Wikipedia:Reference desk/Archives/Computing/2007 February 21

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Computing desk
< February 20 << Jan | February | Mar >> February 22 >
Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.


February 21[edit]

Ethernet Plug Cable?[edit]

Hi there,

I was researching, and adding a "Broadband Telephone" onto my computer. I was required to find the boardband ethernet cable from the computer? Where is it? What is the colour of the plug? How many plugs down from the top of the CPU?

 Smcafirst | Chit-Chat  posted at 03:09, 21 February 2007 (UTC)

Ethernet cable (click image for bigger) --h2g2bob 23:18, 21 February 2007 (UTC)
It really depends on your computer, there isn't really anything that's specifically a "broadband ethernet", just a mis match of terms, what you are looking for is your ethernet or simply network port. Technically, it's called an Rj45 socket, kinda looks like a phone plug, the little type not the big type, and it should have 2 tiny lights above the hole, but when they are not illuminated they might not obviously look like little lights. Vespine 03:58, 21 February 2007 (UTC)
Also, the color does not matter at all. Freebytes

Virus Search Problem[edit]

So in doing an AVG virus search on my Windows XP computer, I was presented, after a few minutes of searching, with a menu that said "Unwanted Program While opening file: C:\\WINDOWS\Downloaded Program Files\pinstall.dll Adware.LookMe" (The "Adware.LookMe" was on the next line of the message; whether this is because it was separated by a space or because it wouldn't have fit on the line above - which was the case - I don't know.) At any rate. It asks me if I want to Ignore the "Unwanted Program", Move to Vault, or Add to Exceptions (meaning they wont bother me about it in searches to come.) I have no idea what I should do. I know dll files can be important, and I generally keep out of the WINDOWS folder, but otherwise I'm pretty clueless here. What should I do? Thanks, 70.108.199.130 05:09, 21 February 2007 (UTC)

It's an Adware, which doesn't qualify for virus but you still don't want it on your computer. I would move it to vault (or delete it manually). --antilivedT | C | G 05:25, 21 February 2007 (UTC)

Thanks a lot.

Encyclopedia software[edit]

Would anyone know of any sort of encyclopedia software (Preferably freeware, naturally) that is similar to and can be used in a similar fashion to Wikipedia and other wikis (For example; articles, internal-linking, search functionality and the like) but is chiefly offline and only for personal use? Thanks, --Knyght27 10:28, 21 February 2007 (UTC)

If you're comfortable with web servers, databases and the like (or are willing to learn), you could always install MediaWiki (the software that Wikipedia runs on) on your own computer. — Matt Eason (Talk &#149; Contribs) 10:55, 21 February 2007 (UTC)
Some people also like JSPWiki. (I don't; at least in the version that I'm saddled with using, it's not nearly as feature-rich as MediaWiki and its markup differs just enough to always leave me typing the wrong stuff.)
Atlant 12:34, 21 February 2007 (UTC)
Personal_wiki and Comparison_of_wiki_software may be useful. -- Diletante 23:14, 21 February 2007 (UTC)

Tracing IPs[edit]

I asked a question on the Wikipedia-help desk regarding tracking down the location of an IP address and was told:

If you go to an IP's talk page with messages on (it doesn't work if the talk page is a redlink) and click on WHOIS at the bottom of the page, it will tell you information about the IP. Sometimes it can be traced down to an individual school, city, or organisation, sometimes you don't get any more information than which contintent the IP's located on.

My next question is, what causes the variability in the available information? --Seans Potato Business 10:57, 21 February 2007 (UTC)

When an IP address is allocated, it may be allocated to a school, an organization, a company, a city, a country... anything. All you can see is who the IP address is allocated to. It is like trying to see who is living in a specific apartment in New York. If you go by the official records, you might get the management company that owns the apartment, you might get the landlord, you might get the guy who pays the rent but sublets it out... --Kainaw (talk) 13:18, 21 February 2007 (UTC)
It's not as dire as that, as you will get the ISP's location and not your location. Schools and educational institutes are a bit different, as I think a lot of them get special deals for their internet, and I think they sometimes do some peering too. You can't really trust the information to be accurate, except perhaps for the country - for example my DNS says I'm at Bath, but I'm really at Exeter. --h2g2bob 23:04, 21 February 2007 (UTC)

Representing | in BNF[edit]

Since the | is used to separate statements in BNF, how do you represent a | in BNF for something like the standard boolean "or" in most programming languages? --Kainaw (talk) 13:15, 21 February 2007 (UTC)

Usually literals in the grammar are set off in some fashion — with quotes, or italics, etc. — so that you can write any character in them without confusion. This can be used for whitespace, |, or whatever. (Consider Python's grammar with its indent tokens, and the example BNF grammar for BNF.) --Tardis 17:12, 21 February 2007 (UTC)
Thanks. I hadn't used quotes for any other literals because I use angle brackets for all non-literals. I just put quotes around the | and added a note a the bottom. --Kainaw (talk) 18:29, 21 February 2007 (UTC)
IF you are using the | in more than one place, it's better to add a new production
 <or>::= "|"
and then use <or> everywhere. If your formal BNF allows comments (e.g., if you are using yacc) put the comment in this one place.-Arch dude 01:03, 22 February 2007 (UTC)

Windows Operating System[edit]

In what programming language is Windows OS written 219.65.190.120 14:34, 21 February 2007 (UTC)

Most of it is C++, I'd say. yandman 14:42, 21 February 2007 (UTC)
C++ and C#, I believe. --Wirbelwindヴィルヴェルヴィント (talk) 15:28, 21 February 2007 (UTC)
Generally speaking, the kernel is in assembly language, DLLs are in C, and higher-level functionality is in C++. —LestatdeLioncourt 16:32, 21 February 2007 (UTC)
Not quite so. [1] [2]. The NT kernel (NT, 2k, XP, Vista; sources talk about earlier NTs, but it likely hasn't changed much) is mostly C, some C++, and a little assembly where it's needed. Most drivers and other important bits are probably in C, with the other stuff being mostly C++, but I can't be certain (i.e. can't find a source). Vista might use a little C#; they were originally playing up the idea that large swathes of the OS would be redone with C# code, but didn't go through with it. -- Consumed Crustacean (talk) 18:36, 21 February 2007 (UTC)
I thought that a lot of efficiency-important drivers in Windows were done in pure asm --frothT 19:39, 21 February 2007 (UTC)
Since most device drivers are limited by the I/O bandwidth, I doubt it; the cost of maintaining assembly code is too great for the small speed increase. --cesarb 22:01, 21 February 2007 (UTC)
Assembly language is not intrinsically faster nor smaller than C, etc. Poorly performing code and bloatware can be written in any language. Mostly, assembly language attracts programmers who obsess about the size and speed dimensions of engineering, and the choice of programmer has much more to do with the effectiveness of any solution than the language.
The overriding concern for most development is portability: That's why Windows NT, Linux, Apache, MySQL, Perl, and C compilers are all written in C, which provides an effective programmer the means to write portable, efficient (speed + size), and comprehensible code. Development time is also a significant concern, but portably-written code addresses that nicely—the first time the code is retargeted.
Only a few bits of NT are likely to be assembly: the handlers for dealing with specifics of the CPU, like page faults, CPU type detection (80386 vs. 80686), maybe select portions of interrupt handlers, and a few odds and ends dealing with the FPU and quirks of the CPU, like the page-edge-fault bug of the 80386. —EncMstr 22:52, 21 February 2007 (UTC)
The only area of intense assembly language program that I've seen anytime in the last few years is in 3D engines for video games. I remember a quote from John Carmack that went something like: Anyone can learn some ray tracing and opengl and pump out a 3D engine. When you wonder why yours gets 40FPS and the Quake engine is getting 80FPS, you'll have to learn assembly. --Kainaw (talk) 22:58, 21 February 2007 (UTC)
The Demoscene still makes use of it for purposes of size optimization, though that's pretty fringe programming. Check out some of the demos at [3] if you're bored enough. -- Consumed Crustacean (talk) 23:23, 21 February 2007 (UTC)
One nit: while I wish I could agree with you, the overriding concern in most projects (commercial ones, at least) is, sadly, not portability; it's not even in the top three. The overriding concern (driven by management) is time-to-market; #2 (driven by programmers) is doing as little work as possible; #3 is actually getting the code to work right; #4 might be maintainability. Maybe down at around #5 do a few dedicated programmers start worrying about portability...
(I'm not arguing with you to suggest that portability shouldn't be important; it certainly is important to me. But unfortunately large swaths of the rest of the industry do not agree with us.) —Steve Summit (talk) 04:46, 22 February 2007 (UTC)
Time to market is indeed a major incentive. And some, usually poorly organized (to put it politely) operations, do the 100 yard dash without considering what comes after getting there. That's where portability increasesdecreases time to market substantially. And I respectfully disagree with your #2: programmers don't get much consideration over how much trouble it is, not unless they're paid by the hour. #2 is usually functionality. Larger companies consider support costs as #3 (though I've worked at some where that's #2), smaller companies. Granted, most of my experience is for mass-market software, so that greatly skews the weighting of these factors. For custom software developed for a Ma & Pa operation: cost is almost always the overriding concern. —EncMstr 23:46, 23 February 2007 (UTC)
Also, nowadays CPUs are built with compiler optimization in mind, and it makes writing assembly code by hand much harder. ColourBurst 16:09, 2 March 2007 (UTC)
Well screw portability and the end user; ASM is tiny and fast and I like it >:{ --frothT 05:08, 22 February 2007 (UTC)
Yes. Fast.
waste_time:
push ecx
mov ecx, 1234567
do_the_wasting:
loop do_the_wasting
pop ecx
ret

global _start
_start:
call waste_time
mov edx, msglen
call waste_time
mov ecx, msg
call waste_time
mov ebx, 1
call waste_time
mov eax, 4
call waste_time
int 0x80
call waste_time

mov ebx, 0
call waste_time
mov eax, 1
int 0x80

jmp $
call waste_time
int 3
int 3
call waste_time
xor eax, eax
not eax
int eax

section .data
msg db "hello", 0xa
msglen equ $- msg
--wj32 talk | contribs 08:48, 22 February 2007 (UTC)
Doesn't look lik eit actually does anything.. --frothT 19:36, 22 February 2007 (UTC)
It's his counter-example. Splintercellguy 22:05, 22 February 2007 (UTC)
OK... well here's some C that's slow:
void do_nothing(int iterate) {
if(iterate<100) return do_nothing(iterate+1);
else return void;
}
iterate(0);
What does writing bad code have to do with the speed and efficiency of the language? Wj32 you can't possibly argue that ASM isn't fast; it's basically identical to the object code that every other programming language sends through the processor, but without the overhead --frothT 20:51, 23 February 2007 (UTC)
I think the point is that someone who isn't skilled can easily make very poor programs in assembly. Optimizing assembly requires a pretty good functioning knowledge of the microarchitecture in question, something about its internals, and a lot about its quirks. Someone familiar merely with the ISA and what it's intended to do (as opposed to what it actually does) may well fare worse than someone writing C, especially for big and complex ISAs like x86. Bugs in instructions, unexpected side-effects, potential data hazards, even microcoded instructions that end up being less efficient than a combination of other instructions are all things you have to recognize and deal with. Most C compilers contain fairly extensive optimization tables and periphery that do a lot to navigate all this, and frankly only a fairly skilled programmer will be able to glean a little bit of extra performance by writing some of their code in assembly.
More importantly, the extra development cost of writing and maintaining that may outweigh any performance advantage. I find it ironic that you use the adjectives speed and efficiency here, since from a coding, debugging, and maintenence standpoint, assembly is anything but. Even though it is possible to, say, implement an office suite entirely in assembly, the development and maintenence cost of doing so would be ridiculous, nevermind the fact that in such a sheer mass of code one would naturally expect to find a proliferation of bugs. Even if you had skilled assembly programmers, you'd end up with an unportable, unmaintainable monstrosity that costed many times what it would have if using other tools. There's little advantage in that. Now, for some low level portions of operating systems, it does sometimes make sense to write certain subroutines in assembly (and this is frequently done). However, you'll rarely see large modern OSes written entirely in assembly for roughly the same reasons you won't see Microsoft Office written in assembly. C has sometimes been called "the portable assembly", which I think gives a clue as to why it's a popular language for OSes. -- mattb @ 2007-02-23T21:08Z
Yes, you stated it quite well. —EncMstr 23:46, 23 February 2007 (UTC)
I believe almost all the open-source OS are written (mainly) in C. There are a couple of assembly OS like V2 and MenuetOS. My guess is most proprietary OS use C too.172.144.97.71 22:46, 26 February 2007 (UTC)

IPOD[edit]

Is it possible to bypass the feature on my Nano IPod and download or upload songs without having to delete everything first?

There are certain programmes, such as copypod, which allow you to copy the current files to your computer.... This would mean not losing files if you move to a new computer... However, I do not know of any other such programmes. Asics talk Editor review! 21:46, 21 February 2007 (UTC)
Yamipod (google it) is a good free one, if I understand what you are asking. Which I'm not sure I do, because I don't really get what you mean by itunes deleting everything. Perhaps the answer has something to do with your itunes settings. I don't know about the nano specifically, but my experience with other ipods is that your itunes comes with all sorts of funny settings that make it automatically upload and delete etc. If you go into Itunes preferences, you should be able to cancel automatic upload, which might solve the problem. You need another program, however, (Yamipod's the one I use) to download from the ipod to the computer. Itunes doesn't let you do this because they don't want to deal with all the copyright crap that might result from lots of people easily moving music or whatever from their ipod to someone else's computer. 70.108.199.130 06:33, 22 February 2007 (UTC)

Windows installer[edit]

The Windows installer on my computer is giving me a lot of trouble. Whenever I try to run Microsoft software, the installer launches and tells me it cannot locate the pro11.msi file. I know that this is because I manually deleted my Office 2003 folder from my Program Files folder after installing Office 2007 (for some reason, the Office 2003 uninstaller refused to run). How do I make this stop? —LestatdeLioncourt 16:20, 21 February 2007 (UTC)

Look around for the file on google (unlikely if its part of an office install or something) or check your office/widows CDs to see if any of them have the file, and if you find it, use browse and point the prompt at it. It's probably not going to shut up about it until you give it the file, or get tired of the prompt and format. Cyraan 18:01, 21 February 2007 (UTC)
A suggestion: Instead of deleting the program folder, use the Windows Add/Remove programs. Click Start, then Settings, then Control Panel. You will find an icon labled "Add/Remove Programs" and you should be able to find the program that you want. Deleting the program file folder will cause errors and difficulty installing if the program puts itself into the Windows registry. user:zylstra555

The Add/Remove programs panel invokes the uninstaller for Office 2003, which as I mentioned, refused ro run. I tried pointing the installer at the file it was asking for (I have it on the installation CD), but it still wouldn't shut up. Maybe I'll try cleaning up the registry... though I've had highly unpleasant experiences with that before. I think somehow the Office 2007 installer screwed up my machine, because I tried to install Office 2007 on my laptop, but then I found out that it needed at least XP SP2 (I have SP1), and now I can't run Office at all on my laptop (I also get the same prompt when launching any Microsoft product). Windows can be such a headache at times... —LestatdeLioncourt 20:09, 22 February 2007 (UTC)

Windows XP suxxorz[edit]

I accidentally clicked on my bottom menu (the one with the start menu, etc) and mistakenly dragged it to the right (dorsal) side of my screen. I can't get it back on the bottom. I once knew how to fix it... crap. Help meem! 69.81.50.3 18:21, 21 February 2007 (UTC)

Right-click it (make sure it's an "empty" part - ie not on one of the buttons or icons) and make sure 'Lock the Taskbar' is unchecked. Then click and drag it back to the bottom. Again, make sure you click on an empty bit before you drag. It's called the taskbar, by the way. — Matt Eason (Talk &#149; Contribs) 18:27, 21 February 2007 (UTC)

.rep[edit]

I've probably posted the question some time ago, but forgot how to watch the downloaded replays in StarCraft. Namely after throwing the .rep files to the maps folder I select Multiplayer, then Direct Cable Connection, then Create game, but see no such files. Suggestions? --Brand спойт 21:16, 21 February 2007 (UTC)

You have to find the file; for downloaded replays (from other players) they're in "Download" (oddly enough); ones you save from your own games should go in "Replays". Note that these are subdirectories of the "maps" directory; you may need to go "Up One Level" first if it starts you in, say, "BroodWar". --Tardis 00:29, 22 February 2007 (UTC)

Default font in Notepad[edit]

What is the default font in Notepad? 68.193.147.179 22:35, 21 February 2007 (UTC)

Fixedsys. Anchoress 22:44, 21 February 2007 (UTC)
Update: Not for every version though. Lucida Console is used for some versions of Windows; read the Fixedsys or Notepad article for more info. Anchoress 22:47, 21 February 2007 (UTC)
It's "System" on my Windows 98 SE. Check (or change) yours with Edit, Set Font. --h2g2bob 22:45, 21 February 2007 (UTC)
Was going to say it is Lucida Console on my XP machine but I clicked the wrong button on an edit conflict. I'm wondering it is clear to the op about ascii and notepad and how it does not save any formatting information? So default font is pretty irrelevant. Vespine 22:57, 21 February 2007 (UTC)
Well I'm running NT4.0 and my print test had Fixedsys printing as Courier New, and when I changed the font to Arial it printed as WYSIWYG. Anchoress 23:08, 21 February 2007 (UTC)
Vista uses Consolas ;)! JoshHolloway 22:32, 22 February 2007 (UTC)