even after extensive efforts in data compression." This might be the current record for local data, since publishers are presumably loath to require two discs. -- BenRG (talk) 17:13, 29 July 2009 (UTC)

How many wikis are out threre?

Are there any reliable estimates on how many different wikis are out there? Wikia claims to host at least 1,500. --_{Piotr Konieczny aka Prokonsul Piotrus| talk} 01:06, 29 July 2009 (UTC)

It will be hard to reliably count. An overwhelming percentage of wikis are for "internal use only" in organizations, and are either not publicly visible or not publicly editable. If you intend to count non-public wikis, it will be very hard to come up with reasonable estimates. Nimur (talk) 01:32, 29 July 2009 (UTC)

Since the software is completely free in many cases, this question is like asking "how many non-wiki websites are there out there", but it's certainly lower than that. Chris M. (talk) 12:16, 29 July 2009 (UTC)

SQL Noob needs help

Hi All,

Is there an easy way to do this using sql: generate a table with two columns, one a field from the database and the other the number of times it occurs? Something kinda like: SELECT COUNT(CustID) AS totalOrdersFromCust FROM Orders_table WHERE CustID='id-here' except it will go and loop through the database so I end up with the number of times each customer has placed an order?

ex:

custID    totalOrders
1         24
2         16

etc..

I know there's gotta be a better way the me having to write a loop with an external app.

Thanks in advance! PrinzPH (talk) 02:16, 29 July 2009 (UTC)

select CustID, count(*) as 'NumberOfOrders' from Orders_table group by CustID --Nricardo (talk) 02:50, 29 July 2009 (UTC)

Resolved

Thanks Nricardo, Works! PrinzPH (talk) 22:31, 29 July 2009 (UTC)

Windows XP Hibernate Mode

Hello. How can I stop my computer from turning on immediately after hibernating it? There is more than enough space for hibernation. I read an identical question but it was unhelpful.

My computer spontaneously turns on only at 8 PM (EST) everyday. Regardless of when I hibernate my computer, the hibernation finishes but the computer turns on.

I was able to hibernate my computer even when I had an Ethernet card. Thanks in advance. --Mayfare (talk) 03:54, 29 July 2009 (UTC)

Reboot the computer and hit DEL (or whatever) to enter the BIOS screens, and scour the screens looking for the option to power on every day at a certain time, and, as was mentioned in the earlier thread, the option to power on when Ethernet packets are received. And any other options involving powering on; and turn them all off. Tempshill (talk) 04:05, 29 July 2009 (UTC)

Also go to Scheduled Tasks in the Control Panel and see if there are any tasks scheduled for 8 PM with "Wake the computer to run this task" checked in the properties (Settings tab). -- BenRG (talk) 08:18, 29 July 2009 (UTC)

How do I make my Ethernet card not turn on my computer when it receives packets? --Mayfare (talk) 16:40, 30 July 2009 (UTC)

Shell script issue

Resolved

When I run the following shell script, I expect domain names which return data to wget to be listed on the terminal where I run the script, and those which don't to be listed on /dev/pts/4. Instead, all domain names are listed on /dev/pts/4. I've tried commenting out the for loop and instead setting $line to just one domain; if I do this, it works fine. What am I doing wrong with the loop?

On a related note, when iterating wget over 2070 domains that may all be hosted on the same server, are any precautions necessary to avoid triggering the server's DoS defenses? NeonMerlin 07:05, 29 July 2009 (UTC)

#!/bin/bash
IFS="
"
for line in $(cat complete-scientology-domain-list.txt);do
  if wget -O - $line 2>/dev/null | grep ".*" >/dev/null; then
    echo $line
  else
    echo $line > /dev/pts/4
  fi
done

Setting IFS to newline means that any spaces in the input file will be treated as part of the URL. Don't set IFS and it should work. You should also put double quotes around all $line references. --Sean 14:41, 29 July 2009 (UTC)

To avoid triggering any defense mechanisms, check for a robots exclusion standard (GET /robots.txt). If the server is well-configured, the robots.txt file will specify rules for what you are doing (typically this means pausing between requests, e.g. pulling no more than one page per second, for example). Note that the robot exclusion "standard" is not really a "standard" - it is more of a guideline for "playing nice" with the host. A web server may choose to enact blocks or other defenses without specifying a reason. Nimur (talk) 15:40, 29 July 2009 (UTC)

Tried dropping IFS and quoting $line. Still doesn't work. NeonMerlin 16:21, 29 July 2009 (UTC)

Update: Does work correctly with the last domain name in the file (which doesn't end with a newline). Maybe it's an issue with how cat processes the line breaks. NeonMerlin 16:42, 29 July 2009 (UTC)

The file might have Windows/DOS line endings. Do a "dos2unix complete-scientology-domain-list.txt" and then try again. --Sean 14:01, 30 July 2009 (UTC)

Did the equivalent in kate, set sane timeout and tries for wget, and now works. NeonMerlin 14:25, 30 July 2009 (UTC)

Bluetooth mice

Are bluetooth mice any good? I'm getting a laptop and wireless mice with a small receiver and bluetooth mice seem to be in the same price range, but I've heard quite a bit of bad press towards bluetooth mice. Are they really worse than normal wireless mice? Do they interfere with WLAN much? Thanks. --antilived^{T | C | G} 07:11, 29 July 2009 (UTC)

Not sure if what I'm saying is accredited but my Logitec one works great, just like a regular mouse, and works on pretty much any surface but ones with reflective coating. I'm glad I have one; the touchpads are pieces of crap in my opinion. -- penubag  (talk) 07:29, 29 July 2009 (UTC)

Thanks for the info. Mind telling me the model? --antilived^{T | C | G} 10:45, 31 July 2009 (UTC)

Bluetooth shouldn't (and hasn't, ever, in my experience with them) interfere with WLAN, or any other wavelength. Bluetooth has its own frequency, which coexists with the rest of 'em. [flaminglawyer] 13:18, 29 July 2009 (UTC)

Both Bluetooth and 'WiFi' use the 2.4GHz band. (excluding WLAN that uses 5GHz) There is the potential for a bluetooth signal causing the WiFi to operate at a lower rate. Other devices also use this bandwidth (eg xbox 360 controllers, some wireless telephones etc), additionally your neighbours WiFi may also be wanting some of that bandwidth too.

For a discussion (very technical) see the first three links of http://www.google.co.uk/search?hl=en&q=bluetooth+wifi+interference&meta=&aq=f&oq= to complicate things it seems that different devices may be better or worse than others - in terms of avoiding bandwidth conflict, as well as the relative power of there signals - it's complicated (business have to employ specialist engineers see if a big system can work) but a 25% reduction in WiFi WLAN bandwidth is possible even expected, and it can be worse.

In general though they work fine (in my experience) in a home enviroment.

You can get wireless mice that operate at other frequencies (eg 750MHz I think) - most suppliers will have this info about there mice, if you look at the tech specs.

If you are using WiFi WLAN as networking between computers and you require it to be as fast as it can possibly be then bluetooth is something to factor out. Under most conditions (internet browsing, small file transfers between computers) it shouldn't be an issue.

A lot depends on were you live - a new york office is going to be much more demanding (due to the number of devices all around) than a house in the middle of a park.83.100.250.79 (talk) 19:49, 29 July 2009 (UTC)

The primary reason why I'm concerned about interference is because my desktop mouse interferes with my WLAN and freezes for a few seconds once in a while. If all bluetooth is gonna do is slow down WLAN I'm fine with it, since it's not like I'm transferring files over it anyway. --antilived^{T | C | G} 10:45, 31 July 2009 (UTC)

Updating system software on a PSP 2003

Does anyone know how to update system software on a PSP 2003?Chevymontecarlo (talk) 08:07, 29 July 2009 (UTC)

See Sony's PSP update page for instructions, at the bottom of the page, on updating your PSP, by using a PC, a UMD disc, or, the easiest way, logging in to a WiFi network anywhere and choosing "Network Update". Tempshill (talk) 15:50, 29 July 2009 (UTC)

It worked - thanks. Chevymontecarlo (talk) 10:34, 30 July 2009 (UTC)

imaginary vbScript

Can vbScript handle complex numbers? If so, how does the syntax work? Thanks —Akrabbim^talk 14:38, 29 July 2009 (UTC)

According to [6] no.

There are modules that will add support via functions eg [7] , there are more extensive librarys which could be adapted using the same methods. eg [8]

A here's a list of some languages that do [9] if you need it.83.100.250.79 (talk) 14:51, 29 July 2009 (UTC)

trackboard

complete information about trackboard in computer —Preceding unsigned comment added by 116.68.94.36 (talk) 14:58, 29 July 2009 (UTC)

The only computer-related "trackboard" I've found is this product. If you have a specific question, please ask again and remember that you're dealing with people, not a search engine. --LarryMac | Talk 15:02, 29 July 2009 (UTC)

Google finds a company by that name that makes keyboards with embedded trackballs. But maybe you meant circuit board? -- Finlay McWalter Talk 15:03, 29 July 2009 (UTC)

or perhaps Stripboard ? -- Finlay McWalter Talk 15:14, 29 July 2009 (UTC)

Or maybe the mysterious semi-vaporware, Phantom Lapboard? Nimur (talk) 15:44, 29 July 2009 (UTC)

Did you mean Touchpad aka 'Trackpad' ? 83.100.250.79 (talk) 19:33, 29 July 2009 (UTC)

linux backup/restore

A couple of kinda related linux questions
1)when i installed linux (fedora 10) i installed /boot, /, and /home as separate partitions. Now the other day i had a slight hd drive problem, and decided i needed to reinstall /boot, how can i do this without having to reinstall /, as when i used a live cd installer it told it needed to install /
2) after reinstalling fedora i used rsync under root to copy back all the files, as i had backed up / on a removable hard drive, but it doesnt seem to of copyed back programs, the files seem to be there in the backup folder but it doesn't seem to of copyed back to my pc, anyway to fix this?
3) i currently use rsync under cron doing this command "01 18 * * * root rsync --archive --compress --backup --delete --exclude-from=/home/rob/exclude / /path/to/backup/directory' and exculde the following /media/ /proc/ /sys/ /tmp/ /mnt/ /usr/share/man/
a)is there any other files/folders that can be excluded
b)would running rsysnc with any different/extra options be more beneficent?
thanks--90.207.181.210 (talk) 16:49, 29 July 2009 (UTC)

looks like 2 was due me writing a bad path on the rsync to copy the stuff back--90.207.181.210 (talk) 10:56, 1 August 2009 (UTC)

MATLAB string analysis

I have a string:

>> line = # GHZ S RI R 50.000000;

I want to grab each element as an individual string, and then convert the last into a number. After looking around, I tried this and got an error:

>> header = regexp(huh,' ','split')
header = 
   '#'    'GHZ'    'S'    'RI'    'R'    '50.000000'
>> str2num(header(6))
??? Error using ==> str2num at 33
Requires string or character array input.

For all I can tell, header looks like a matrix of strings so I don't know why str2num isn't accepting it. Maybe it's just because I don't understand all this regular expression nonsense, but what am I doing wrong? Is there a better way to split this string? Thanks, —Akrabbim^talk 19:04, 29 July 2009 (UTC)

Does MATLAB indexing start at 0? If so, you'd want header(5). --19:37, 29 July 2009 (UTC)

No, it doesn't. It starts at one, so:

>> header(6)
ans = 
   '50.000000'

—Akrabbim^talk 19:40, 29 July 2009 (UTC)

While you're waiting for the answer - I can suggest a few things to try to see if you can find out whats going wrong - try the "ischar" and "isnumeric" functions on header(6), try the expression str2num("50.000000") to make sure the decimal isn't confusing it, also try passing header(6) to a single non arrayed variable eg 'tempv' and then using "str2num(tempv)" - to make sure the array isn't confusing the type checking on the function. I can;t actually see anything wrong myself.83.100.250.79 (talk) 20:28, 29 July 2009 (UTC)

I'm just guessing (again), but since nobody else has jumped in yet ... I've been perusing the online documentation and can't find anything obvious, but can you try header{6} ? i.e. curly braces instead of parentheses. I think header might be a "cell array" and you need to access the contents of a cell rather than the cell itself. --LarryMac | Talk 20:33, 29 July 2009 (UTC)

That does seem to be it - described here [10]. Curly brackets should fix it.83.100.250.79 (talk) 21:35, 29 July 2009 (UTC)

Actually I'm getting a bit confused because 'regexp' according to [11] has a different syntax, and doesn't do what you want - it checks for matches oh "huh" must be the strings name.- you want to tokenise.??

You could try "strtok" as well , see [12] —Preceding unsigned comment added by 83.100.250.79 (talk) 20:44, 29 July 2009 (UTC)

Larry, you are right. Is is a cell, so header{6} is what I need. I didn't know that cells were any different, so thanks for the educational link 83. —Akrabbim^talk 15:54, 30 July 2009 (UTC)

Resolved

Time Machine on a Mac

Hi. I have recently purchased a 500GB Time Capsule to back up my iMac and MacBook Pro. I first set up Time Capsule on my iMac and all was hunky dory. However, when I tried to set it up on my MacBook Pro, it came up with 'Time Machine Error. The backup disk image could not be created.'. I haven't the faintest idea what this means or, more importantly, how to rectify it. Could someone help me out please? Thanks. 92.0.232.90 (talk) 19:42, 29 July 2009 (UTC)

That error means that the Time Machine program could not create the database for saving old versions of your file. According to this Apple discussion forum, you need to set your computer's "Network Name" (in the System Preferences utility, this can be set in the "Sharing" tool, under "Computer Name"). Time Machine probably requires a computer name to be properly set so that it can create a unique database just for that computer. Nimur (talk) 20:01, 29 July 2009 (UTC)

This is no doubt going to jinx it but setting a Network Name (which I did not have before) got everything going just like with my iMac. Thanks Nimur! 92.0.232.90 (talk) 20:22, 29 July 2009 (UTC)

Apples ownership of adobe systems

Can you tell me what the high watermark percentage of Apples ownership of adobe was? I know that at one time they owned more than 16% but I think the high watermark was closer to 25%. Brafferty (talk) 20:31, 29 July 2009 (UTC)

Switching from GPL to closed source

The AutoHotkey article states that the authors released their code under the GPL, became frustrated, and then declared their future work with the code base was to be closed source. In the cited source (it's a chat board thread), the apparent author of the software states, "As we wrote all the code we can depart from the GPL if we choose. Previously downloaded source would still be under GPL (as per the license) but new copies of the source would be under whatever license we care to make."

Is this correct? I know there's very little case law in any country regarding the GPL, but I guess I had thought that once the author releases code under the GPL, he is a licensee as well, and as a user of the code, would have to abide by the GPL's terms, including releasing free, GPL'ed source code of any derivative works. If the author's statement is correct (and it does sound logical to me that he doesn't have to be a licensee) then that's an interesting wrinkle. Tempshill (talk) 20:46, 29 July 2009 (UTC)

My understanding is that only the copyright holders may sue if there is a breach of the GPL. If all copyright holders decide that they do not want the GPL and will not sue about ending the GPL license, then the license may be changed without any legal problems. It is the perception of the people that once something is GPL it is absolutely free and owned by the world. That is a completely false perception. Having such a perception leads to the perception that the copyright holders are stealing from the world by taking their code closed source. -- kainaw™ 20:56, 29 July 2009 (UTC)

The question is really about whether a developer who has moved to closed source can sue YOU for using it under the old open source agreement, not whether the developers will sue each other over it. --98.217.14.211 (talk) 21:15, 29 July 2009 (UTC)

(edit conflict):I can't see any stand up argument that would prevent someone/group changing the licencing arrangements for their own work (assuming no other contributers disagree) applying to future products (retroactive license changes are non-runners/difficult/debateable though) - the license isn't a contract that requires the producer (ie the one with the intellectual property rights) to continue to license all their work in perpetuity.

As you say the manufacturer is not a licensee.I'm not a lawyer83.100.250.79 (talk) 20:57, 29 July 2009 (UTC)

Copyright holders can release their code under multiple, non-exclusive licenses at different times. They are not obligated to release their new code under GPL just because the old code was, if they were the original copyright holder (the one who is issuing the licenses in the first place, not a derivative user). However, they cannot "withdraw" the GPL license on the original code. See [13] and [14]. --98.217.14.211 (talk) 21:15, 29 July 2009 (UTC)

The Mocha (decompiler) was "licenced" (if one can count a single line in a readme.txt as a licence) thus: "The distribution archive (file "mocha-b1.zip") may be distributed freely, provided its contents are not tampered with in any way." - it's no GPL or open source (only .class files were distributed) but it was a distribution-permissive licence. According to this page the author died, and Borland acquired the rights to Mocha. The author of that site quotes an email he says he received from Borland telling him that, despite the readme, he couldn't distribute it any more. He says he told them to shove off and he's still distributing the software. The situation should be clearer for GPL software being retroactively pulled (as opposed to simply relicenced-from-now-on), as the GPL is a properly written licence rather than a passing one-liner. Note, incidentally, that to contribute to some GPL software (that is, to get your patches into the core tree) you need to assign copyright (not just GPL licence); I think that's always been the case for MySQL - the current Sun scheme is a bit more liberal, but you still need to jointly assign copyright (ref) - which would allow Sun (or Oracle, soon) to take future revisions of the software closed source. -- Finlay McWalter Talk 21:44, 29 July 2009 (UTC)

The process is actually pretty simple. If (say) version 1.0 of a particular piece of software is released under the GPL, then the copyright owner (and nobody else) can choose to change the license on (say) version 1.1 to be a closed-source license. However, the source code to version 1.0 can still be redistributed under the terms of the GPL - it can be improved upon, added to - even made compatible with version 1.1 - and it'll STILL be under the GPL. However, the copyright holder's version 1.1 is now closed source - and you're not allowed to redistribute it. Only the copyright holder can do make that decision...and for most OpenSourced software were there are several (if not dozens or even hundreds) of authors, it takes the agreement of every single one of them to change the license terms (unless it's possible to identify the changes that a particular person made and back them out such that none of his copyrighted additions remain in the package). So most large/common packages are safe and cannot ever be closed off. But even when the original author does own the entire copyright - the community has lost nothing. The version that was out there on the day before the license changed is still out there under GPL - and you can try to put a team together to maintain and improve it. Since the community-maintained and the (now) commercially maintained packages are competing with each other on an (initially) level playing field, there is no reason to assume that the package will not continue to thrive as an OpenSourced package. SteveBaker (talk) 23:55, 29 July 2009 (UTC)

Thanks everyone for the answers. Tempshill (talk) 00:17, 30 July 2009 (UTC)

Video Conversion

Is there any free software that i can use to convert dvr-ms (the format used by recorded tv from Windows Media Center) to a common format such as mpeg or avi. I have tried avidemux but the audio is really out a sync and i generally cant get it to convert correctly. Any ideas on good video conversion software or how to use avidemux properly would be greatly appreciated. —Preceding unsigned comment added by 86.177.127.22 (talk) 21:07, 29 July 2009 (UTC)

Some options for editing, transcoding, and simple rewrapping are discussed in the DVR-MS article. -- Finlay McWalter Talk 22:07, 29 July 2009 (UTC)

MEncoder and ffmpeg support conversion of dvr-ms files. There's a good GUI for ffmpeg available here // 21:48, 30 July 2009 (UTC) —Preceding unsigned comment added by 4k01 (talk • contribs)

Downloading flash-based video

I'm looking for a program or browser-plugin that enables downloading of flash based video from a web site, specifically this site, in a format playable by media players such as Windows media player, VLC media player or Quicktime. OS: Windows XP, or Linux (Debian or Ubuntu). Anyone aware of such a beast? --NorwegianBlue ^talk 21:16, 29 July 2009 (UTC)

I was able to download the FLV file using FlashGot in Firefox. VLC can play FLVs and there are no doubt codecs that let you play it in everything else as well. --98.217.14.211 (talk) 21:24, 29 July 2009 (UTC)

Thanks a million! Worked like a charm. --NorwegianBlue ^talk 21:55, 29 July 2009 (UTC)

Resolved

Addendum: I'd like to add, in case anyone else is interested, that the file was easily transcoded to a format recognizable by Windows Media Player, using the transcoding wizard of VLC media player. --NorwegianBlue ^talk 22:12, 29 July 2009 (UTC)

Also the VLC Player can output video as ASCII art, realtime.. probably worth a download just for that.. 83.100.250.79 (talk) 15:15, 30 July 2009 (UTC)

USB flash drive size conventions

Hello wikipedia!

Why do USB flash drives come mainly in sizes related to binary numbers? 256Mb, 1Gb, 8Gb, etc? Hard drives and CDs just have a number, presumably the biggest number they could get with the current technology.

A google search for 5gb flash drive returns a fraction of the hits for 8bg flash drive.

Thanks Fenton Bailey (talk) 21:53, 29 July 2009 (UTC)

The drives are that size because the flash memory chips they contain are sized in powers of two. Those chips (like almost all memory chips, like the DRAM chips in your computer for example) use a memory addressing scheme to refer to the individual chunks of memory they contain. Those memory addresses are passed around on so many wires, each of which carries just a 1 or a 0; (simplifying a tad) that's an address bus. If I have n wires in my address bus, I can address up to 2^n chunks of memory. You could, if you really wanted, have n lines of addressing but a bit less than 2^n bytes of memory, but really there's no point in doing that (and it makes code that deals with the device as a whole more complicated, as it has to remember that not all valid address values correspond with memory). Additionally, frankly that's how electrical engineers have been doing things for so long that their brains, and the tools they use to do things, work much better in powers of 2. Now you might ask why this isn't true for hard drives too - again, hard drives expose the underlying technology, but as the geometry of hard disks is a lot more complex this doesn't make for nice powers of two, but a bunch of weird numbers. Lastly, back on flash-usb disks, you could ask "why couldn't they put in a 4Gb chip and a 1Gb chip and release a 5Gb drive" - they could (there's really only room in a usb flash drive for one or two chips) but the cost increment for them in going from a 1GB to a 4Gb chip is so little that they might as well put in 2x4G at little extra cost, and they can charge you (quite rightly) a good bit more. -- Finlay McWalter Talk 22:05, 29 July 2009 (UTC)

Given the fact that pretty much every decent flash drive has circuits for wear levelling, the extra complexity for remembering which addresses are valid and which ones aren't is probably trivial. -- 128.104.112.87 (talk) 00:52, 30 July 2009 (UTC)

Is that really true? The flash drives I've used all had capacities in decimal MB and GB (the 256MB ones hold about 256,000,000 bytes, the 2GB ones hold about 2,000,000,000 bytes). A 1GB drive is not twice the size of a 512MB drive, it's only about 95% larger. I know they have some extra sectors for defect management or wear leveling or whatever, but I don't see why the ideal fraction of extra sectors would be 1.024ⁿ where n is 2 or 3 depending on the unit used to describe the drive size. -- BenRG (talk) 18:15, 31 July 2009 (UTC)

The acid test is to crack the thing open and we'll look up the flash memory part's datasheet. -- Finlay McWalter • Talk 18:33, 31 July 2009 (UTC)

July 30

Compressed HTTP

In compressed HTTP, can transmission begin while compression is still in progress, and can decompression begin while downloading is still in progress? If so, what software actually does this? NeonMerlin 00:31, 30 July 2009 (UTC)

HTTP compression - yes and yes, sort of. It's not actually separate software, exactly, that does the compression/decompression. It's usually just a built-in feature, although it might be a specific library or plugin that the browser/server uses. Instead of compressing the files, then sending the compressed file, it usually gets streamed to the compression module which compresses it, then sent over the internet, received by the browser, which streams the compressed data to the decompressing module as it receives it, which then streams the uncompressed data to the rest of the browser. AFAIK. The links in the http compression article might help more. Indeterminate (talk) 01:35, 30 July 2009 (UTC)

difference between core 2 duo and dual core

Could anyone explain to me in what way core 2 duo processor is different from a dual core processor ? srini 05:02, 30 July 2009 (UTC) —Preceding unsigned comment added by Srini279 (talk • contribs)

Bear with me - there is some confusing terminology here. Intel has released CPUs under the brand names "Core 2 Duo" and "Dual-Core". "Dual core" can also be a generic technical description, which has nothing to do with the brand-name.

The term "dual core" can mean any system that has two CPU cores. A CPU "core" is the basic instruction processing pipe - so two cores means that the CPU can simultaneously process two instructions in the same clock cycle (rather, it has an entirely duplicated instruction pipeline, including fetch, decode, and execution logic). "Intel Core" is also a brand-name for a certain microarchitecture, designed by Intel. "Dual Core" refers to the brand name of certain Intel CPUs that use that architecture. The Core 2 Duo is a higher performance CPU than the Pentium Dual Core, because it uses a newer microarchitecture, the "Intel Core Architecture, version 2" - "Core 2". Core 2 Duo means that the CPU has two Core-2 cores. In my opinion, the marketing teams intentionally made the names confusing to obfuscate easy decision-making on the part of the consumer (but I'm a bit of a cynic). Pay close attention to whether "Core" is capitalized or not; and Dual-Core vs. dual core - this should help differentiate between descriptive vs. "brand-name" usage.

Take a look at Pentium Dual-Core and Core 2 Duo for technical overviews of the Intel CPU series/brands. Also see dual core (for the generic term) and how it is understood by computer architects. The technical details of the different Intel CPU series are a bit dense for a beginner; your best bet is to read these articles and also take a look at the different processors in each series. But briefly, all Core 2 CPUs are 64 bit CPUs built with newer technology; the Pentium Dual-Core is sort of a souped up Pentium D (which is a souped up Pentium 4). The lowest-end processors in both series actually do not have two cores. Nimur (talk) 05:30, 30 July 2009 (UTC)

Here's a nice breakdown of different Intel processors, including the Core, Core 2, and Dual-Core.

Lenovo Laptop

I will be purchasing a laptop within the next two weeks and wondered if anyone had any experience with Lenovo. I had not heard of this company prior to reading an ad in the paper, and I did know if they were a good manufacturer of laptops. If anyone has any strong preferences for laptops, please let me know that as well. Thanks. --Think Fast (talk) 05:55, 30 July 2009 (UTC)

Lenovo is the Chinese company which bought the PC division from IBM. They now own the rights to manufacture ThinkPads, and in my opinion, they continue to produce fine quality, sturdy computers. Every mobile computer I have ever purchased (in fact, every mobile computer I have ever used for business, too) has been either an IBM or Lenovo system; I currently use an Lenovo IdeaPad S10e mobile computer for portable computing. In the next few days, a story about my unconventional uses for my ThinkPads may be appearing on the Lenovo website; I'll keep you posted if they decide to publish it... Nimur (talk) 06:07, 30 July 2009 (UTC)

What is that? can you tell us, the cylinder bottom right looks vaguely like a thermolysis chamber but the metal plates on the end are about 2" thick. Is it safe/legal?83.100.250.79 (talk) 09:15, 30 July 2009 (UTC)

Vista and USB flash drive

I'm new to Windows Vista and I just plugged my USB flash drive into my laptop whereupon Windows asked whether I wanted to scan the disk for errors that may have been caused by not waiting for file writes to complete. I elected to perform the scan but after a long period of scanning (about 30 minutes or so), no progress had been made at all, according to the progress meter. I note that when starting certain systems up with the flash drive already plugged in, Windows also asks to scan it and then seemingly makes no progress. Is it sensible to scan flash drives for errors in this way and if so, should it take such a long time? ----Seans Potato Business 06:48, 30 July 2009 (UTC)

As I understand it (most) flash controllers automatically isolate any bad(broken) sectors and remove them from the usuable memory - so there should be no need to scan for errors, also since it does work I would suggest not to use it.

However I seem to remember reading that vista has specific support for flash drives - so it should know what it's doing - which in a bit contradictory - I'll see if I can find out more, or maybe someone else will have the answer.83.100.250.79 (talk) 09:43, 30 July 2009 (UTC)

I usually go ahead and run the scan, but if it looks like it's going to take a long time I just cancel it. If you eject/unmount the drive properly before pulling it out, this sort of thing shouldn't come up in the future. If the last files you copied over or edited on the flash drive weren't that important, you can probably skip the disk scan. But keep in mind, if it comes up a lot, it could be an indication that the drive is reaching the end of its useful life. Probably nothing though. Indeterminate (talk) 10:57, 30 July 2009 (UTC)

I skip these scans and have noticed no ill effects. Of course, your mileage may vary. Tempshill (talk) 19:31, 30 July 2009 (UTC)

Advantages and Disadvantages of Window Vista Ultimate

Can anyone tell me what is the advantages and disadvantages of window vista ultimate ? wait for your reply ya~ tq —Preceding unsigned comment added by Bebezaii (talk • contribs) 11:50, 30 July 2009 (UTC)

Advantages and disadvantages of WVU as compared with what, exactly? -- Hoary (talk) 12:11, 30 July 2009 (UTC)

In comparison to other vista editions see http://www.microsoft.com/windows/windows-vista/compare-editions/default.aspx 83.100.250.79 (talk) 13:09, 30 July 2009 (UTC)

The only disadvantage compared to other Vista editions is that it is more expensive, and maybe you won't really use the extra stuff you are paying for. (See the comparison link above.) --98.217.14.211 (talk) 14:02, 30 July 2009 (UTC)

It probably takes up more disk space too. (a few percent perhaps?) - I haven't got any exact figures on that...83.100.250.79 (talk) 14:33, 30 July 2009 (UTC)

I think the correct answer is not very much when compared to Windows Vista Professional Edition. Rjwilmsi 20:38, 31 July 2009 (UTC)

A freeware suite for Windows XP

I've already got OpenOffice installed. What other free software is worth installing for the general user please? 78.149.172.96 (talk) 12:01, 30 July 2009 (UTC)

I find OpenOffice Calc agonizingly slow for the kind of work I most often want to do with it and have taken to using Gnumeric instead. In my case it's not for Windows XP or indeed Windows anything, but I suppose that the "platform" doesn't matter. Other free software for Windows? IrfanView, and of course some alternative to Internet Explorer (I have found K-meleon a lot faster than Firefox). And the Gimp. -- Hoary (talk) 12:09, 30 July 2009 (UTC)

What does the general user want to be able to do? And do you mean free gratis or free libre? Algebraist 12:19, 30 July 2009 (UTC)

This list might be of interest to you: 40 free Windows apps. — QuantumEleven 12:23, 30 July 2009 (UTC)

VLC media player to play audio and video; Mozilla Firefox to browse the web (and/or Google Chrome); Mozilla Thunderbird for email; GIMP for editing pictures; Inkscape to edit diagrams, maps, posters etc.; Adobe Reader or Foxit Reader to read PDF files and FreePDF-xp to create them; AVG free for anti virus; Audacity to edit sound files and Avidemux to edit video; TUGZip to read and write zip files and the like; InfraRecorder to burn CDs and DVDs; Spotify to listen to music online; uTorrent for bittorrenting; Filezilla for FTP; Spybot search and destroy to fight spyware; Scribus for desktop publishing; emule for file sharing; and Google Earth and NASA Worldwind for maps and stuff. -- Finlay McWalter Talk 12:50, 30 July 2009 (UTC)

HandBrake+DVD Decrypter to backup your legally owned DVDs; Password safe to store your passwords. -- Finlay McWalter • Talk 12:58, 30 July 2009 (UTC)

Celestia is a fun science toy. It's a really slick 3D astronomy simulator that lets you fly around the universe (accurately representing distances, if not travel-times). Nimur (talk) 15:05, 30 July 2009 (UTC)

For audio and video I would suggest Media Player Classic with ffdshow // 21:55, 30 July 2009 (UTC)

Mp3tag for tagging MP3 files; TeamViewer for remote desktop; Recuva for file recovery; MyPhoneExplorer for my Sony phone (the Sony app sux); CDBurnerXP for CD/DVD authoring; GSpot to identify video codecs. ---— Gadget850 (Ed) ^talk 22:28, 30 July 2009 (UTC)

If you use facebook or twitter a lot, flock is a browser you might want to try. If you want to rip your CD collection and move your music to your PC, you will find Exact Audio Copy useful, possibly in combination with the FLAC software. If you want to tag mp3 files, and hate iTunes and similar programs that want to take charge of your entire media collection, foobar2000 might be the media player for you. I wasn't aware of Mp3tag, thanks Gadget850, I will want to try that one out. If you want to compress and decompress files and folders, 7-zip is useful. I wasn't aware of TUGZip either, thanks Finlay McWalter, I'll try that one out too! --NorwegianBlue ^talk 17:38, 31 July 2009 (UTC)

Solaris Operating System

Can anyone tell me what is Solaris Operating System?? What is the functionality of it? —Preceding unsigned comment added by Bebezaii (talk • contribs) 14:16, 30 July 2009 (UTC)

Solaris (operating system). --LarryMac | Talk 14:21, 30 July 2009 (UTC)

See also Comparison of operating systems and (if you're a technical type) Comparison of operating system kernels. -- 128.104.112.100 (talk) 20:25, 30 July 2009 (UTC)

Solaris is the largest (by market-share) true Unix platform that is commercially marketed. Unix is the operating system which inspired Linux; Solaris is one version that is designed and marketed by Sun Microsystems. Solaris had particularly strong support for Sun's hardware (espcially the SPARC processor series); it was primarily designed to support extremely high-end server and mainfraim systems, though its most recent incarnations are suitable for use on desktop and personal workstations as well.

Because of recent business changes (Sun was acquired by Oracle Corporation), as well as the increasing popularity of free Linux (and Unix systems like OpenBSD), it is not clear what the future holds for Solaris. Most of the system was released as OpenSolaris, a free, free version, in 2007; it is very likely that for this reason some incarnations of Solaris will continue to live on in enterprise environments. Nimur (talk) 01:22, 31 July 2009 (UTC)

Cost of video streaming

Recently, I read that one hour of video streaming costs 0,25c. Is that correct? Since I am constantly in YouTube, I have caused them cost of some thousand dollars...--Quest09 (talk) 18:34, 30 July 2009 (UTC)

Uh, what? The cost of the bandwidth, of course, might be counted but that's almost infinitesimal for a site as large as Youtube. I've never heard of a site charging $0.25 per hour for streaming video, although it sounds like a plausible business model. But despite what they charge, no, it doesn't cost a webmaster 25 cents to stream an hour of video. ZS 18:47, 30 July 2009 (UTC)

Since YouTube has advertising on their pages (and in their videos), you're not costing them the full cost of streaming video to you. Ideally, they should be making more money from showing you the advertisements than it costs to stream the video. I recall hearing that the YouTube division of Google is not yet profitable (that is, their total costs are more than their total revenues), but I'm sure they're looking into ways of narrowing that gap. -- 128.104.112.100 (talk) 20:23, 30 July 2009 (UTC)

It really depends on how you want to measure costs. In some sense, the enterprise scale system costs a fixed amount to operate, whether it is serving a video or sitting idly and warming a server room. However, this is not actually an accurate representation of the way that enterprise business data centers work in 2009 - a modern content delivery network can be outsourced, and can bill based on actual usage statistics. The price point that a CDN will charge an organization is going to vary widely depending on what is actually contractually delivered. (You can think of this as renting a percentage of a data center for each second that it is being used; and closely monitoring to make sure that every moment, you only rent as many servers as you actually use). I believe that Google does not choose to outsource, but instead runs its own CDN and data centers internally; that means it is harder to put a precise number on their costs. Even if such a number exists, it is highly proprietary market data, so it is unlikely that the estimates you hear quoted are accurate. Nimur (talk) 01:29, 31 July 2009 (UTC)

What if it really was .25 cents (as in, a quarter of a penny) as the OP originally stated... --66.195.232.121 (talk) 17:10, 31 July 2009 (UTC)

I just came up an advertisement for http:// streamapi dot com / pricing.do One hour of 256 kbit costs 5c and one hour of "Full HD" costs 20c. Of course, that's just some random advertisement I saw. It is a white-label solution so it probably as expensive as it gets. Kushal (talk) 20:00, 31 July 2009 (UTC)

Note that these estimates vary by a factor of about 100x (20 cents to 0.25 cents) - that gives you an idea of the uncertainty in price estimation! In either case, the original poster brings up the valid point - your "free online viewing" experience is being heavily subsidized by somebody else. Is Google losing money on the video transactions? Or are they recuperating their losses by charging advertisers? If so, are advertisers really returning on their investment at such a steep price? These are all valid questions; but if you consider the cost of operating a television broadcast antenna, cable television network, etc., you might get some perspective. For the last fifty or hundred years, people have been paying top dollar to influence mass media. This sends up a red flag of paranoia in me - why is it so important that I see these people's productions, that they will spend so much money on them? Nimur (talk) 00:01, 1 August 2009 (UTC)

July 31

WP:CRYSTAL

How Wiki came up with the idiom Wiki is not a crystal ball meaning Wiki does not calculate futue events. Crystal is just a gem, so what does crystal have anything to do with guestimating?--69.228.145.50 (talk) 00:29, 31 July 2009 (UTC)

See Crystal ball. --Tagishsimon (talk) 00:35, 31 July 2009 (UTC)

Image a usb memory stick

I am looking for a program that can raw dump an entire USB memory stick to a single file - without adding any of its own crap to the image. As there any software that does it? I also want to be able to write the image back.--155.144.40.31 (talk) 01:33, 31 July 2009 (UTC)

'dd if=/dev/yourusbstick of=usbimage' should do it on linux. Reverse the input file and output file to write it back, bit for bit both ways. --M^ask? 01:37, 31 July 2009 (UTC)

If you're not fortunate enough to be a linux user, this site has a long list of disk imaging tools. Most of them are bootable cds, probably not what you want, but this program sounds like it'll backup a usb drive to an image file. Indeterminate (talk) 01:38, 31 July 2009 (UTC)

I ended up getting cygwin so I could just do "dd if=/dev/sdb of=cygdrive/c/dump.raw" Thanks anyway!--155.144.40.31 (talk) 01:44, 31 July 2009 (UTC)

WinImage can do this // 14:57, 31 July 2009 (UTC)

SEO Optimization: URLs

Hi All,

When it comes to optimizing urls, does it HAVE to be the page name containing the keywords, or will something in the path be just as effective? Example

www.mysite.com/somecategory/file-name-with-keywords.htm

as opposed to:

www.mysite.com/key-words-here/2.htm

Will it make a substantial difference going from one to the other?

Thanks in advance PrinzPH (talk) 03:03, 31 July 2009 (UTC)

That will depend entirely on the search engine you are optimizing for. Google does not publish its indexing and ranking methodology, so it is not possible to give you a definite answer for Google's system. In general, though - it is probably safe to say that a modern web-indexing search engine will use some information from the URL to estimate search relevance. Nimur (talk) 14:11, 31 July 2009 (UTC)

I see. My question really revolves around assuming that search engines do use the URL (the string itself), does really matter at what point in the string it occurs? PrinzPH (talk) 17:00, 31 July 2009 (UTC) EDIT: I just noticed my question is redundant (Search Engine Optimization Optimization? lol) :p PrinzPH (talk) 17:05, 31 July 2009 (UTC)

As I mentioned before, the answer to that question depends on which search engine you intend to optimize results for. Since no commercial search engine publishes its algorithms, it is not possible to accurately answer your question. Here is Google's SEO guidelines. Note that Google does not look too kindly on the concept of "Search Engine Optimization" - they prefer that you organize your site properly and make it easy to index and crawl; and let them decide how you rank. Ultimately, that is how search engines work - somebody else decides (or writes an algorithm to decide) how the pages rank, and they do not have to tell you why they made that ranking. This lack of openness was the primary reason that Wikimedia sought to develop Wikia Search, an open-source search engine, with published ranking methods and algorithms, and community intervention. However, the project did not perform, very well, and is no longer active. Nimur (talk) 00:09, 1 August 2009 (UTC)

Strange network behavior

So I'm visiting my parents' place for a couple of days and they had their internet cancelled for the summer. A neighbor has kindly allowed me to use their wireless next door, and the last time I used it I could access it from over half the rooms in the house.

This time around I could barely access it at all. For about 5 minutes, I could access google.com, and it was quite fast and responsive, but NO other sites would work at all. Meanwhile I could do Google searches to my heart's content, so I simply gave up.

Then I disabled 802.11n and connected with 802.11g. A little better, but most sites still don't work most of the time. google.com doesn't work anymore, so my previous success must have been a coincidence right? Well... I ssh'd into my work machine and tunneled VNC through that. The VNC is nice and responsive (as much as VNC typically is), in fact I'm typing this question into Firefox on my work computer through my VNC-over-SSH session.

I left a ping -t (in Windows) running for about 10 minutes to the machine I ssh'd into and got a 95% packet loss. Meanwhile the VNC session has been perfectly responsive the whole time, including various other things I had going on in my little Putty SSH session at the command line.

Can anyone explain this behavior, why I'm getting such a poor ping response while my VNC session remains perfectly fine (from what I can tell)? If the wireless is spotty, wouldn't that trigger wireless retransmits that are invisible to the ICMP layer? If these retransmits are taking too long and the ping is timing out anyways, why is my VNC session still so responsive? If it's a QoS thing where my SSH stuff is getting through at the expense of ICMP stuff, then why is most of my web traffic getting blocked when no VNC is running? These should hopefully give you an idea of my network knowledge--or lack thereof. Generally speaking, why is there such a huge reliability gap (perfect.....abysmal) between my VNC-over-SSH to my work computer and everything else I've tried?

I also tried OpenDNS with virtually identical results (not that that would explain the ping/VNC disparity).

Thanks. --Silvaran (talk) 03:22, 31 July 2009 (UTC)

what is the ping response with URL vs IP? use yahoo and not google as they have blocked pinging their servers. you can also try to uninstall and reinstall the network driver for your wireless. Then check the connection. Ivtv (talk) 05:19, 31 July 2009 (UTC)

How mysterious! Since an SSH tunnel works fine, I would also guess some kind of QoS issue. My best guess would be some kind of malfunctioning traffic control or deep packet inspection firewall on the neighbors' wireless router or broadband modem. What about HTTPS/SSL? I'd guess that it probably works fine too - it might just be unencrypted traffic that gets throttled or dropped. Could the neighbors be doing some heavy torrenting? Even combined with QoS, it seems unlikely that it could cause the problem, but hrm. As far as solutions go, my #1 suggestion would be to get the neighbors to reset their router & modem. I guess that might be a little rude to say to them...

Oh, you could also try a traceroute to a few different sites, see if it always drops out at a certain point. That way, if you can ping your neighbor's router and modem easily, you can narrow down the issue. Yeah, that's probably the best sleuthy solution. Indeterminate (talk) 11:26, 31 July 2009 (UTC)

Thanks for the suggestions! I'm grabbing nmap now, though I'm not positive what kinds of info it will give me. I can't get to the router web page very reliably (and the high SSH tunnel reliability won't help that!), so I don't think a tracepath would help, but I'll give it a shot. The neighbors are actually away on vacation for awhile, so I'm thinking what I might try and do is, if I can figure out the router web page's password and get there reliably enough for a few minutes, I'll change the WPA2 key and see if that fixes things. If so, I'll change it back, and suggest the owner change it when I get a chance to talk to him next. Thanks again! --Silvaran (talk) 14:16, 31 July 2009 (UTC)

No go on the router web page stuff, I can't figure out the password, nmap can't even detect it (but still gives me a fingerprint so its connection attempts must have been successful), I'll see how it works for my neighbor once he gets back. Having my SSH tunnel work virtually 100% of the time and everything else work only 1% of the time is really baffling though... --Silvaran (talk) 14:16, 31 July 2009 (UTC)

Saving response for ping command in C

I know that with system("ping machinename") I can ping a machine in C. i'd like to save that output to a char array variable if possible. How would I do that? (if you could write up/copy paste some quick code, I'd appreciate it). Also, this isn't homework :). Chris M. (talk) 14:24, 31 July 2009 (UTC)

You can dump the output to a log file:

system("ping machinename > pingResult.log");

FILE* f = fopen("pingResult.log", "r");

// ... read and parse log file

Thanks, that worked exactly as I hoped. Chris M. (talk) 14:43, 31 July 2009 (UTC)

Ack, no, bad idea. There are a million ways that can fail: if the current directory isn't writable, if the file isn't writable, if the user has a file by that name that they don't want to lose, if two copies of your program are running concurrently in the same directory, if your program is running with elevated privileges and someone creates a symlink or exploits the system-fopen race... just don't do it. Use popen:

          FILE* f = popen("ping machinename", "r");

          // ... read and parse output

In Visual C++ it's called _popen instead of popen. You still need to sanitize the machinename if you got it from a source you don't trust. -- BenRG (talk) 21:28, 31 July 2009 (UTC)

Indeed. And it's also very wise to supply an absolute path for ping (e.g. /bin/ping). If you're going to be doing a lot of pinging, and need more control than the command-line ping executable can give, skipping popen and using a dedicated ICMP or ping library (or hand-writing it with SOCK_RAW/IPPROTO_ICMP, if you really must) like liboping (which Debian ships) might be for you. -- Finlay McWalter • Talk 21:42, 31 July 2009 (UTC)

Or, you can set up a named pipe, if you are on Unix, and open the pipe without ever writing to disk. Nimur (talk) 14:30, 31 July 2009 (UTC)

vista user pic

is there a way to ged rid of that bloody pic every user gets assigned in windows since xp to vista ??? i mean that there was no pic at all —Preceding unsigned comment added by 77.35.47.159 (talk) 14:36, 31 July 2009 (UTC)

One easy solution is to assign all users a blank, transparent PNG file. You will never see any image logos for users; and you don't have to spend a lot of time mucking around with complicated settings. Here is a 1x1 pixel transparent PNG that will do the trick. [15], and this Microsoft page explains how to set the user's picture. Nimur (talk) 14:58, 31 July 2009 (UTC)

diagnosing monitor trouble

A while ago my laptop began to have a problem where after being off for a while and then turning it on, the screen image would be flickery and then often go out. Once it went out there would still be an image on the screen, but with no illumination so it was almost impossible to see. This led me to believe there was a problem with the monitor's backlight. The only way to get it to work again would be to turn the monitor off and back on (the quickest way was to put it in stand by mode). The problem seemed to go away as the monitor was on for longer, so after a few tries it would work better, and then once it was on for a few minutes straight it would be fine until the next time I turned it off. Over a few weeks this issue got worse and worse until it became unusable. I connected it to an external monitor, which worked with no problem. I've been using it like that for a few months since I've been too lazy to do anything about it. Then yesterday I suddenly started having the same issue with the external monitor. The external monitor is an LCD as well. Is this a common enough problem that it's conceivable I'm having the same issue with two different monitors in the span of 6 months or is there something with the computer that could cause this? Rckrone (talk) 17:57, 31 July 2009 (UTC)

I had an LCD monitor (Samsung) with the exact same problem. After doing some online research, I found that it was due to a capacitor overheating (it can get pretty hot in my study during summer, which explains why the monitor worked just fine in winter/early spring/late fall). After replacing the capacitor (a half an hour job) the problem went away. If your monitor/laptop is a Samsung, that's likely your problem as well, but, of course, it could be a million other things.—Ëzhiki (Igels Hérissonovich Ïzhakoff-Amursky) • (yo?); 18:03, July 31, 2009 (UTC)

External HDD question

I think I know the answer to the question I am going to ask, but I'm gonna ask it anyway, just to confirm.

What is the worst that could happen to an external HDD (or the data on it) if it is connected simultaneously to two computers? The HDD in question has two connections (USB and eSATA)—if the drive is connected to a running PC via USB and also to another running PC via eSATA, what could the consequences be? The HDD contains a repository of data both PCs need to access, and neither PC is expected to update the data (not often anyway).

And yes, I know I can just share the drive over the network, so both PCs would have access to it no problem. I am just curious about this alternative approach (if only for access speed reasons). Thanks.—Ëzhiki (Igels Hérissonovich Ïzhakoff-Amursky) • (yo?); 17:58, July 31, 2009 (UTC)

Hmm... I'm not a expert in this, but I would assume it would work like a normal HDD. If a file is locked, you can't write to it, so there would be no corruption. Maybe someone else knows more? Thanks. AHRtbA== ^Talk 18:10, 31 July 2009 (UTC)

I would imagine that the controller inside a consumer external HDD with two interfaces will only allow one or t'other to be active at a given time; that it'll ignore the other altogether. In the event that it does support both, I'd guess it would work like a multi-interface storage area network device - it deals only in reads and writes of whole blocks (LBAs), and maintains a queue for reads and writes, actioning only one at a time. Almost all filesystems expect that they're the only user of a given block level device, and two such filesystems blindly accessing the same block level storage in this way isn't something they know how to deal with, so there will be terrible corruption and total (cache-related) inconsistency. So, in short, it won't work, and if it does, don't do it. -- Finlay McWalter • Talk 18:06, 31 July 2009 (UTC)

Well, this one isn't a consumer-oriented HDD; it's industrial (and quite expensive), so it'd be silly to risk frying it with an experiment like this. The whole inquiry was just unbridled curiosity speaking. Still, if I had a cheap HDD with two interfaces, I'd try it out just for kicks, to see what happens :) Thanks anyway!—Ëzhiki (Igels Hérissonovich Ïzhakoff-Amursky) • (yo?); 18:16, July 31, 2009 (UTC)

I would certainly consider it defective if simply plugging in two interface cables actually broke the thing. I should qualify my above slightly: if there were two partitions on the disk (assuming concurrent access was supported) and you arranged it for one computer to access the first, and the other the second, then that wouldn't be a logical problem. Performance-wise it would be a catastrophe, however, as the two computers disk-scheduling schemes would fight with one another, causing the drive head to perform big seeks repeatedly, dancing inefficiently to serve two selfish masters. -- Finlay McWalter • Talk 18:28, 31 July 2009 (UTC)

The matters are complicated by the fact that it's actually two (physical) drives in a RAID1 configuration (one logical drive). At any rate, I have no inclination of moving almost two terabytes of data elsewhere (in case they become corrupted) just to try out a silly experiment like this :) It would be most interesting to see how badly the performance would be hit, though. Cheers,—Ëzhiki (Igels Hérissonovich Ïzhakoff-Amursky) • (yo?); 18:39, July 31, 2009 (UTC)

Don't worry, there's absolutely no chance it would do anything interesting. Maybe there are external drives with multiple USB ports or multiple eSATA ports that are designed for concurrent block-level use, though I doubt it. But using two different interface standards to hook up two computers is obviously a hack, and there's no way they'd implement all the tricky arbitration logic that would be needed to support that hack, especially since in the vast majority of cases the result of all that effort would be to corrupt the file system and lose customers' data. -- BenRG (talk) 21:05, 31 July 2009 (UTC)

How to use MediaWiki PAGENAMEE for custom page name?

I know that in MediaWiki, they have two variable expansions, {{PAGENAME}} and {{PAGENAMEE}}, where the second one is the first one with special characters URL-encoded, and spaces turned into underscores. However, suppose I want to make a template that allows people to link to an external wiki outside of the Wikipedia family using a direct URL link (since it's a wiki using MediaWiki, I need to URL-encode page names in the URL when I link it), but I want to allow people to specify the page name as a normal page name (i.e. with spaces and special characters). So my question is: is there some special MediaWiki function that performs the exact same transformation as {{PAGENAME}} to {{PAGENAMEE}}, but on a custom string. Thanks, --71.106.173.110 (talk) 18:21, 31 July 2009 (UTC)

Mobile phone, voice recognition for calling

I have a Sony Ericsson W595 phone which I very often use with a bluetooth headset, and the first thing I did after buying it, was to try out the voice recognition feature for making calls. I recorded commands such as "Call Erik", "Call Ellen", etc. (I used the Norwegian word for call - Ring - and these are not the actual names). I did this for about ten or fifteen of my contacts. It worked beautifully. Beautifully, that is, in the quiet room where I was when I did the exercise. When I need the feature, however, it's a disaster. Outdoors, on the metro, when I'm running -- it hardly ever works. My question is - what should I do to make the feature usable?. My first thoughts are: don't say "Call" before the name of the contact, and keep the number of contacts that I use the feature for to a minimum. Any other suggestions? --NorwegianBlue ^talk 18:45, 31 July 2009 (UTC)

Try recording the commands when you're in a noisy environment. --LarryMac | Talk 18:51, 31 July 2009 (UTC)

Yes, I've thought of that, but I haven't tried it. The trouble is — I fear — that the ambient noise when I'm running, when I'm on the metro, when I'm in my car, when I'm in a shopping mall etc., are very different. I have, too, thought of making silly noises, whistling, gargling, singing falling and rising tones etc. to maximize the difference between the audio signatures of each contact. But that would really make people think I'm a lunatic. (I'm oldish, I don't really care all that much what people think, but still, there's a limit...). I would very much like this feature to work, because I would have used it a lot, especially when running (which I do for about an hour every day, on my way to work and back home in the evening). --NorwegianBlue ^talk 20:08, 31 July 2009 (UTC)

My daughter just arrived when I was typing my previous entry, and asked if I had used the bluetooth headset when recording the commands, and the answer is no, I used the phone's mike. I'll re-record the entries with the bluetooth headset, and without the Ring before the names. I'd still like to hear if anyone has experience in using voice-activated calls for more than a couple of contacts, though. --NorwegianBlue ^talk 20:21, 31 July 2009 (UTC)

Indirect sharing of contact info

On what social networking sites, if any, can I create a list of friends who can share my private profile with people I don't know, without allowing those friends to share the right to share the profile? NeonMerlin 20:37, 31 July 2009 (UTC)

Just to clarify, what you want is something like a way to set up specific groups that have "friends of friends" access, in the Facebook parlance? --98.217.14.211 (talk) 21:59, 31 July 2009 (UTC)

Note that this strategy is subject to the analog hole - (or rather, the digital hole). As soon as your data becomes viewable to others, they can copy it to some other unprotected system, and share it with others. Any copy-protection scheme is invariably prone to fail, because free information will proliferate. Such a system only functions as long as the data remains inside the closed system - which, by definition, is not closed, because you intend to allow "friends of friends" to view your data. You cannot vet these people for security clearance unless they are already in your "friends" group. Even then, you are assuming on good faith that they will not proliferate your data outside of the system you have asked them to use. I'm ranting here, but I'm still baffled how this minor bit of logic fails to register with the vast majority of Social Network users and designers. Nimur (talk) 00:12, 1 August 2009 (UTC)

But what they copy and share will be a static snapshot that can't be updated unless it's copied and shared again. So if you start getting e-mail spam and can find the "friend" responsible, you can cut them off and change your address. NeonMerlin 06:23, 1 August 2009 (UTC)

How to save a video clip to hard disk

How can I save the video clip here http://news.bbc.co.uk/1/hi/business/8173285.stm to hard disk? My normal method of finding the .flv file in the cache does not work. 89.243.180.82 (talk) 20:41, 31 July 2009 (UTC)

BBC News has switched over from Realplayer to the same technology as BBC iPlayer; it uses a transport (and, it seems, encryption) mechanism that's much more sophisticated than the simple flash movie player used by, for example, YouTube. I'm not aware of any means of permanently storing iPlayer content. People in the UK can temporarily store iPlayer content with BBC iPlayer Desktop, but I don't know if that extends to video embedded in non-iPlayer pages, like BBC News. -- Finlay McWalter • Talk 21:49, 31 July 2009 (UTC)

get_iplayer http://linuxcentre.net/getiplayer/ 87.194.213.98 (talk) 22:20, 31 July 2009 (UTC)

August 1

Amazon.co.uk, wish-list, Amazon's privacy policy

I just googled my own name (yeah, I'm bored, I've had a beer or three, my wife has longer holidays than I have and visits her parents, I'm alone etc.). As far as I know, I'm the only person on our planet with my exact name, and whaddayaknow: On page five or six of the search, amazon.co.uk kindly provides a wish-list for {My Name}. WTF is going on??? I've bought many books, both from amazon.com and amazon.co.uk. The list was relevant, I might indeed have liked to read the books that were suggested. I hate to admit it, but I don't always read all the fine print when I register on a reputable site. Skim through it -- yes, spend half an hour reading every detail -- no. What have I missed, and is there any way I could disable this blatant breach of my privacy? --NorwegianBlue ^talk 01:31, 1 August 2009 (UTC)

I think they make their wish lists public by default, the idea being (I guess) that you might want to send it to friends/family that don't already have amazon accounts. Still, not very friendly. They should at least ask first. I don't have an amazon.co.uk account, but on my amazon.com account, if you log in and click on the wish list in question, it should have a little box on the left-hand side of the window, with things like "This list is public. This is your default list.", etc. If you look down a little ways, there should be a button that says "Make this list private". IMO, they don't really make it easy to find. Indeterminate (talk) 01:59, 1 August 2009 (UTC)

Thanks. I found it. Personalisation → Wish list → Combo-box "This list will be viewable by:". Default is "Anyone who searches for me.". Still furious! --NorwegianBlue ^talk 09:06, 1 August 2009 (UTC)

On a side note as I read this...Google your email. watch what happens. That should pre occupy your paranoia :P 142.176.13.22 (talk) 02:35, 1 August 2009 (UTC)

You certainly managed to stir my paranoia, but... you're kidding, no? Which email sevice are you referring to? Do you have a source? I just googled my previous email address, which I've used for many years, but recently abandoned because of spam. The only thing that turned up was "Do you mean" {similar-address}@{emailservice}.com. I've heard stories about very unpleasant stuff turning up when people google their own national identification number. I'm reluctant to do that experiment, however, because google stores my searches. Might do it using tor (anonymity network), though, would that be safe? --NorwegianBlue ^talk 09:06, 1 August 2009 (UTC)

Every had to put your email to "join" a site to get access to something you needed from it? Ever did the same, to comment or answer a question on a strange forum? Ever given an answer on Yahoo Answers, good enough for some fake forum to scrape it? (the ones who scrape via RSS get the email ID, not the Nickname). In the old days you'd get one email address from your ISP, made up as some version of your real name and no choice about it. (Or you used your own, figuring it's more professional for work emails than being called fghjklj@somemail.com).

Happy hunting. Maybe get one of these useful shiny hats first. - KoolerStill (talk) 09:26, 1 August 2009 (UTC)

As stated, I've had a huge spam problem which forced me to transfer all my mail from one account to another (fake emails that appeared to come from me, with autoreplies drowning my inbox). Nevertheless, there were no ghits for my old address. BTW, after the spam problem, I've taken the following strategy: I have a couple of domain names with associated email addresses that I can redirect. When I need to register somewhere, I use an address that I create for that site only. If the address is compromised, I'll know who did it, and the problem is easily corrected. --NorwegianBlue ^talk 10:51, 1 August 2009 (UTC)

Currently-working robot certificate authorities?

Hey all,

All the CAs linked from robot certificate authority seem to be down/abandoned/otherwise not working, as do all those I can find via the first few pages of a Google search. Does anyone know of any that are still active?

Thanks, --Aseld ^talk 01:51, 1 August 2009 (UTC)

Finding compatible graphics card for Acer Aspire

I have an Acer Aspire 5738Z (http://www.acer.co.uk/acer-v2/seu30e.do?kcond61e.c2att101=56845&LanguageISOCtxParam=en&link=ln400e&CountryISOCtxParam=UK&acond125e=56845&sp=page18e&ctx1g.c2att92=122&ctx2.c2att1=17&ctx1.att21k=1&CRC=3755713286) which has a JV50 motherboard and is currently using integrated graphics. I would like to upgrade the graphics. How do I find which graphics cards are compatible? ----Seans Potato Business 07:13, 1 August 2009 (UTC)

You're not going to find any. Only a limited number of very premium laptops have an upgradeable videocard, due to size, heat and power issues, as well as proprietary connections and components. That said, this machine seems to have quite a powerful video system, so I'm curious why you feel the need to upgrade it. If it's performance issues, proper system maintenance would probably make the most difference. --M^ask? 09:03, 1 August 2009 (UTC)

From Sisoft Sandra, I have deterined:

PEG Slot J6B2 (6h) : PCIe 32-bit +5V +3.3V Full-Length Available

PCI Express Slot J6B1 (7h) : PCIe 32-bit +5V +3.3V Full-Length Used

PCI Express Slot J6D1 (8h) : PCIe 32-bit +5V +3.3V Full-Length Available

PCI Express Slot J8B3 (9h) : PCIe 32-bit +5V +3.3V Full-Length Used

PCI Express Slot J8D1 (Ah) : PCIe 32-bit +5V +3.3V Full-Length Available

PCI Express Slot J7B1 (Ah) : PCIe 32-bit +5V +3.3V Full-Length Available

PCI Express Slot 6 (Ah) : PCIe 32-bit +5V +3.3V Full-Length Available

- doesn't this mean that I have a PCI-e slot available?

My laptop is available with at least two options with respect to graphics and I have the lesser of those two options (integrated Intel 4500M with 64 MB dedicated VRAM, as opposed to NVIDIA GeForce G105M with 512 MB dedicated DDR2). I'm guessing you thought I had the latter? ----Seans Potato Business 12:27, 1 August 2009 (UTC)

Sandra reports what the PCI bridge controller reports to it; those are logical ports, which on an integrated laptop chipset don't always correspond with physical pinouts on the southbridge (some are instead on-die pci connections to other integrated peripherals. Moreover, those ports that are pinned out of the southbridge package aren't necessary connected to any physical header, and in laptops and small form factor systems (which don't have room for the PCI headers, never mind actual PCI cards) most are just terminated by the system builder to pullups. The only way to know what is actually mapped to a physical PCI header is to check the underside. Acer laptops have all their removable components accessible via panels on the bottom, which are labeled with (moderately) clear icons. My own Acer, a travelmate, only has panels for memory and the hard disk, although I've seen others that have one for the WiFi card as well. I've personally never seen an Acer (I've only seen mid-range ones, not the Ferrari ones) that had a removable graphics adapter. -- Finlay McWalter • Talk 12:42, 1 August 2009 (UTC)

windows downloads

I was told to download Windows NT4.0 service pack 3 from the microsoft website, but searching the site, it seems they only have service packs 2, 4 and 6. Does anyone know where I can find this service pack 3?

88.108.248.67 (talk) 10:58, 1 August 2009 (UTC)