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May 28

Another trivial pascal question

One tutorial I've been reading says that "Reciprocal calls wastes stacked much faster than recursive calls" - is this right ? I can't see why they would be different.

Also the statement

proceedure whatevername (variables etc here) ; forward ;

for setting up a later defined proceedure for reciprocal calls - this is just a directive to the compiler right - to prevent it getting confused - it has no major effect on the final compiled code?77.86.10.194 (talk) 02:37, 28 May 2009 (UTC)[reply]

See Tail recursion for why straight recursion can be much more efficient. And yes the forward declaration is just to make life easy for the first pass of the compiler, it shouldn't affect the code produced. Dmcq (talk) 08:02, 28 May 2009 (UTC)[reply]

Thanks. Tail recursion made sense of it. The tutotial just mentioned it in passing. I wasn't expecting any sort of optimisation on that sort of thing (as I'd never heard of tail recursion before).77.86.10.194 (talk) 11:20, 28 May 2009 (UTC)[reply]

I think the tutorial is wrong. I'm not sure what "reciprocal calls" is supposed to mean but I guess it means mutual recursion, in which case it's wrong to contrast it with "recursive calls", since mutual recursion is recursion too. Tail recursion optimization is not limited to self-recursive functions. An implementation might optimize only the self-recursive case, but there's no reason to expect that, unless the tutorial is geared to a specific implementation that happens to behave that way. -- BenRG (talk) 10:36, 28 May 2009 (UTC)[reply]

Thanks. In context the 'recursive calls' meant calls from procA to procA, and 'reciprocal calls' meant calls from A to B and also B to A, as you rightly infered/guessed. I would imagine that the writer is guessing that only self recursive calls are optimised - as you suggest...

(reply edited):Isn't it more difficult to tell if a mutually recursive call can be optimised - depending on whether the two calls use the same variables etc (I'm still trying to work it out).77.86.10.194 (talk) 11:31, 28 May 2009 (UTC)[reply]

What would normally happen is that one might be inlined in the other because it is small, and then the tail recursion optimisation is applied. It would not normally be considered worthwhile doing the optimisation where both are large routines. So yes a good optimising compiler would stick the two together in most of the important cases. Dmcq (talk) 15:07, 28 May 2009 (UTC)[reply]

The tail recursion optimization is virtually always worthwhile when you can do it. It is touchier when calling a function other than yourself, that's true. You can't usually tail recurse if there's some local state like an exception frame that needs to be torn down before you return, but when you're calling yourself you might be able to arrange to reuse the same exception frame. If you're using a caller-popped calling convention (like the one normally called the "C" convention on x86) then you can't call a function that takes more stack arguments than you did, which might be a problem in the mutually recursive case. If it's callee-popped (like the one called "Pascal") then this isn't a problem. I don't actually know whether x86 Pascal implementations use the Pascal convention. According to x86 calling conventions, Delphi uses a (different) callee-popped convention, but a web search suggests that Delphi doesn't do any tail-call optimization anyway. -- BenRG (talk) 21:08, 28 May 2009 (UTC)[reply]

Thanks - I guess that if using the 'replace call with jump' compiler method for tailend recursion it's quite possible that the return to the original proceedure call may happen in a different subrouting (ie Call A (A and B recursing each other) but the return conditions happen in B) - in this case it's best if the caller does the popping, rather than the callee(the subroutine).. because procB might be expecting more or less on the stack to pop than procA.?

I think I've least half understood anyway, which is better than 0. Thanks/77.86.10.194 (talk) 17:30, 29 May 2009 (UTC)[reply]

Wrong search redirection

Whenever I click on anything at the search results page, I am taken to some different website. The websites taken are stubs and nothing but advertisers (ex. [1], [2],etc.). It isn't that I am taken to them everytime, but that's 7/10 times. It doesn't matter I do the search from live.com or google.com, anycase I wound up at some spam website. 218.248.80.114 (talk) 05:01, 28 May 2009 (UTC)[reply]

Sounds like spyware. Shadowjams (talk) 06:28, 28 May 2009 (UTC)[reply]

Run a virus scan on your computer. If you don't have a virus scanner see list of antivirus software which lists free as well as commercial products. 62.78.198.48 (talk) 07:53, 28 May 2009 (UTC)[reply]

my guess would be that your hosts file has been compromised, and your winsock corrupted. As mentioned above, an AV program is important. You may want to look for a fixwinsock, or winsockfix program if you have a way to do that as well. In some minor cases, I have seen the command: "netsh winsock reset" (without quotes) make things a bit more functional. You may find this site helpful in finding tools and information. — Ched : ? 16:37, 28 May 2009 (UTC)[reply]

Are you sure you're not just seeing search engine spam? APL (talk) 17:41, 28 May 2009 (UTC)[reply]

I had this problem from clicking on two Wikipedia results, in Google. A third result (from the next page) seemingly identical to the first, came up with the correct Wikipedia page. Shortly afterwards I noticed the iexplore.exe process running (although I never use Internet Explorer) and it kept restarting after being forced to terminate, through Task Manager. A number of different virus scans showed nothing, but a scan with RootRepeal immediately showed various Trojans, and some DLL's with 35-character names beginning with UAC. Getting rid of these stopped both the site redirections and the background running of IE.KoolerStill (talk) 21:29, 28 May 2009 (UTC)[reply]

Randomly named DLL files are signs of infection by a Trojan (Or Trojans). Scans by Malwarebytes' Anti-Malware and SUPERAntiSpyware are needed immediately. This infection falls under adware/redirection Trojans. (Unless there are even more infections) Hosts file modification and/or Winsock corruption are possible. If the hosts file has been modified; delete it then replace it with either the MVPS hosts file or the HpHosts file to help prevent future infections. There are fixes available if Winsock has been corrupted. Finally, an effective anti-virus is required to help keep your computer secure. If you want a free one, try avast! or Avira AntiVir. --Xp54321^{(Hello! • Contribs)} 02:01, 29 May 2009 (UTC)[reply]

I agree all sudden strange behaviour warrants a virus or malware scan. Neither of those 2 mentioned above picked up the DLL files involved.They were "hidden to Windows API" and not in the file system, failing to show up even through the command line when searched by the name known after detection by RootRepeal. HijackThis also showed them, but did not allow removal. The Trojan appeared to have been downloaded by the first redirected search result, which was probably the result of page hijacking.(The machine had been freshly scanned and cleaned, and was being run without a firewall for testing purposes). The constant renewal of the IE process, I imagine, is connected to an attempt by the Trojan(s) to send data back to their "mothership".KoolerStill (talk) 09:29, 29 May 2009 (UTC)[reply]

Windows Sound Recorder

The Windows Sound Recorder (sndrec32.exe, if I remember correctly) in Windows XP had not changed much (if all) since Windows 95, or perhaps even since version 3.1. In Windows Vista, however, Microsoft improved it slightly when they removed the audio file duration limit (which was truly annoying!), and added support for WMA (with simple metadata, but at the same time they also removed support for all other formats, i.e. WAV files with different bitrates, channels etc.). However, all other changes were for the worse. Almost all additional features (such as effects, and simple merging of audio files) were removed. Now, the only button or menu item left is "Start/Stop recording"! Have Microsoft improved this extremely primitive sound recorder in Windows 7?--Andreas Rejbrand (talk) 17:02, 28 May 2009 (UTC)[reply]

Why even bother when the free and much better Audacity is available? --antilived^{T | C | G} 04:07, 29 May 2009 (UTC)[reply]

That's not a helpful answer. I don't know OP, hopfully someone with Windows 7 experience will come along soon and be able to tell you —Preceding unsigned comment added by 82.44.54.169 (talk) 04:28, 29 May 2009 (UTC)[reply]

And here I am, now rebooted to Windows 7! No, it looks exactly the same as the one in Vista. --antilived^{T | C | G} 04:45, 29 May 2009 (UTC)[reply]

OK, thanks! --Andreas Rejbrand (talk) 10:58, 29 May 2009 (UTC)[reply]

Resolved

Saving my favorites

If I'm getting a new PC and I have to transfer all data from the old one to the new one, can I do this with my 'favorites' from Windows Explorer? I guess there's a file somewhere that holds them all?Popcorn II (talk) 18:16, 28 May 2009 (UTC)[reply]

You probably mean "Windows Internet Explorer" (Windows Explorer is the name of the shell in Microsoft Windows, i.e. explorer.exe). If you use Windows Vista, this is very easy: all your favourites are located in the C:\Users\<User Name>\Favourites folder (just as documents are stored in ...\Documents, images in ...\Pictures, downloads in ...\Downloads and so on). --Andreas Rejbrand (talk) 18:29, 28 May 2009 (UTC)[reply]

Sorry, yes I mean Internet Explorer and I use XP.Popcorn II (talk) 18:55, 28 May 2009 (UTC)[reply]

For me, the folder with the links is located at "C:\Documents and Settings\YourUsernameHere\Favorites". Just copy and paste those onto a flashs tick and then from there onto you new computer. Thanks, 99.224.117.66 (talk) 20:09, 28 May 2009 (UTC)[reply]

Will do, thanksPopcorn II (talk) 20:45, 28 May 2009 (UTC)[reply]

error in installing

I have a pc with core 2 due processor and on it windows xp is installed.Now a days I have eperiened a problem with it .when i insert a flash derive and try to open it with double lick ,a message appear ," Error loading ,\RECYLER\S-5-3-42-28-------\jwgkvsq.vm.The speified module could not be found " But after right clik menu appear has first option as autoplay but it does not work ,but if click an other option " open " , it works. More ever ,when i try to install some programmes it does not work ,but i have instlled some of these programmes already. but now they do not work . Also —Preceding unsigned comment added by 119.154.35.156 (talk) 19:02, 28 May 2009 (UTC)[reply]

Backup important files and format it. Seems like it had been infected by some virus but was improperly removed. --antilived^{T | C | G} 04:06, 29 May 2009 (UTC)[reply]

Capturing video from a window

Resolved

I want some software for my Windows XP machine that will capture what occurs in a game window on the screen, to a video file. Last time I looked into this a couple of years ago, Camtasia Studio 4 seemed to do most of what I wanted; but it seemed expensive. This YouTube video of Starcraft II is of very high quality, just what I'd like - assuming it's a capture of something that takes place in a window. What do other people use for video capturing what occurs in a window? Tempshill (talk) 22:14, 28 May 2009 (UTC)[reply]

Check out Comparison_of_screencasting_software 161.222.160.8 (talk) 00:43, 29 May 2009 (UTC)[reply]

Perfect and thank you! Tempshill (talk) 05:50, 29 May 2009 (UTC)[reply]

May 29

Right Align a Button

Hello. How do I right align a button in Java? I do not want it to occupy the whole right edge. Any leads are greatly appreciated. --Mayfare (talk) 02:00, 29 May 2009 (UTC)[reply]

Your question has two possible meanings: Do you want to align the button itself to the right side of the container it is in? Do you want to align the contents of the button to the right side of the button? -- kainaw ™ 12:13, 29 May 2009 (UTC)[reply]

Here is a tutorial on this topic, assuming you're talking about Swing. --Sean 13:40, 29 May 2009 (UTC)[reply]

ISP keeping record of MSN Messenger Conversations

Does your ISP keep a history/record of your MSN Messenger conversations? Hence, if both parties choose for their Messenger to not keep a history of their conversations, is there anyway that their conversation can be retrieved? Acceptable (talk) 02:01, 29 May 2009 (UTC)[reply]

I think it's highly unlikely because of privacy issues, but you'd have to check their terms and conditions to be sure they don't have monitoring clause - The only exception would be if one of you is accessing the Internet via their work/VPN because it's quite possible they might have monitor clauses. If anything it'll be another node somewhere between yourself and the other person who's monitoring the communication but that's very unlikely - or at least it should be unlikely. I'd say the most likely problem would be someone recording their side (either intentionally or by accident) and that copy getting out. If you're really that worried about it then you may both wish to install something like SimpLite which will encrypt your conversation, it won't stop any local logging, but it'll stop any unauthorised snooping - Both sides have to have it running though! Hope this helps! ZX81 ^talk 02:36, 29 May 2009 (UTC)[reply]

But it is rather trivial to capture instant messages though. I have a plugin on my pfSense box that does exactly that. --antilived^{T | C | G} 04:04, 29 May 2009 (UTC)[reply]

It looks like you live in a relatively free country. In more oppressive places like the EU the government may keep track of your communications. 121.72.205.147 (talk) 06:27, 31 May 2009 (UTC)[reply]

it dont create it...if u live in a place lik that then u no it...an they watch u with ur webcam even if its off... —Preceding unsigned comment added by Ntower34 (talk • contribs) 08:27, 31 May 2009 (UTC)[reply]

Image help - trying to upload to commons

I am trying to upload an image to the Commons but I'm having file extension problems. I don't have much experience with image editing programs. I downloaded an image (digitized newspaper page) to my computer. There's no problem with the original image which is a .png. Needing to crop it, I tried various programs (paint, Wimdows image and fax viewer) but they don't have cropping tools. I then found PhotoPlus 6 on my computer and was able to crop it fine. However, when I saved it, it became a an .ssp image, whatever that is, which the commons doesn't recognize. The only other option the PhotoPlus program gives you in "save as type" is "all files (*.*). I tried that but that too the commons upload form refused. I then tried to open it with paint and windows image viewer to see if I could then resave it as a proper extension using them, but they wouldn't open it either. Long and short of it, I'm stuck. Any way to use this version of the image--to convert it? And if not, can anyone suggest a free image program I can download to crop again that will allow me to save the cropped image in a supported file extension format?--Fuhghettaboutit (talk) 03:58, 29 May 2009 (UTC)[reply]

Just use a proper image-editing software, like Paint.NET or GIMP. --antilived^{T | C | G} 04:05, 29 May 2009 (UTC)[reply]

Downloaded Paint.NET. Worked like a charm—cropped, saved, uploaded (here). Thanks.--Fuhghettaboutit (talk) 05:35, 29 May 2009 (UTC)[reply]

Java platforms

I am studyin java language on my own using a proffessional referance guide. It's actually a Java2 platform. My current PC is a windows XP so My commands and stuff and even the applications I write dont work! I even tried using source files from the net but my commands seem not to yield anything! Pls help me.... —Preceding unsigned comment added by 208.49.241.227 (talk) 08:01, 29 May 2009 (UTC)[reply]

You should tell what you have done so far. It's hard to help otherwise. --194.197.235.28 (talk) 08:45, 29 May 2009 (UTC)[reply]

Are you sure you have the Java Development Kit (compiler) installed, and is the directory on your path? Nimur (talk) 14:41, 29 May 2009 (UTC)[reply]

Need Software: Unique color counter

I'm looking for a software which can count the number of an unique color in a picture. For example, I want to know how many numbers of the color (20,167,99) in a picture. --百楽兎 11:15, 29 May 2009 (UTC)[reply]

The following (Python program) does that. It needs Python Imaging Library.

image_name = 'test.jpg'            # change as appropriate
desired_colour = (20,167,99)       # change as appropriate

import Image  # python imaging library

count=0
i = Image.open(image_name)
width,height = i.size
read_pixel_access = i.load() 

for x in range (0, width):
    for y in range(0, height):
        if read_pixel_access[x,y]==desired_colour:
            count += 1

print 'found', count, 'copies'

Let me know if you want it to find a unique colour, rather than just counting a specific one. 87.114.167.162 (talk) 11:55, 29 May 2009 (UTC)[reply]

Thank you but I can not run Python in this environment. Could you compile it to be an executable program for me? And actually, I have to count many colors' number, not only (20,167,99).--百楽兎 12:05, 29 May 2009 (UTC)[reply]

I have written you a Win32 executable. Please download [3]. If you use Linux, it will run under Wine. --Andreas Rejbrand (talk) 12:28, 29 May 2009 (UTC)[reply]

With all due respect to Andreas Rejbrand, the original poster should be aware that there is a security risk in running any untrusted executable on their computer. I'll bring this up on the RefDesk Talk Page in more detail. Nimur (talk) 16:25, 29 May 2009 (UTC)[reply]

I guess you mean a Windows executable - I'm afraid I don't have a Windows machine to hand to do that (but maybe someone who does will do a py2exe for you). Anyway, here's the code to count all the colours in the image and display them in descending popularity (most first) sort order:

image_name = 'test.jpg'

import Image  # python imaging library
d = {}
i = Image.open(image_name)
width,height = i.size
read_pixel_access = i.load() 

for x in range (0, width):
    for y in range(0, height):
        (r,g,b) = read_pixel_access[x,y]
        if d.has_key((r,g,b)):
            d[(r,g,b)] += 1
        else:
            d[(r,g,b)] = 1

for col,count in sorted(d.items(), key=lambda (k,v): (v,k), reverse=True):
    print col, '-->', count

Hope this helps. 87.114.167.162 (talk) 12:30, 29 May 2009 (UTC)[reply]

Yes, it is really helpful! Thanks very much to 87.114.167.162 and Andreas Rejbrand!
And by the way, (please see this screenshot first) what is the purpose of the question area? It's always blank.--百楽兎 14:00, 29 May 2009 (UTC)[reply]

I intended to show the bitmap there, but obviously I forgot to add the code for it! --Andreas Rejbrand (talk) 14:05, 29 May 2009 (UTC)[reply]

It's alright and not a problem, although showing the bitmap may be convenient to pick a color. And thank you for so kindly help again.--百楽兎 22:48, 29 May 2009 (UTC)[reply]

Computing history: personal computers today vs. supercomputers in the past

How far do you have to go back in time before a typical personal computer today (say one that retails for $1000) would qualify as supercomputer (perhaps just an entry-level one)? —Preceding unsigned comment added by 98.114.98.146 (talk) 12:19, 29 May 2009 (UTC)[reply]

The first machine in Supercomputer#Timeline_of_supercomputers is listed as doing 1 operation per second, which is vastly slower than even the first PC. If you don't want to count the Zuse V1 as a supercomputer, you'll have to come up with your own definition of the term, and then perhaps we could help answer the question in that context. --Sean 13:53, 29 May 2009 (UTC)[reply]

Then perhaps a better question would be...What is the 'newest' supercomputer that is slower than today's average computer (say retail $1,000)? (that's how I had read the above question anyways) 194.221.133.226 (talk) 13:58, 29 May 2009 (UTC)[reply]

This (http://setiathome.berkeley.edu/forum_thread.php?id=42332) discussion may be of interest to you. 194.221.133.226 (talk) 14:02, 29 May 2009 (UTC)[reply]

A lot of "super-computers" were optimized for a specific software setup and preferred program(s), before the ideology of general purpose computing really took off, driven by highly customizable software written in high-level programming languages. Comparing a modern machine to some of the early machines, which might have had special instructions for particular application domains, is not a fair comparison. Even if you count things like FLOPs and memory size, there are some bizarre architectures which don't fit well into the modern set of benchmarks. Nimur (talk) 14:46, 29 May 2009 (UTC)[reply]

To summarise - the late 1980's.77.86.10.194 (talk) 16:25, 29 May 2009 (UTC)[reply]

I agree. A modern PC is probably roughly the power of a Cray-2. Bubba73 (talk), 06:39, 2 June 2009 (UTC)[reply]

Business simulation games

I'm looking to buy some simulation games for my uncle. He's usually into some heavy duty stuff like Capitalism Plus. I checked out the articles for that game and Business simulation games but can't figure out which one would be good and not some silly approximation of a simulation game. Can I please get some suggestions for some relatively new business simulation/simulation games that could run on his Windows XP system? —Preceding unsigned comment added by 59.95.223.163 (talk) 14:28, 29 May 2009 (UTC)[reply]

I don't remember the name, but there was an old shipping business simulator that I rather liked. You ran a shipping company and had to move stuff around the world by boat. Your goal was to make profit, buy more boats, maintain those you have, get more contracts to ship stuff, etc... -- kainaw ™ 15:01, 29 May 2009 (UTC)[reply]

That sounds a bit like Transport Tycoon, although it does ships, trains, and road transport. 87.114.167.162 (talk) 16:53, 29 May 2009 (UTC)[reply]

Ports of Call, perhaps? Surprisingly, we don't seem to have an article on this enduring classic, but you can still find it. -- Captain Disdain (talk) 00:08, 30 May 2009 (UTC)[reply]

Monopoly Tycoon was quite good too. It's not exactly new but I remember running it on XP. --antilived^{T | C | G} 02:55, 30 May 2009 (UTC)[reply]

Microsoft Office Outlook Connector - will it overfill my computer?

One of the bad things about web-based email, such as Hotmail, is that it is very laboreous to save copies of emails to one's hard drive. I am considering using Microsoft Office Outlook Connector with my Hotmail account, with the intention of downloading the emails via Outlook to my hard drive. I have several hundred, perhaps thousands, of Hotmail emails. If I use it, will my old computer be swamped by the thing trying to download gigabytes of stuff all at once? 84.13.52.104 (talk) 16:01, 29 May 2009 (UTC)[reply]

I doubt it, its unlikely to be in the gigabytes, I have around 5000 emails on my gmail account and its about 300mb.--Jac16888 ^Talk 16:05, 29 May 2009 (UTC)[reply]

Actually, Windows Live Hotmail now supports POP3 access, so you can use any email client, not just Outlook. --grawity 16:14, 30 May 2009 (UTC)[reply]

Free text file / note organizer

Anyone know of any free programs which are similar to AlfaPad? Thanks —Preceding unsigned comment added by 82.44.54.169 (talk) 17:23, 29 May 2009 (UTC)[reply]

It appears to be a very simple application, that every (moderately talented) programmer could make in a few hours (a bit more if you need to create your own "Rich Edit" styled editing component)... --Andreas Rejbrand (talk) 17:28, 29 May 2009 (UTC)[reply]

Treepad has a free version. -- kainaw ™ 17:31, 29 May 2009 (UTC)[reply]

Unfortunately I'm not a moderately talented programmer or anywhere near. Thank you Kainaw, I'll check that out —Preceding unsigned comment added by 82.44.54.169 (talk) 18:17, 29 May 2009 (UTC)[reply]

MSIE7 and Vista

I use MSIE7 in vista. My home page is D:\_www\INDEX.HTM on my hard disk. I use that as a sort of homebuilt favourites page. Any time I link to the outside world from that page or any time I click "Home" from an outside page MSIE/Vista insists on opening yet another tab in a different window. Is there anyway to make this work like it used to in XP where a click opens it in the current window/tab and a right click allows selection of a new tab or a new window? If so HOW! -- SGBailey (talk) 18:08, 29 May 2009 (UTC)[reply]

In Internet Options -> Security you'd need to make sure that "protected mode" is the same for the Internet zone and local Intranet (possibly Trusted sites too). You could disable Vista's User Account Control (not recommend), but the easiest thing would be to just tick all 3 as "Protected Mode = On" unless you have reasons not to. Otherwise you could upgrade to IE8 which works differently and doesn't mind opening different security zones in tabs and doesn't require a new window. Hope this helps! ZX81 ^talk 18:16, 29 May 2009 (UTC)[reply]

Thanks. I'll try one or other of those suggestions. -- SGBailey (talk) 16:53, 30 May 2009 (UTC)[reply]

I'm going to go ahead and be obnoxious here and suggest checking out Firefox or Opera browser, or at least upgrading to Internet Explorer 8. I'm fairly sure it even appears on Windows update and if you don't have it that means your PC might be behind on its patches. Gunrun (talk) 09:23, 2 June 2009 (UTC)[reply]

Interwiki bots

How do they match article titles in different languages? --PirateSmackK^Arrrr! 18:31, 29 May 2009 (UTC)[reply]

They probably use that list of interwiki links on the side of every page. At the bottom of the navigation area. [flaming lawyer] 19:09, 29 May 2009 (UTC)[reply]

I mean before there are any interwiki links on the side of a page. The interwiki bots that add those interwiki links in the first place. PirateSmackK^Arrrr! 19:21, 29 May 2009 (UTC)[reply]

I'd guess they use some Google Translate-like translator to determine which names would be equivalent in different languages. But I haven't programmed any interwiki bots recently, so I'm not really sure :/ [flaming lawyer] 23:17, 29 May 2009 (UTC)[reply]

I thought they simply added links that were in other languages. For example: Example on en.wiki may have an interwiki to fr:Example, but not de:Example. However, fr:Example does link to de:Example. The bot finds this, and adds de:Example to the Example page here. That's just speculation, though—I don't know if that's actually how it's done. Dendodge _T\^C 23:23, 29 May 2009 (UTC)[reply]

These bots may also be under human control, and simply accelerate the process by performing the repetitive parts. A human translator might provide the initial input, and let the bot do the rest. If you have a specific bot in mind, you can definitely write to its owner or leave a message at its talk page. Some bot owners will gladly discuss implementation details. Nimur (talk) 18:55, 30 May 2009 (UTC)[reply]

Bypass root password and /etc/fstab

Resolved

What is the best way to bypass the root password for a program (on Linux)? I want to do that for some software I am working on (RUNZ). I need to do it because runz requires the "mount" command. What is the best option?

use /etc/fstab - is it possible to make some whitelist on /etc/fstab to allow runz to mount any filetype at /tmp/random_name ?
How about using the setuid thing? Is it worth it to create a binary that would run as root without password? And if the binary is just a launcher for the script, would it be compatible with all (at least recent) linux distros? (my guess is: no)
How about using /etc/sudoers to whitelist runz? is that a good idea?

PS: FUSE does not seems to be a good option since it can't mount all filetypes supported by "mount".

Thanks __ Hacktolive (talk) 19:19, 29 May 2009 (UTC)[reply]

I'd suggest using 'sudo' to do this, but I'm not certain I understand what you'd want to do, even after reading the web page for "RUNZ". The danger is that someone could use it to mount something on /etc or /lib, which would be bad. Also, what are you trying to mount using 'mount'? I know you've rejected using FUSE already, but why wouldn't a plugin for FUSE be appropriate? -- JSBillings 19:37, 29 May 2009 (UTC)[reply]

Also, if a user can mount arbitrary filesystems, they can mount one that contains a setuid binary of their choice (such as a setuid shell). Then they can do anything. Tread carefully. -- Coneslayer (talk) 19:40, 29 May 2009 (UTC)[reply]

Thanks for the answers. I do not want to allow "mount" to run as root without the password prompt, but only the runz framework would run as root (without password question). I have taken several security measures (only mount files to /tmp and mount all files with -nosuid -nodev -r -- full security measures here) to ensure this is safe, so I think the security problems mentioned above do not apply. Regarding FUSE, I just can't find a UDF module for it. I have also considered mountlo, but it does not work very well... Hacktolive (talk) 20:07, 29 May 2009 (UTC)[reply]

(Sorry for being a miseryguts) I don't really understand what value-add you're getting from your mount-the-iso scheme, as opposed to a simple shar (or a self-extracting archive)? 87.114.167.162 (talk) 21:18, 29 May 2009 (UTC)[reply]

No problem, I am happy with (constructive) criticism. I also noted the Linux and Ubuntu comunities do not seem very interested in my project, but I do it mainly because:

Running files should be easy! No need to mark as executable etc... (self-extracting files don't really work out-of-the-box for noobs)
Being an ISO, it has many advantages, like being faster to open the files, reducing wear and tear on the HDD, etc... I think the design is just more simple and "elegant".

I really think this is a good idea, and I plan to include it in SP1 for Super OS 9.04... like I said, any opinions/criticism are wellcome __ Hacktolive (talk) 21:53, 29 May 2009 (UTC)[reply]

You can ask hal to mount things. Ask it over dbus. It's not really my area of expertise, so others might need to fill in the details, but could be something to think about? --h2g2bob (talk) 00:07, 30 May 2009 (UTC)[reply]

Thanks for the tip, however, I have no idea how to do that... Hacktolive (talk) 02:32, 30 May 2009 (UTC)[reply]

Does fuseiso meet your needs? Do you intend to use this loopback-mounted volume to permanently run apps, or just as a means to store installable packages? It's not clear from the web site. -- JSBillings 02:15, 30 May 2009 (UTC)[reply]

The problem is that fuseiso does not support UDF... and I really want to have support for large volumes... I am not sure what you mean... this method is just to run apps from the mounted file, the mounted file in unmounted once the user quits the app. Hacktolive (talk) 02:32, 30 May 2009 (UTC)[reply]

ISO 9660 supports volume sizes up to several terabytes at least. It's unlikely that you'd need UDF. -- BenRG (talk) 18:05, 30 May 2009 (UTC)[reply]

It might... but not without "hacks". Everytime I tried to burn big files (4GB+) to DVDs I always had problems with the ISO format, I had to use UDF. Anyway, I ended up using mountlo, and I know the proper solution for this might be a setuid wrapper. Thanks. ___Hacktolive (talk) 23:59, 4 June 2009 (UTC)[reply]

May 30

How do you make a group on Facebook?

Question as title. Does anyone know? --KageTora - (영호 (影虎)) (talk) 01:23, 30 May 2009 (UTC)[reply]

http://www.facebook.com/groups/create.php — Matt Eason ^{(Talk  Contribs)} 01:39, 30 May 2009 (UTC)[reply]

Aha! Thanks! --KageTora - (영호 (影虎)) (talk) 01:50, 30 May 2009 (UTC)[reply]

MIDI rendering to a multi-track format

Do any programs exist that can render a MIDI mockup into waveform while keeping each MIDI instrument separate in the output (e.g. if it is uncertain for which instruments real recordings will be available)? Neon Merlin 05:35, 30 May 2009 (UTC)[reply]

I use TiMidity (free, OpenSourced) - it has a bazillion replay options - you can certainly disable playback channel-by-channel...I think it can probably do track-by-track too, but I've never tried that. SteveBaker (talk) 20:12, 30 May 2009 (UTC)[reply]

My PC frezes or stops at windows loading screen

Hi friends!, My PC config is 256MB RAM,Zebronics(low-cost,local) motherboard with 865 intel chipset. Samsung 80GB Hardisk. I've been using the PC for longer time. recently I had this problem (that the pc freezes at the loading screen).So I thought of re-installing windows XP with a bootable cd since there was no use in booting using safe-mode or best last known configuration modes. The initial process of copying and partitioning my hardisk was ok. After formatting C drive and copying system files,the PC restarted and before the installation screen,the windows loading logo screen appeared and it freezed immediately when the loading bar scrolled to the end. I immediately checked for RAM issue and then replaced with new one, and still the same problem persisted. Later I Checked my Hardisk by installing XP with another pc,and to my surprise that too was working great...And another problem is BIOS,I guess the battery is OFF,since it dislayed checksum error each time i switch off,and the settings will be restored to default. Could this mean to make any problem?..My feel is motherboard which is the issue...But I',m not sure...So if you guys have any idea,please help me make decision and solution..thank you guys —Preceding unsigned comment added by Balan rajan (talk • contribs) 06:12, 30 May 2009 (UTC)[reply]

I am not an expert, but when my computer froze at start up and would only start in safe mode, I eventually found it was cured by turning the video driver off. It may have been a defective video card. You can get the computer to show you what it is loading during start up - sorry forgiotten how to do this. The last thing mine showed loading was mump.sys, but a lot of busy stuff starts then and it was very difficult to find out what the problem was. If you have a bad bios checksum then perhaps you should remove the CMOS battery for several minutes, and replace it with a new one, in an attempt to refersh the bios, but I'm already out of my depth here. 78.147.249.77 (talk) 17:19, 30 May 2009 (UTC)[reply]

Mysterious new drive

I rebooted my PC after it had frozen up. Vista then told me it had successfully installed the driver software for my floppy disc drive. And when I look at my list of drives the floppy disc is there as drive A. The problem is I do not have a floppy disc drive. Never have had one. And I've not added any new hardware of any kind recently. So where has this mysterious new drive come from. How do I remove it? 58.169.214.60 (talk) 07:12, 30 May 2009 (UTC)[reply]

Possibly your motherboard has an internal floppy disc controller, and Vista (being the helpful soul that it is) figured you'd want a driver for it, because otherwise you couldn't use it. Can't really fault an OS for assuming you'd want drivers installed for something in your PC though. I think I also have an A drive showing even though I have no floppy drive plugged in. Gunrun (talk) 09:21, 2 June 2009 (UTC)[reply]

Firefox's salting folder

Where is my Firefox's salting folder? Has anyone seen it? I found no *.slt in my system. I have only the default installation of Firefox on Ubuntu.--Mr.K. (talk) 09:46, 30 May 2009 (UTC)[reply]

The .slt extension isn't used anymore. You can find your profile directory under:

/home/username/.mozilla/firefox/xxxxxxxx.Profile Name/

chocolateboy (talk) 05:08, 31 May 2009 (UTC)[reply]

"�" characters

In some Wikipedia pages with unusual characters, these characters are displayed as "�". How can I view them? I tried Internet Explorer and Firefox and they both couldn't view them. 95.84.64.174 (talk) 09:52, 30 May 2009 (UTC)[reply]

This is the character shown when a Unicode character cannot be displayed. What operating system do you use? If you use Windows XP or Vista, or some (modern) Linux distribution, or Mac OS X, you should have full Unicode support in all (common) browsers. If you use an old operating system, such as Windows 9x, you probably do not have Unicode support (though I believe you can download something called "Microsoft Layer for Unicode" to add it). --Andreas Rejbrand (talk) 09:57, 30 May 2009 (UTC)[reply]

But now I realize that you probably do have Unicode support, for the character � itself is not available in primitive charsets such as ASCII, ANSI, and so on. Have you tried to right-click on the page, choose "Encoding" and then "UTF-8" or "Unicode"? --Andreas Rejbrand (talk) 09:59, 30 May 2009 (UTC)[reply]

I think that all of the major browsers had full Unicode support on Win9x (Internet Explorer definitely—it even had a Japanese IME for English Windows). Microsoft Layer for Unicode is for applications that were designed for it (and require it). It doesn't add Unicode support to other applications. Manually setting the encoding is only necessary when the web page doesn't specify it or specifies it incorrectly, which should never happen with Wikipedia. -- BenRG (talk) 17:12, 30 May 2009 (UTC)[reply]

I'm using Windows Vista. I checked, encoding is set on UTF-8. One example page is Dash#Swung_dash. I see "The swung dash (� or ~) resembles a ...". 95.84.64.174 (talk) 11:07, 30 May 2009 (UTC)[reply]

Install a Unicode font that supports this character. -- 200.234.107.35 (talk) 11:25, 30 May 2009 (UTC)[reply]

On almost all Windows Vista systems, there are good Unicode fonts from the beginning. Two of the most common are Arial Unicode MS and Lucida Sans Unicode. The DejaVu family of fonts (serif, sans-serif, monospaced etc.) are free, high-quality Unicode fonts. --Andreas Rejbrand (talk) 13:20, 30 May 2009 (UTC)[reply]

And how can I view internet pages using those fonts? I tried copying the troublesome text into Microsoft Word and changing the font to Arial Unicode MS, but it still didn't work. 95.84.64.174 (talk) 14:01, 30 May 2009 (UTC)[reply]

Usually you don't have to tell the browsers what fonts to use. They should select them automatically. If the sample text didn't appear even after your test with MS Word, it means that Arial Unicode MS doesn't have that character. Install one of the free fonts Andreas mentioned to check if they support your symbols (my system doesn't show them either... they must be very rare :p ) . -- 189.69.146.130 (talk) 15:49, 30 May 2009 (UTC)[reply]

If you're talking about the symbols in this thread, that's because they're all U+FFFD, the Unicode replacement character. What that looks like will depend on your browser. On mine it looks like a black diamond with a question mark in it. The swung dash at Dash#Swung_dash displays on my machine but the quoted copy here doesn't. Apparently it was destroyed by the OP's browser or by the copy-paste process, but I don't know why. -- BenRG (talk) 17:12, 30 May 2009 (UTC)[reply]

I replaced the text here with the replacement character myself to explain my problem. But when I tried to copy-paste the text from that article into Word, they also showed as the replacement character. I'll try installing the DejaVu fonts and see what happens. 95.84.64.174 (talk) 18:41, 30 May 2009 (UTC)[reply]

FWIW, on my Vista system, the character is shown correctly in Google Chrome 2.0 and Firefox 3.07, but not in Internet Explorer 7 and Safari 4 beta. --Andreas Rejbrand (talk) 19:33, 30 May 2009 (UTC)[reply]

Copy-pasting the characters into MS Word and changing the font to one of the DejaVu family worked! I also upgraded Firefox to 3.0.9 and it worked there. Thank you for your help. But I still wonder if there is a way to view then in Internet Explorer. 95.84.64.174 (talk) 21:20, 30 May 2009 (UTC)[reply]

Have you tried Internet Explorer 8? --Andreas Rejbrand (talk) 19:23, 31 May 2009 (UTC)[reply]

Online "single page" feed reader

Is there any other online simple feed reader like Planetaki? It shows new posts from different sources as if they were a single a blog. I want a service similar to it with an option to assign categories or labels to subscriptions. -- 200.234.107.35 (talk) 11:20, 30 May 2009 (UTC)[reply]

Have you tried Google Reader? Rawling4851 15:25, 30 May 2009 (UTC)[reply]

Yes. I'm writing a list of simple alternatives for the readers of my blog, and it'd be nice to mention another Planetaki-like site, if it existed. :) -- 189.69.146.130 (talk) 15:41, 30 May 2009 (UTC)[reply]

Cafepress/Zazzle/Spreadshirt market share

Which one has the highest market share? Which has the most revenue? The most user-created designs? —Preceding unsigned comment added by Herzog (talk • contribs) 17:38, 30 May 2009 (UTC)[reply]

Giveaways and antitrust

I've posted a question to the Humanities desk asking whether Internet Explorer is the only free-of-charge product in history to be the center of an antitrust case. Responses there please. Thanks - Tempshill (talk) 18:19, 30 May 2009 (UTC)[reply]

May 31

Perl, MySQL, TEXT, HTML, DBI escape characters

I want to store several HTML segments (ISO-8859-1 or ASCII) in a TEXT field of a MySQL database using Perl.

How do I escape certain characters for MySQL?

How do I restore them? -- Toytoy (talk) 00:30, 31 May 2009 (UTC)[reply]

Have you looked at the DBI documentation? Check out quote(). -- JSBillings 21:13, 31 May 2009 (UTC)[reply]

The easiest way is to use placeholders, which will do the right thing for you, even if the parameter is NULL/undef:

$statement = $dbh->prepare("insert into mytable(html_field) values(?)");
$statement->execute("<some>html with quote's...");  # quotes it
$statement->execute(undef); # inserts NULL

--Sean 12:38, 1 June 2009 (UTC)[reply]

I Remember This Website

I remember going to this website that started out as a page full of mouse cursors. Moving your mouse would cause all of the cursors to move, and you had to find the right cursor and click a button before you could continue. It then took you to this page that contained a post-it note with the words "remember this name" on it and a text area below. Typing in your name would take you to this page that copied a news website (CNN.com, The New York Times, ect.) with parts of the news story replaced by the name you typed in. If anyone could direct me to this website, I would be much obliged.

Americanfreedom (talk) 04:48, 31 May 2009 (UTC)[reply]

No field of mice on these, but this site offers realistic stories realistic stories and this one clearly phoney ones, both with inserting the names of your choice.KoolerStill (talk) 13:41, 31 May 2009 (UTC)[reply]

Media players for GNU/Linux

Is there a modern (e.g. Banshee or Quod Libet) audio player on GNU/Linux for GNOME that supports DSP plugins? Two specific effects I'm looking for is a compressor (I hate songs with high dynamic range) and a stereo-to-5.1 converter (not essential though). Note: I don't want ReplayGain or anything like that... --wj32 ^t/c 06:23, 31 May 2009 (UTC)[reply]

This might help. If the audio player supports JACK then you can probably do it, but I have no idea how. --antilived^{T | C | G} 05:29, 1 June 2009 (UTC)[reply]

I have an annoying problem...

I have a problem. There's this thing where I get a red pop-up at the bottom-right corner of the screen about an Antivirus System Pro alert about a trojan. I blocked the attack, but after some time, it appears again. I blocked it again. But it appeared again and again and again. I tried to ignore it, but then a pop-up appeared in the center of the screen about the alert. How can I figure this problem out? —Preceding unsigned comment added by Sirdrink13309622 (talk • contribs) 14:31, 31 May 2009 (UTC)[reply]

A quick Google suggests Antivirus System Pro is malware. It is a program which pretends to be antivirus program, but is in fact scareware. Download a decent antivirus program like AVG, McAfee Antivirus or Symantec Antivirus. AVG is free (I think), the others may have free versions. These proper antivirus programs should remove it.

You might want to read information about keeping safe from malware from the BBC. Page 3 has suggestions about antivirus software. --h2g2bob (talk) 16:36, 31 May 2009 (UTC)[reply]

"Antivirus System Pro" is well known example of scareware. Your best bet to remove scareware is to go with Malwarebytes' Anti-Malware and SUPERAntiSpyware. Both should be installed, updated, and used immediately to remove Antivirus System Pro. Afterwards, a proper anti-virus like avast! or Avira AntiVir should be installed. Under no conditions should you sacrifice your personal or financial information to this scareware product. The product isn't blocking anything but fake threats to scare you into buying it. Even Google-searching for information on some scareware threats these days can be dangerous. Some of the results may be fake scareware-removal instruction sites that may distribute the scareware itself or another piece of scareware labeled as a "remover of <rogue threat name here>" or other malware. New rogue scanner sites with updated versions of scareware not yet detected by almost any anti-virus go online everyday. To help keep yourself safe while surfing the Web I highly recommend the Web of Trust add-on for Firefox and Internet Explorer. (Far superior to McAfee SiteAdvisor which I dumped a long time ago) Most importantly though, you, the user, is the most important part of online safety. Good luck.--Xp54321^{(Hello! • Contribs)} 17:59, 31 May 2009 (UTC)[reply]

Where did my disk space go?

I would like to find a program (free, preferably) that would make it easier for me to track down folders and files hogging space on my hard drive. What I'm picturing is something that looks a bit like the folders panel of Windows Explorer, but with percentages or raw numbers indicating how much memory each folder is taking up. Even better would be something that broke it down to sub-folders too. Maybe something like:

Pictures (4.5 GB)

Kids (2.1 GB)

Molly (1.5 GB)

Nieces (600 MB)

Vacations (2.4 GB)

Camping (2 GB)

Niagara Falls (400 MB)

Is there anything like that out there? I'm running XP SP 3. Matt Deres (talk) 14:56, 31 May 2009 (UTC)[reply]

I find SequoiaView works great for this. It represents things visually which makes it a lot easier to figure out what's going on. --98.217.14.211 (talk) 17:34, 31 May 2009 (UTC)[reply]

I think that WinDirStat is great. —Preceding unsigned comment added by Andreas Rejbrand (talk • contribs) 18:09, 31 May 2009 (UTC)[reply]

Both of the above are rubbish in my experience and didn't do for me what I think you're looking for, which is integration straight into Windows Explorer. I had EXACTLY the same issue as you and I can tell you what you need is FolderSize. It's free and I've been using it for over a year now and it works brilliantly. It allows you to add columns for "Folder Size" and a few others to your Windows Explorer "Details" view, and in fact can replace your usual "Size" column. It does exactly what it says on the tin. Install it, right-click on the column headings and add "Folder Size" as one of the columns. Job done. Zunaid 20:36, 31 May 2009 (UTC)[reply]

Yes, and yes. I use and love "Folder size". It has made my life better, and they are not paying me to say this! :) -GTBacchus^(talk) 20:40, 31 May 2009 (UTC)[reply]

Brief warning about folder size. It uses a background process to update the values continuously. That can sometimes slow down your system significantly. If you map network drives, it will venture off there as well, looking through all directories it can access, and start adding up. My work took twice the usual time for a week before I realized my computer was busy determining the folder sizes of everything publicly available on the company servers. /Coffeeshivers (talk) 20:49, 2 June 2009 (UTC)[reply]

My two cents: Treesize Free. Can give you a view pretty much exactly like your example. Rawling4851 00:02, 1 June 2009 (UTC)[reply]

Is it too much to tell the OP to get Ubuntu and use its Disk Usage Analyzer :p? --antilived^{T | C | G} 05:21, 1 June 2009 (UTC)[reply]

Oh, no, no! Well, you know, not if you don't mind proselytizing instead of giving useful advice. "Oh, you have a tummy ache? You know what works really well for that? Jesus." -- Captain Disdain (talk) 06:57, 1 June 2009 (UTC)[reply]

I'm not worried about that. I have Jesus in my trunk!Matt Deres (talk) 23:24, 2 June 2009 (UTC)[reply]

Thanks for the options, guys. I had tried SequiaView... I think (very similar to WinDirStat in looks). FolderSize sounds more like what I'm looking for. I'll give it a go, though I'll keep an eye out for system lag. I have an external I often plug-in that has a gazillion folders on it; hopefully the proggie has a way of skipping drives or something. Matt Deres (talk) 23:22, 2 June 2009 (UTC)[reply]

Computer Graphics

Prove that two successive reflection about any axis coordinate axis is equivalent to a single rotation about the coordinate origin

You might like to read Transformation matrix. 87.114.167.162 (talk) 16:58, 31 May 2009 (UTC)[reply]

And possibly do your own homework as well. -- Captain Disdain (talk) 17:26, 31 May 2009 (UTC)[reply]

Please do your own homework.

Welcome to the Wikipedia Reference Desk. Your question appears to be a homework question. I apologize if this is a misinterpretation, but it is our aim here not to do people's homework for them, but to merely aid them in doing it themselves. Letting someone else do your homework does not help you learn nearly as much as doing it yourself. Please attempt to solve the problem or answer the question yourself first. If you need help with a specific part of your homework, feel free to tell us where you are stuck and ask for help. If you need help grasping the concept of a problem, by all means let us know. SteveBaker (talk) 21:29, 31 May 2009 (UTC)[reply]

Also try asking for help on the maths desk - not here...77.86.10.194 (talk) 19:09, 1 June 2009 (UTC)[reply]

goto in structural languages

One thing that's always kept puzzling me about goto in structural languages is, what happens if the goto jumps between different structures? For example, consider these C examples:

for (i=0; i<10; i++) {
  printf("%d\n", i);
  if (i==5)
    goto label;
}
label: printf("Hello world!\n");

for (i=0; i<10; i++) {
  label: printf("%d\n", i);
 }
 goto label;

Is there any formal specification about what happens in these cases? There are many other structured languages implementing goto too. What is the case in them? JIP | Talk 19:22, 31 May 2009 (UTC)[reply]

(Answer for C++, should be mostly correct for C as well): When you jump out of a scope (such as a loop or a block), all objects declared in that scope are destroyed. You can not jump back into a scope if it bypasses an object declaration, with the exception of declarations of POD types without initializers. So

 for (int i=0; i<10; i++) {
  label: 0;
 }
 goto label; // ill-formed, jump bypasses declaration and initialization of i

On the other hand:

 int i;
 for (i=0; i<10; i++) {
  label: 0;
 }
 goto label; // OK, no declarations bypassed

And lastly

 {
 int i;
   label: 0;
 }
 goto label; // OK, passes declaration of a POD type w/o initialization.

The same rules apply in a switch as well. decltype (talk) 20:09, 31 May 2009 (UTC)[reply]

Needless to say, this sort of scope goto-ing is "bad form" and will lead to unmaintainable code, so use such coding style with discretion. Nimur (talk) 21:22, 31 May 2009 (UTC)[reply]

(ec) In truth - the goto statement should be firmly ignored in all modern languages. They are a major disruption to the legibility of code. Hence, you don't need to know what it does (unless you are a compiler writer) - because you aren't ever going to use one! There is absolutely no circumstance when a goto is either needed or desirable. The only reason so many languages retain it at all is in order to simplify the automatic translation of older, goto-laden programs that were written in non-structured languages (for example FORTRAN or BASIC). In those cases, the lack of structure in the original language means that these problematic cases do not in fact come up at all in practice. Hence the rules on the meaning for the ikky corner-cases generally follows whatever is the simplest thing to implement in the compiler rather than what makes most logical sense for programmers. The last time I saw a professional programmer use a goto was about 15 years ago - and when the rest of the team found out about it, he was mocked for weeks afterwards. Personally, I can say with authority that I've never felt the slightest desire to use a goto statement in a structured programming language - not since I was told by one of the lecturers at the university I attended that we would be awarded an automatic zero on any coursework turned in with a goto in it! That was in the mid-1970's - so if I can go 35 years without using one - so can you! SteveBaker (talk) 21:28, 31 May 2009 (UTC)[reply]

The last time I saw someone use a goto was about 3 years ago and yes he was mocked by with co-workers for weeks afterwords. BTW, Classic VB didn't have structured exception handling so if you wanted to gracefully handle all errors, you were pretty much forced to include an On Error Goto ErrHandler in every event handler and callback function in your application. If you wanted to keep track of your call stack, you had to code an On Error Goto ErrHandler in every single function in your application. A Quest For Knowledge (talk) 22:31, 31 May 2009 (UTC)[reply]

That's a pretty extreme viewpoint. It is true that in nearly all cases, goto should be avoided, but I wouldn't go so far as to say that it is always evil and should never be used by anyone ever. On the other hand, this "always-evil" attitude toward goto has become quite popular in the last 40 years. —Bkell (talk) 21:38, 31 May 2009 (UTC)[reply]

The only good examples I've seen of using goto is for cleanup (of allocated memory, etc) after errors. An example of use is in the Python-C API docs. --h2g2bob (talk) 22:09, 31 May 2009 (UTC)[reply]

The earliest structured programming languages were strictly single-entry-single-exit; the only way to return from a function was by running off the end, the only way to exit a loop was by reaching the end of the range, etc. So if you use break, continue or return (except as the last line of a function) then you're using something that the early structured programmers would have considered a harmful goto. In order to work around those limitations programmers would explicitly assign a large value to the loop variable or introduce a boolean variable named "done", and I think C's structure-violating exit statements are more readable than those techniques. C programmers sometimes do the same thing to compensate for deficiencies in C's control constructs, like the lack of multi-level break (as found in Perl, for example), and I tend to prefer goto in those cases also. But if your function has gotten that complicated you're almost certainly better off splitting it into several and solving the problem that way.

Probably the most important use of goto, though, is for machine-generated code. There are a lot of compilers that use C as a backend, and it's much easier to output labeled basic blocks and gotos than try to translate your high level control structures into C's. The resulting machine code is the same, since one of the first things a typical C compiler does is turn all control structures into gotos. -- BenRG (talk) 22:43, 31 May 2009 (UTC)[reply]

Indeed. There are 30,000+ projects written in C on sourceforge.net, and many more beyond. Unifying error cleanup with a "goto error_cleanup" is the closest thing they've got to proper exception handling, and it's silly for them not to use it. --Sean 12:59, 1 June 2009 (UTC)[reply]

Both of your examples (are horrible but) have well-defined semantics. In the first one, goto label behaves the same as break. In the second one, i is 10 upon exit from the loop; when you jump back in, it is still 10 and so 10 is printed, then it is incremented to 11 and the loop exits again since i<10 is false, then it jumps back in and 11 is printed, and so on. -- BenRG (talk) 22:43, 31 May 2009 (UTC)[reply]

Just about all primitive (read mid-20th century) uses of goto have been superseded by more advanced constructs. The if-then-else, for-while-until, case or switch statements, break, continue, and return statements, and more recently the try-throw-catch constructs all evolved from a need to more clearly codify execution flow that at one time was accomplished with goto's. In my opinion, the try-throw-catch construct eliminated the last need for the average programmer to use goto's. Prior to that goto-less code containing robust error handling often contained a combination of boolean flags and nested if statements that made the normal logic less readable. In some circles, use of the return statement is still considered bad form when used to exit the middle of a function. Now there still may be some cases where a goto is justified, such at to achieve a few percent performance gain in a light loop of a highly optimized library function, but the typical programmer has no need for this, relying instead on the efficiency of library functions written by others. -- Tcncv (talk) 00:32, 1 June 2009 (UTC)[reply]

I'd only consider goto for special applications, for example copying an algorithm out of Knuth using goto will often be more obvious and less error-prone than trying to beautify it. Also one might be using C as an assembly language and use macros with goto's in them for the higher level. They have their uses but should definitely be avoided in the primary level of programming. Dmcq (talk) 12:55, 1 June 2009 (UTC)[reply]

Use of 'return' in the middle of a function or 'break' in the middle of a loop (they are essentially the same thing from a structural sense) is 'iffy' - but there are cases when the clarity you get from doing it is more than worth the slight heartache each time you feel the need to do it. But:

bool myFunction ( Thing *thing )
{
  bool OK = true ;

  if ( thing != NULL )
  {
     if ( thing -> widget != NULL )
     {
       if ( thing -> widget -> otherWidget != NULL )
       {
          body of function ;
       }
       else
       {
         fprintf(stderr,"otherWidget is FUBAR\n" ) ;
         OK = false ;
       }
     }
     else
     {
       fprintf(stderr,"widget is FUBAR\n" ) ;
       OK = false ;
     }
  }
  else
  {
    fprintf(stderr,"thing is FUBAR\n" ) ;
    OK = false ;
  }

  return OK ;
}

...is incredibly painful because when you're trying to read the code, your brain is full of these buzzing little semi-conscious doubts about whether the error conditions will ever be properly resolved in the end.

It's so much nicer to get them out of the way early:

bool myFunction ( Thing *thing )
{
  if ( thing == NULL )
  {
    fprintf(stderr,"thing is FUBAR\n" ) ;
    return false ;
  }

  if ( thing -> widget == NULL )
  {
    fprintf(stderr,"widget is FUBAR\n" ) ;
    return false ;
  }

  if ( thing -> widget -> otherWidget != NULL )
  {
    fprintf(stderr,"otherWidget is FUBAR\n" ) ;
    return false ;
  }

  body of function ;
  return true ;
}

...that way you can be comfortably sure that all of the nasty things have been taken care of and go on to read the main part of the function with a clear head...and much less indentation!

But it's certainly possible to misuse 'return', 'break' and (especially) 'continue' in ways that make them almost as bad as a 'goto'. The biggest problem with a 'goto' is that when you're reading through some code and you trip over a 'label:' - you have absolutely no clue how the code gets there. But with break, return and continue, the only way to arrive at a close curly bracket is from within the brackets - or from the control statement at the top of the block. That makes it much simpler to reason about what code is doing. In most code, a block fits in a screen-full so it's easy to see what's going on as you scroll downwards through the source code reading as you go. But with a 'goto' you may not yet have seen the code that gets you to where you are reading...reasoning about what could possibly happen now requires you to have knowledge of all of the code in the scope that a goto could possibly have sent you to. Worse still, even when you find a goto that's aimed at the label you're reading, you don't know whether it's the only one or not. There could potentially be hundreds of places in the code that could get you to the code you're reading and you can't easily tell whether all of them adequately satisfy it's preconditions. This is definitely not good for debugging!

SteveBaker (talk) 21:29, 1 June 2009 (UTC)[reply]

Spreadsheet help

I have a workbook in excel 2000. There are 29 columns (A-AC) and many many rows. I want to combine column A with every other column in different workbooks. That is, I want to put comlumn A in the new workbook column A and column B in the new workbook column B. The next workbook will have column A in new A again and column C in new B, and so on. Is there a quick way of doing this without cutting and pasting? —Preceding unsigned comment added by 90.216.148.237 (talk) 19:54, 31 May 2009 (UTC)[reply]

I don't know much Excel (I use OOo), so workbook and worksheet are alien terms to me. Unless I'm mistaken, a workbook is the excel file (the .xls file). So you could copy your excel file (or save the excel file with a different name) and have 2 identical workbooks. Then just delete column B: right-click on the column header at the top of column B, and select delete. --h2g2bob (talk) 22:16, 31 May 2009 (UTC)[reply]

If you want to do this just to print the sheets separately, there are easier ways: you can go to "page setup", choose column A to be on every page you print (I think it is called "repeat column across pages" or something), and then insert manual page breaks between all the other columns. If you want to actually split the workbooks I think the easiest way would be some simple VBA code - if you have scripting experience, you can hit the "macro record" button, do some tries of what you want, and then look at and edit the code. There are also other ways, look into the OFFSET and VLOOKUP/HLOOKUP formulas, for example, and note that you can reference cells from one workbook to another. Jørgen (talk) 23:28, 31 May 2009 (UTC)[reply]

You can use Excel macros (Visual Basic for Applications). I used Tools > Macros > Record New Macro to record the steps needed to create the first two sheets using create sheet followed by a couple of copy & paste operations. After stopping the recording, I took a look at the resulting commands in the Visual Basic Editor. With a little bit of VBA programming, and replacing sheet and column names with numbers ("A:A" is column 1, "B:B" is column 2, etc) I came up with the following macro.

Sub DistributeColumns()
'
' Macro to copy columns A-AC from sheet 1 to additional sheets each containing two
' columns each: (A,B), (A,C), (A,D),... (A,AB, (A,AC).
'
    ' Add new sheets
    Sheets.Add After:=Sheets(1), Count:=28  ' Add sheets 2-29 (28 new sheets)
    
    ' Repeat for columns 2-29 (B - AC)
    For I = 2 To 29
        ' Copy and paste from sheet 1 column 1(A) to sheet <I> column 1(A)
        Sheets(1).Select
        Columns(1).Select
        Selection.Copy
        Sheets(I).Select
        Columns(1).Select
        ActiveSheet.Paste
        
        ' Copy and paste from sheet 1 column <I> to of sheet <I> column 2(B)
        Sheets(1).Select
        Columns(I).Select
        Application.CutCopyMode = False
        Selection.Copy
        Sheets(I).Select
        Columns(2).Select
        ActiveSheet.Paste
    Next i
End Sub

To use,

open the Visual Basic Editor within Excel (Tools > Macro > Visual Basic Editor).
Right Click VBAProject and select Add > Module.
Copy and paste the above code into the module window.
Click the run button (green arrow) at the top of the screen.

Unfortunately, I am running Excel 2007 on one machine and Excel 97 on another, so I cannot guarantee that the above will work for Excel 2000. (I'd give it a better than even chance though.) If you have problems, you can generate your own macro using the steps I created above and perhaps adapt the commands to the above script. Similar techniques can be used to automate many repetitive tasks in Excel and other macro enabled applications. Hope this helps. -- Tcncv (talk) 23:53, 31 May 2009 (UTC)[reply]

Why does reading scratched CDs lock up the PC?

Ever inserted a scratched CD or flaky floppy into a PC and tried accessing it? Why does the entire PC (rather than say just Windows Explorer or whatever program you're using) become unresponsive and/or extremely slow? I was copying files off a scratched CD today and could hardly operate any programs during the operation. Note I wasn't using Windows Explorer's copy but instead Total Commander. Right-clicking or double-clicking took an absolute age to respond. It is not a case of CPU usage (as confirmed by Task Manager). Also, why does reading a wonky CD cause the program to lock up anyway? Even hitting the cancel button on the copy operation took ages to register. Redrawing operations (mini- or maximizing, dragging windows around, clicking "show desktop") also took an age.

Is this just a Windows thing or is it standard behaviour that I/O operations cause everything else to lock up? And either way (either answer), why is that the case? Thanks. Zunaid 20:59, 31 May 2009 (UTC)[reply]

Well, a severely damaged CD or floppy will probably cause the device driver to perform multiple 'retries' to see if it can get the data that way. It may retract the drive heads all the way back to track zero of the drive - and perhaps even tell it to re-initialise it's firmware - all of which is pretty time-consuming - but necessary if you're to stand the best chance of getting the data off of the media. I don't know about Windows - but certainly under Linux, this wouldn't cause a total OS lockup. The retrying would be threaded just like other OS operations. However, there are different ways to handle it - and I suppose the Windows way might be somehow crappier. I doubt that it matters much which program you use - the retry should be hidden down at the device-driver layer. SteveBaker (talk) 21:10, 31 May 2009 (UTC)[reply]

Windows normally uses a high level API for accessing the CD, but in the event of crummy reads, it will switch to a low level ATAPI "raw read" utility. This is usually done when DMA fails (and therefore, is not hardware-accelerated and ties up the CPU). Why this CPU usage is not threaded is probably a "feature/bug" of the system. See this Windows Hardware Developer article on DMA for ATAPI devices if you want some more details - apparently six failures is the threshold for switching to PIO mode. Nimur (talk) 21:15, 31 May 2009 (UTC)[reply]

I've been troubled by this issue many times. It could be that CD-ROMs produce excessive interrupt requests, in which case they hog your CPU with IRQs asking for attention. I've seen this when another piece of hardware like a network card fails and hogs the CPU. But I think it's more likely that Windows Explorer simply has to update its list of disks every time a CD-ROM is inserted or accessed. Contrast this with when you, say, print a document, in which case its the print spooler that has to wait for the printer. If the spooler locks up, you don't notice, because you don't really interact with it. I've actually seen bad CD-ROM drives cause a computer to stop booting entirely.--76.120.121.128 (talk) 21:17, 31 May 2009 (UTC)[reply]

pirated apps download

Before I got my iPod Touch, I was playing around with one of my friends'. It was jailbroken. He had something on there (don't know if it was an app or just a hack or what) that, whenever he wanted a non-free App Store app, would take him to a list of pirating sites that hosted the particular app. I don't know what it's called, but I know it exists. Anybody have any idea what it's called? Thanks, [flaming lawyer] 21:56, 31 May 2009 (UTC)[reply]

It's unlikely the Reference Desk is going to help you out here. Try a search engine, I guess. Tempshill (talk) 23:48, 31 May 2009 (UTC)[reply]

I'm finding it hard not to think of the Apple advert: "You want to steal other people's hard work and pay nothing for it? We've got an App for that!". SteveBaker (talk) 21:03, 1 June 2009 (UTC)[reply]

June 1

Partition shift

Dear Wikipedians:

My favorite Slackware Linux is installed in the partition /dev/sda7. Recently I have split a partition that came before /dev/sda7 into two, hence pushing /dev/sda7 into /dev/sda8. I have remade a LILO bootdisk to bootup /dev/sda8, however, I find that when I try to boot the computer still looks for the root partition on /dev/sda7, which is now an NTFS partition.

I am wondering if there's anyway of getting /dev/sda8 to boot properly.

Thanks.

70.31.158.159 (talk) 01:17, 1 June 2009 (UTC)[reply]

Well, there's two steps to changing the "root" partition that lilo looks for. First, you'll need to edit your 'lilo.conf' file, which is probably in /etc. If it's on the bootdisk, I'm not sure where it would be. Find the entry for Slackware, and make sure to change the line that says "root=/dev/sda7" to sda8. Once you're done, save the file. If you're running this from a bootdisk, change to the superuser if you aren't already, and run "lilo". That's the second step, and it actually applies the changes. I could be wrong on some of the details, it's been a while since I used a dedicated LILO bootdisk. Just let us know if that doesn't help. Indeterminate (talk) 02:12, 3 June 2009 (UTC)[reply]

/dev/sda16 in Linux

Dear Wikipedians:

I ran into a most unexpected problem: My Linux box is refusing to recognizing partitions above /dev/sda15! (I use a SATA drive)

I googled the problem and it was suggested that /dev/sda16 is actually /dev/sdb. I tried to mount /dev/sdb, also /dev/sdb1 to /dev/sdb15, all are useless.

I'm wondering if there is anyway of getting Linux to mount /dev/sda16 and higher partitions?

Thanks,

70.31.158.159 (talk) 02:22, 1 June 2009 (UTC)[reply]

Does it actually show up in /dev/? What happens if you view your hard drive in gparted (or fdisk -l)? --antilived^{T | C | G} 05:06, 1 June 2009 (UTC)[reply]

Linux only allows 16 (0-15) SCSI block devices. The SATA devices use a SCSI interface. If you look at the major and minor mode numbers of /dev/sda15, you'll see it is 8,15, and that /dev/sdb is 8,16. That's probably where you're seeing the suggestion to use sdb. Offhand, I can't think of how you could create a 16th partition on a SATA disk and use it in linux, other than use LVM instead of partitions. -- JSBillings 18:19, 1 June 2009 (UTC)[reply]

Thanks, that's what I found out on Google too. Apparently Linux is using SCSI for SATA, which has the stupid 15 drive limit. This makes me feel so angry. Normally things should work in Linux and not in Windows, not the other way around. Well, guess there's nothing I can do about it until they come out with a new libata or something. 70.31.158.159 (talk) 21:23, 1 June 2009 (UTC)[reply]

Compile interpretive language

Script

This relates to my last question here (to which i would like to say thank you to those who helped). Is there away to compile this script(the one above) and the programs it uses in to a nice little stand alone program?

Smileyhill (talk) 05:29, 1 June 2009 (UTC)[reply]

The reason this would be difficult is because you are calling several external programs. Unless those programs have available source code, it will be hard to link them into a single binary (I don't know if it's impossible to link an existing executable, but it isn't standard practice). Usually, linking occurs on object files, which would require source to build. Nimur (talk) 07:30, 1 June 2009 (UTC)[reply]

I'm not sure what the problem is. Is it that you want the script to run faster? Or is it that you want to make a single packaage that includes everything that's used? Or do you just not want people to see what's in the scripts? Personally I tink having a script like thaty is the best way to deal with something like this. I'd probably go for python but that is also an interpreted scrfipt and would involve even more dependencies! Dmcq (talk) 11:48, 1 June 2009 (UTC)[reply]

Comeau Computing, which makes some well-regarded C and C++ compilers, has ccsh, which turns Bourne shell code into C, which you can then compile. It won't link in executables called by your program, as far as I know (I don't know if that's even possible). --Sean 13:10, 1 June 2009 (UTC)[reply]

The source to these programs are available. What i am trying to do is make a nice little package that a not-so-tech-savvy person could use. And inevitable I'd like to build an automatic live CD similar to ophcrack but dealing with wifi instead. —Preceding unsigned comment added by Smileyhill (talk • contribs) 15:39, 1 June 2009 (UTC)[reply]

You can design a graphical front-end without merging the external programs together. A lot of graphical front-ends exist for command-line utilities. If you are writing a program in C, for example, you can use the exec("some_cmd_line_prog"); command to execute anything as if you were on the command line. Nimur (talk) 14:46, 2 June 2009 (UTC)[reply]

Restoring one PC with the restore disk of another

Here's the problem: My daughter's PC won't boot (Win XP professional, HP laptop). Starts booting, XP logo shows, then reboots, and reboots... It is heavily malware-infested. The hard-disk was ok, I backed up her files using Knoppix, and created a disk image with Partimage. Then installed Ubuntu (which, to my mind worked flawlessly), but she wasn't happy with the solution. So I've written back the old unbootable partition, and we're back to square one. I read a while ago here about the clamav live CD, so I tried that too (found and deleted 17 infected files), but the PC still won't boot. I've also tried safe mode, of course, identical symptoms. I've also tried re-installing win XP with an original XP disk and her activation key, but the installation program reports that the activation key is invalid.

Here's my proposed solution: The PC was bought through her school (which she now has left). Her former classmates have identical PC's. I assume that there is a menu item somewhere for creating a restore CD/DVD. If we created a restore CD on one of their PCs, would that CD be usable for restoring her PC, or would it already be customized with the activation key of the friend's PC, resulting in both PC's having the genuine advantage of being listed as pirated? I know the activation key is stored in a separate file (somewhere in \windows\system32, I think), would copying this file avoid any such problems?

Here's the question: Will it work? --NorwegianBlue^talk 10:37, 1 June 2009 (UTC)[reply]

And in case someone should ask, "Why don't you just contact the IT people at her old school?", I am aware of that option. --NorwegianBlue^talk 10:37, 1 June 2009 (UTC)[reply]

I'm not aware of any support solutions that allow users to make their own restore disks, but I may have a way around the infinite rebots. XP has a stupid response to BSODs - it reboots. So if it's during the booting process it gets stuck in an infinite reboot loop. You can, however, turn this "feature" off by pressing F8 during booting (same place where you choose safe mode), and then at least you get to see what the BSOD is about. But in general if you can't even get into safe mode it's probably a waste of time to fix. --antilived^{T | C | G} 11:27, 1 June 2009 (UTC)[reply]

Thanks. I'll have a look at it, but BSODs tend to be rather uninformative. --NorwegianBlue^talk 14:01, 1 June 2009 (UTC)[reply]

I think it's pretty common these days to put a recovery partition on the hard drive with the option to burn CDs. It's cheaper than shipping them. Obviously pressed recovery CDs are not keyed to a particular machine, and I assume burned CDs are the same, though I've never used them. It would be less of a support hassle that way. You don't need CDs for this, though, if the recovery partition is intact—are you sure there isn't a recovery process you can trigger in the BIOS?

I don't see why the XP disk would claim your key is invalid. If it came with the PC then it should work perfectly well for a clean XP install. If it doesn't then complain to HP or whoever is supposed to provide your tech support (the university IT people?). -- BenRG (talk) 14:19, 1 June 2009 (UTC)[reply]

There was no extra partition. I'll have a second look with knoppix if I can find any candidate files (.iso's, or large files/directories with names suggesting that they may be what I'm looking for). I used an installation CD that I bought separately, for a different PC. I think the reason the installation program rejected the activation key, is that the PC was OEM'ed to HP, whereas my installation CD was not linked to any particular system (and has its own activation key, that I'm saving for a PC that I'll buy shortly). We had a thread here some weeks ago where someone said that such combinations could lead to activation keys not being accepted. --NorwegianBlue^talk 15:15, 1 June 2009 (UTC)[reply]

Note that the recovery partition won't necessarily be visible from Linux (or Windows) because the BIOS may use low-level trickery to hide it before starting the boot process. I'd forgotten about the OEM versus retail problem. You can change a retail into an OEM disk by editing setupp.ini, as described here for example. -- BenRG (talk) 15:49, 1 June 2009 (UTC)[reply]

Excellent! I'll scrutinize the BIOS, and try the setupp.ini trick if I can't find a BIOS option. --NorwegianBlue^talk 15:56, 1 June 2009 (UTC)[reply]

[4] —Preceding unsigned comment added by 82.44.54.169 (talk) 11:28, 1 June 2009 (UTC)[reply]

Thanks but no thanks, 82.44.54.169. I don't think anyone here will want to try that one. According to the second google hit, it contains a trojan, there are no sites that I'd want to download executables from among the first several google hits, and of course no source code. --NorwegianBlue^talk 13:56, 1 June 2009 (UTC)[reply]

Well I tested it in a virtual machine before I used it on my computer, no problems so far going on two months. But I fully understand if you don't wanna use it for license reasons, I'm just saying I'm not trying to peddle trojans here. —Preceding unsigned comment added by 82.44.54.169 (talk) 14:07, 1 June 2009 (UTC)[reply]

No offense intended! I'm pretty paranoid about what I download, and would never download an executable that I didn't even know the origin of. --NorwegianBlue^talk 14:35, 1 June 2009 (UTC)[reply]

lol fair enough. From what I recall each vendor has their own way to creating the recovery cds. Some prompt the user after a few days, and others only allow one recovery cd to be made before the option is disabled automatically. —Preceding unsigned comment added by 82.44.54.169 (talk) 14:55, 1 June 2009 (UTC)[reply]

The easiest way to deal with a drive that won't boot is to attach is as a second drive to another machine. Because it's a laptop, you'd need to invest $4 to $8 in a cable to adapt from the smaller laptop pin configuration. Run a variety of virus and spyware removers against the sick drive. Don't forget that when you made the disk image, you included all the infections...one of which may have been a RootKit virus. Malwarebytes and RootRepealwould be my top choices for the scanning.

The original CD that came with the laptop would be the one to use. There should be TWO setup.exe files on the CD, one in the root and one inside the Windows folder. One is for new installations, the other for over-writing an existing one. One will accept the existing key, the other not.(Sorry, I don't have mine here to check for you).From memory, try the one inside the Windows folder first.

IF you get it going, immediately go to Control Panel - System - Startup&Recovery Settings, and turn off "Restart automatically" on system failure. It is best to keep this setting off on all Windows machines. KoolerStill (talk) 15:13, 1 June 2009 (UTC)[reply]

Thanks. Sorry for not stating explicitly that the XP installation CD I used did not come with the laptop (see my reply to BenRG above for details). I do understand that the disk image contains the malware, and I much prefer a fresh install to a malware removal in these circumstances, hence my original question. --NorwegianBlue^talk 15:30, 1 June 2009 (UTC)[reply]

Update: I've tried BenRG's suggestions. There was no BIOS/Setup option for re-installing. I created two XP install CD's where setupp.ini was modified according to the link BenRG provided (using a binary editor directly on the .iso). The first (where OEM at the end of the "ExtraInfo" line was replaced by "270") behaved identically to the OEM CD. The second (where OEM was was replaced by "335"), offered the possibility of repairing an existing installation, in addition to a fresh install. At this point, however, the disk contained an interrupted install with the "270"-disk. In this setting, the installation program reported that the CD key was invalid. It's late here, so I'll have to continue later, but the result was somewhat promising. I'll try and reinstall the malware-infested disk, and repeat with the "335"-XP-install disk, and see if the activation key is requested/accepted then. Thanks. --NorwegianBlue^talk 20:58, 1 June 2009 (UTC)[reply]

Query String and Anchor in URL

From memory, the HTTP standard does not allow for a query string (?...) and an anchor (#...) in a single URL. Therefore, http://mysite.com?foo=bar#abc is invalid as well as http://mysite.com#abc?foo=bar. Has there been any development in standardizing the inclusion of both in a single URL or is it still one of those "If the browser supports it, write for one browser" sort of things? -- kainaw ™ 14:47, 1 June 2009 (UTC)[reply]

I don't think that's correct - I believe your first example was valid and standard-compliant. This forum references IETF RFC 2396, and states that the fragment identifier (#foo) gets truncated first, and the rest of the URI is then parsed. I think most web browsers use these semantics for parsing web URLs. For example, see this link, which can use a fragment identifier and a query string. Nimur (talk) 15:08, 1 June 2009 (UTC)[reply]

Thanks. I am making up slides for a talk and I will correct them to show that the ...?...#... form is proper. -- kainaw ™ 15:37, 1 June 2009 (UTC)[reply]

At least, this link works, which, presuming Wikipedia is standards-compliant, could be relevant to your question. Jørgen (talk) 16:25, 1 June 2009 (UTC)[reply]

pasting from word 2003 into outlook 2003

I have a template email that I use alot that is formatted in arial. I keep it stored in a word file, and when i need to use it i cut and paste it into a new email in outlook. everytime i paste, the text: "Monday through Friday, 9AM to 5PM Eastern Standard Time." comes out as times new roman, and i'm really tired of wasting my time reformatting that one line of text everytime I use this email. how can i fix this so it just pastes in arial like its supposed to? --Shaggorama (talk) 16:14, 1 June 2009 (UTC)[reply]

There may be a blank area between the main text and the troublesome line, which is formatted in Times Roman. Coupled with a glitch in Outlook that doesn't pick up the change back to Arial.So in the original, highlight the entire template document, change it something else, then change it back to Arial. This guarantees only one font instruction for the whole text. If the troublesome line is in a footer, move it out into the main body of the document and remove the footer. KoolerStill (talk) 23:14, 1 June 2009 (UTC)[reply]

Nicely done: you sir are a gentleman and a scholar. Thank you kindly for saving me about 15 seconds on each of hundreds of emails I need to send out (that shit adds up fast!). I only wish I'd asked a month ago. --Shaggorama (talk)

Hey...so turns out that only worked temporarily for some reason. There appears to be some sort of autoformat acting on the text on the clipboard. I suspect it has something to do with the date words (monday, friday). --Shaggorama (talk) 17:42, 2 June 2009 (UTC)[reply]

I don't know if this would help, but Windows Live Mail is free and pretty good. I use it myself. 99.224.125.166 (talk) 20:24, 2 June 2009 (UTC)[reply]

Anonymous delegate methods in C#

In C#, it's possible to use anonymous delegate methods this way:

static delegate string Process(string original);
private static void Perform(Process process) {
  Console.WriteLine(process("Hello world!"));
}
public static void Main() {
 Perform(delegate(string original) { return original; });
}

This will output "Hello world!". But is it somehow possible to use the already defined delegate type name instead of repeating the definition, like this?

static delegate string Process(string original);
private static void Perform(Process process) {
 Console.WriteLine(process("Hello world!"));
}
public static void Main() {
 Perform(new Process(string original) { return original; });
}

I've tried it the above way, but it doesn't even compile. Is there some other way? JIP | Talk 18:28, 1 June 2009 (UTC)[reply]

Who is

In Buddy memory allocation it states that - "...was independently developed by Knowlton ". Does anyone know more specifically who Knowlton was, ie a first name..

Also as an aside - for a compiled language - with dynamic variables - is it almost certain that buddy memory allocation will be used for these variables? Also do (some) languages actually specify data allocation types, or is it up to the compiler writer more generally? Also are there any more memory allocation mechanisms apart from the two mentioned at Dynamic memory allocation? Thanks77.86.10.194 (talk) 19:19, 1 June 2009 (UTC)[reply]

I'm just writing this as a Googler and not a subject matter expert, but at this Google Book page, I searched for "Knowlton" and on page 85, it says, The (binary) buddy system was originally described by Knowlton [11,12]. Footnotes 11 and 12 in that book are for a Kenneth C. Knowlton for two articles in Communications of the ACM, from 1965 and 1966. We have an article Ken Knowlton who's a computer science pioneer; I will bet they're the same individual. Tempshill (talk) 19:25, 1 June 2009 (UTC)[reply]

Unless there are two Kenneth Knowltons I think you're right. Thanks. I've altered the article but not the biography.77.86.10.194 (talk) 20:49, 1 June 2009 (UTC)[reply]

Difference between language itself and standard library

In a compiled, structured, statically-typed language such as C, I've always instinctively understood the distinction between the "language itself" and its standard library. But both are officially a fundamental part of the language as a whole. How to make a formal distinction between them?

For simplicity's sake, consider only C. As an example, the "language itself" includes operators such as +, =, ->, sizeof and so on, and constructs like if, while, return and so on. The standard library, however, consists of, for example, functions like printf, strlen and so on, and headers such as >stdio.h, string.h and so on.

The distinction I know instinctively is that modifying the "language itself" involves modifications to the language's parsing and tokenisation rules, but modifying the standard library merely involves modifying the library files supplied with the compiler. However, both are equally defined as standardised, and at least in case of C, the standard allows the standard library to be "magical" - i.e. not actually included as separate library files, but handled internally by the compiler itself. Is there a formal distinction between the two, or do I simply have to use the instinctive distinction I mentioned above? JIP | Talk 20:29, 1 June 2009 (UTC)[reply]

Your instinctive distinction is pretty much on the money. However, in practical terms, the standard library is a 'lesser' part of the standard than the language specification itself...it's kinda optional.

The standard library isn't necessarily present in all implementations - and if you don't want to use it, you can certainly exclude it from the linking stage and everything should still be OK. In other words, the compiler shouldn't make calls to the standard library 'behind the scenes' unless you tell it to. In C, for example, if you are writing code for some tiny little embedded microcontroller (something like the Arduino computers I'm using in refurbishing my home-made CNC milling machine) there may not be a standard library implementation at all. In the case of the Arduino, it has so little RAM and ROM/flash that being stuck with the standard library would literally leave you no room for your own program...and on a machine with no screen, no keyboard and no disk drives, it makes very little sense to have all of that I/O stuff lying around. Hence, no printf and probably no strlen either. However, on a 'normal' computer - you have a reasonable expectation that the standard library exists - and if it does exist, that it conforms to the standard.

Even in C, the standard library isn't allowed to be all that magical. I certainly can deliberately omit to '#include <stdio.h>' - and then proceed to write my own function called 'printf' that does whatever crazy thing I want it to do.

However, for the language to be called "C" - even on some pathetic little microcontroller, you should be able to assume that all of the LANGUAGE features are there. But - of course - there are often liberties taken with that on teeny-tiny machines. For example, I can tell the version of GCC that compiles C for the Arduino to disallow all floating point operations in order that the floating point emulation library isn't compiled into my code (which is just as well because it takes up about half of the poor things' memory!)...however, when you do that, what you have is an incompatible C subset...not a proper implementation of the C language.

But this distinction is pretty minor - if you have Windows, Mac, Linux, Solaris or BSD - any mainstream computer with a proper operating system, then you have every right to assume that the standard library is there and works exactly like the specification says it does.

SteveBaker (talk) 20:53, 1 June 2009 (UTC)[reply]

Be careful defining printf() yourself — C99 says that all standard library identifiers with external linkage must be the only things with such linkage, regardless of #includes. Apparently you're safe if you keep them internal, but I'm not entirely sure that standard headers aren't allowed to implicitly include other standard headers for you. --Tardis (talk) 20:01, 2 June 2009 (UTC)[reply]

In C, the distinction is there, but as Steve says really everything in C is optional (and as all sane C programs are system programs and all real system programming environments are one kind of weird or another) then the distinction is blurred. In practice it's more so; the "preprocessor" used to be a real thing, now it's subsumed into the lex parse of any serious C compiler (so sizeof is a compiler intrinsic, and really neither a preprocessor nor library object). memcpy() should formally be in the library, but many compilers (certainly gcc and msc++) just inline it, and the syntax phase of gcc knows all kinds of stuff about the format arg of printf that really break the notion of a formal boundary between it and the actual gnu libc implementation. Things are similarly incestuous in memory allocation land, and setjmp/longjmp (which knows things about how the compiler lays out stack frames that a mere library has no business knowing). Things in Java re much more incestuous (and I'd be surprised if C# is any different); java.lang is either implemented in C or is just part of the VM (and really there aren't genuine .class files or in-memory class objects for it, although the reflection API will fake java.lang.reflect.Class objects for things if you ask it), and the intimacy extends into java.util, java.util.event, subpackages of java.lang, and a bunch of native stuff; JNI acts as a cordon sanitare for the native C/C++ stuff that implements natives for other core java things like AWT - without it all kinds of supposedly library stuff has to know details of the VM implementation (and vice versa). 87.114.167.162 (talk) 21:20, 1 June 2009 (UTC)[reply]

When writing code for small embedded processors (or softcore CPUs on FPGAs), it is common to have no room for the standard library in the instruction memory space (try fitting malloc() into 4 kilobits of .text memory!) If you ever have the (mis)fortune of working with one of these tiny processors, you will very quickly need to distinguish between language constructs and included libraries. Many "simple" operations will actually start linking in hundreds of kilobytes of external code. Further, some system libraries will provide features like floating-point software emulation which are so basic, you probably never even thought of them as residing outside the C language specification. (Floating point numbers are actually "required" by the ANSI C specification, but their implementation may require a system library if the hardware has no floating point unit. Then, the distinction between "language" and "library" gets very blurry). Nimur (talk) 14:59, 2 June 2009 (UTC)[reply]

How to get a new graphics card to work?

Okay, that title is kind of misleading, because I think the card is working, but I don't think it's working well...

My g/f has a Dell Inspiron 531s with Windows Vista installed. We recently upgraded both the RAM and graphics card. Now, it has 4 gigs of RAM and an NVIDIA GeForce 8400 GS (256 MB). Not the most high-end card in the world, but the selection was limited by the fact that it needed to be half-height due to Dell's "slimline" tower. We chose that card because the card on my computer is similar (GeForce 7600 GT 256 MB) and it handles World of Warcraft just fine with only 2 gigs of RAM. Also, the reviews for the 8400 GS included several people saying it handled WoW fine, and since that's her game of choice, we figured we'd be set.

Well, everything installed fine -- the monitor is plugged into the new output port and everything displays fine. I checked the device manager in Windows and confirmed that the new card showed up under display drivers. We also downloaded and installed the most up-to-date display drivers for her card. But WoW's performance hasn't improved any ... in fact, it seems about as it was before the upgrades, even with all the display settings turned all the way down. I'm not sure what the problem is, exactly. I'm not looking for it to be perfect, but I'd expect the performance on her machine to be at least about the same as on mine, especially with the additional RAM.

So, any suggestions on what might be wrong? The graphics card the computer came with is integrated into the motherboard, I believe, so I guess it's possible it may still be using that instead of the card in the PCIe slot. But if that were true, how would things display at all with the monitor plugged into the new graphics card port? Also, I tried going into the BIOS, but I don't see any option to disable the onboard graphics adapter.

Thanks for your help... Dgcopter (talk) 22:44, 1 June 2009 (UTC)[reply]

If there's no option to disable the onboard video, generally that means the motherboard logic will disable it if it sees a valid looking videocard in the PCIe slot. I'd check the GeForce control panel thing and make sure it's not overriding the WoW settings (I don't have one to hand, but they do have a bunch of complicated settings in there for who gets priority, and it's almost always sensible to let the application decide. Are you driving the monitor (which I presume is an LCD) at its native resolution ? - try changing (upping) the resolution - sometimes you end up forcing the graphics card to run at a resolution or in a mode for which it isn't suited (forcing it to fall back to slower operations). Now see if it's set with frame-sync (vsync) on; if so, try turning it off (vsync should merely limit the frame rate to the monitor's already very high rate, but occasionally the handshake can mess up and you're left with a weirdly slow framerate). Remove any KVM switch you may have between the PC and the monitor, as this can mess up the VESA/DDC communication between the two, making for weird settings. Force the display driver and wow to restore to defaults. If all else fails, uninstall the driver, reboot (probably twice), then reinstall the official nVidia driver (not the one that came with your card).

Of course, all of the above assumes that the problem has anything to do with the video (rather than it just being where you're seeing it); verify that (both with and without WoW) that there aren't any suspiciously cpu-eating processes showing up in the task manager. 87.114.167.162 (talk) 23:07, 1 June 2009 (UTC)[reply]

Thanks for those suggestions -- I'll try what you suggested. You did say one thing, though, that went over my head (due to a general ignorance of hardware matters): Remove any KVM switch you may have between the PC and the monitor... Could you explain what that means? I'm not sure what a KVM switch is... Dgcopter (talk) 23:40, 1 June 2009 (UTC)[reply]

See KVM switch. Tempshill (talk) 02:52, 2 June 2009 (UTC)[reply]

I second the advice to reinstall the device drivers, but completely uninstall all nVidia drivers first, reboot, reboot again, install the new ones, reboot yet another time and all should be well. WoW really isn't a GPU intensive game though, personal experience and much lurking on the WoW forums lead me to beleive the CPU has a much larger impact on performance than any other component of your system. What kind of frame rates are you seeing though? Dalaran on a busy day and full on 25 man raid combat will slow just about any system down! 161.222.160.8 (talk) 23:45, 1 June 2009 (UTC)[reply]

I'll try the uninstall/reinstall trick. Regarding the framerate -- not sure, as I haven't witnessed the performance of her computer first-hand since she we installed the new card & RAM (was only a couple of days ago). My computer manages a fine framerate even in Dalaran and on 25-man raids -- I haven't bothered to check to see how much exactly, but it's not noticeably slower in those situations than anywhere else. I think our computers have similar CPUs, but I could be wrong. Dgcopter (talk) 00:00, 2 June 2009 (UTC)[reply]

Hate to break it to you but the 8400 you have bought is actually a little slower than the 7600 GS that you previously had. The majority of the 8 series cards were actually pretty awful for their numbers, except the 8800 series. Refer to this for a source - Tomshardware benchmarks. Nontheless I can recommend some things to do with WoW - if any addons are installed see if you can find lighter replacements, for instance if you use Questhelper or Carbonite you could replace it with LightHeaded and Doublewide ( here ). Also try turning shadows and view distance down, these seem to be the biggest FPS killers in the game. Gunrun (talk) 09:12, 2 June 2009 (UTC)[reply]

To clarify, I didn't replace the 7600 with the 8400. The 7600 is currently in my own computer. The 8400 is in my girlfriend's, which is definitely an upgrade from the 64 MB integrated POS that the machine came with (don't remember the brand at the moment). Dgcopter (talk) 14:01, 2 June 2009 (UTC)[reply]

Why not post this issue on the WoW technical forum? There are people there far more qualified to help with this kind of problem. BTW I think you should have spent a little more on at least the 8600. Sandman30s (talk) 20:05, 2 June 2009 (UTC)[reply]

June 2

Microsoft Excel

Does anyone know if Excel has some type of function to (easily) achieve what I am looking for? Let's say that I have a spreadsheet. I am recording data for 4 people for 7 days of the week. (This is just an example that I am greatly simplifying for purposes of this question.) Therefore, my (example) spreadsheet goes 7 columns across (Sunday, Monday, Tuesday, etc.) ... and it goes 4 rows down (for Person A, Person B, Person C, etc.). So, it basically looks like this.

Name	Sun	Mon	Tue	Wed	Thu	Fri	Sat
Ann	100	78	88	102	98	103	97
Bob	65	88	23	78	91	77	90
Cal	29	44	89	12	11	99	63
Deb	33	77	95	38	72	43	52

Now, after I have completed the spreadsheet --- and entered a ton of data --- I decide that I want to "switch" the rows for columns, and vice versa (the columns for rows) ... so that the spreadsheet looks like this. (For this fake spreadsheet, the numbers here are all fake ... and do not correctly correspond from the first spreadsheet to the second ... I just typed in any values.)

Day	Ann	Bob	Cal	Deb
Sun	100	78	88	102
Mon	65	91	77	90
Tue	12	11	99	63
Wed	33	77	95	52
Thu	83	67	43	12
Fri	34	71	25	88
Sat	71	70	86	28

Does Excel have some easy way to do this switch? Or do I need to construct / design a whole new spreadsheet from scratch? I only know the very basics of Excel -- nothing fancy or intricate -- so please keep answers pretty basic without a lot of foreign concepts / technical jargon. Thanks. (Joseph A. Spadaro (talk) 03:03, 2 June 2009 (UTC))[reply]

It has been a long time since I've used Excel, but I remember there being a "Transpose" option somewhere that does exactly this function. A quick search says it's a Paste Special option: Transpose Excel data from rows to columns, or vice versa. --Bavi H (talk) 03:41, 2 June 2009 (UTC)[reply]

Try copying the original table, click "paste special" and check the "transpose" checkbox, Excel will paste the values transposed. It should work, unless I misunderstood your problem. 93.108.139.109 (talk) 13:19, 2 June 2009 (UTC)[reply]

Cost of Printing

What is the price per page of with regard to ink? Alternatively, how many pages per ml can you print? —Preceding unsigned comment added by 90.194.110.63 (talk) 13:54, 2 June 2009 (UTC)[reply]

This all depends on what sort of documents you are printing, and which model of printer. Full-page color photos will take a lot more ink than double-spaced black type (words only). You touch on an interesting question; there are many inkjet printers that are remarkably cheap, which are sold in the hopes that the manufacturer will make money by selling you inkjet cartridges. This link (an ink usage comparison of three printers) claims that if you multiply the ml capacity by the cost of some print cartridges, it appears the manufacturers are selling ink for US$5,000 to US$10,000 per gallon. If you Google "inkjet printing cost" you'll find articles like this one that try to compare laser printers vs. inkjet printers — they looked at a couple of laser printers and worked out that because of the higher cost of inkjet ink, it was about 8 times as expensive to use the inkjet, if you end up printing 40,000 pages. Tempshill (talk) 14:15, 2 June 2009 (UTC)[reply]

Say I wanted to print normal A4 with normal word margins, no paragraphs, just pure text, how many pages would I get from a 8ml ink cartridge? —Preceding unsigned comment added by 90.194.110.63 (talk) 14:59, 2 June 2009 (UTC)[reply]

This article (http://www.creativepro.com/article/under-the-desktop-getting-a-handle-on-ink-costs) sheds some light. ny156uk (talk) 20:32, 2 June 2009 (UTC)[reply]

TCOP depends on:

The toner or ink coverage per page or the average per job; for color printing you need to know the coverage per color
The cost per page of other user replaceable items— most laser printer require a drum, transfer unit or waste toner unit
The cost per page of the printing media; i.e. paper
The cost of printer maintenance— some printers require that parts are changed on a regular basis, such as the fuser, transfer roller and feed rollers

The hard part is to calculate the coverage. I use a special laser printer to directly measure toner coverage. Without some similar tool, you would have to make a guess. The ISO/IEC standard for monochrome toner cartridge yield uses a page at 5% coverage. Heavier graphics increases the coverage and lowers the yield. ---— Gadget850 (Ed) ^talk 21:09, 2 June 2009 (UTC)[reply]

parallel processing..........

I found that in year 2005/2006 January/February Examination,1 of the question is very difficult for me to answer it ... can anyone give some point or information to me??

The question is : "With the aid of a diagram,explain how parallel processing affects the speed of computer processing?"

Hope got someone can help me to solve this question and show me the diagram that related to your information/points... i will feel appreciate to you... hope will get your reply soon... Thank you for viewingBebezaii (talk) 16:59, 2 June 2009 (UTC)[reply]

Have you read Parallel computing? There are lots of diagrams in that article. You might want to draw a Speedup plot, which usually shows the number of parallel nodes on the x-axis, and the resulting speedup (1 over the total execution time) for a test program. There are a few possible behaviors. No speedup means that the program is not parallelizable, and will have a flat line on this plot. Linear speedup means that the program is exactly parallelizable, and will have a diagonal line with slope 1. Superlinear or sublinear speedups are also possible, and indicate that the parallelization either created some new work or eliminated some work compared to the sequential program. Nimur (talk) 17:27, 2 June 2009 (UTC)[reply]

i now know need what diagram already... but i still confuse with the question... i ask my teacher already... she say need to explain how parallel processing affects the speed of computer processing.. minimum need 4 point with one diagram to support the 4 points... now my problem is dunno what is the point.... can anyone explain to me in the easy way.... or give me the answer and explain why you write the answer like this.. maybe in this way i can understand more easy.. Honestly,I got a presentation on next tuesday about this question.... i very scare now because i have to send my slideshow to my teacher after 2 days.. my time is getting short now... i wish someone can give me a hand to answer this problem.... i will appreciate the kindness people very much... i need done my slide show before this friday.. please help me to pass over my difficulty time at this movement... hope will get your reply soon... Thank you very much!!! —Preceding unsigned comment added by Bebezaii (talk • contribs) 03:33, 3 June 2009 (UTC)[reply]

English is not your first language, so let me explain as simply as I can. You know the expression "many hands make light work"? It means the same thing when many CPU's are used to do calculations together. Let's take a simple example - the work a CPU has to do to sort a list of data. Suppose the list contains 1000 rows - easy for one CPU to sort right? Now suppose it contains 1 BILLION rows - much more difficult for one CPU and it probably needs a lot of memory and temporary writes to disk etc. Now break that list down to a few million each and imagine lots of CPU's each doing their own sorts - then merging the list finally. That's the power and speed of parallel (many) computing. Sandman30s (talk) 07:15, 3 June 2009 (UTC)[reply]

o... is it means parallel processing affects the speed of computer processing is because it can break down the data into few part so the computer can sort the data easy and used less time to sort it,so the speed to sort the data is more faster than a computer sort the data without using parallel processing...then finally combine all the data to one again is it?? by the way i want to make sure one thing... parallel processing can also write as parallel computing right??is it the same?? i will waiting for your reply... thank you for the information!!

Sorting isn't the best example for parallel computing, since the end result requires a single sort. Perhaps a better example is a render farm. In the case of a render farm, you need to generate the animations for each frame of the movie. Since each task (rendering a frame) is independent of others, you can simply spread out the work across many different computers, and then assemble them together once they've all completed. That's an example of a very simple parallel process. Not all parallel computing is quite a simple as with a render farm (something we like to call Embarrassingly parallel). A lot of parallel programming requires communication between the individual units to proceed to the next step. -- JSBillings 12:25, 3 June 2009 (UTC)[reply]

Firewall problems

Upon loading my Desktop PC, desktop is loaded, AVG is up and running etc, after about 2 minutes it pops up that my firewall is not turned on or active and that my PC is at risk(potentially) Its XP SP3 but when i click on the balloon to "resolve" the problem it indicates that windows firewall is already on and running. Is there any reason it doesnt seem to load straight away or am i at any risks as i can run the internet for the 2 minutes before this problem flags up, or even run any non internet programmes. Thanks for any help --CorrectlyContentious 18:10, 2 June 2009 (UTC)

I don't have a solution, or even know if there is a brief exposure, but I have this issue too. --Jc3s5h (talk) 19:25, 2 June 2009 (UTC)[reply]

My friend's computer had this symptom too. I downloaded and installed Avast and Spybot, both of which found some problems which the respective programs fixed. On his system, I still need to cleanse a few more stubborn items, but the "firewall not turned on" message seems to have gone away. I'm afraid I don't have the logs available right now to be more specific on the problems found. --LarryMac | Talk 19:44, 2 June 2009 (UTC)[reply]

Does the warning pop up again after the first time? If so, run a scan for spyware (Spybot is good). If it's only once, that is a function of Windows not fully recognising AVG as a firewall (it is looking for its own built-in one). Go to My Computer, right click, choose Manage, then choose Services & Applications, Services. Look for "Security Centre". Right click in, choose Properties, then use the drop-down box to Disable it. This will stop the complaint. Naturally, make sure the AVG real-time mode is on.KoolerStill (talk) 22:30, 2 June 2009 (UTC)[reply]

Ubuntu script testing

I have 2 programs on my talk page. I was wondering if some people who have some experience with Aircrack-ng could test this code with their systems. This program works perfikly on my system (My system is Ubuntu 9.04 running Gnome with a Broadcom chipset.) I don't have access to any other wifi cards to test this on. Thank you Smileyhill (talk) 21:33, 2 June 2009 (UTC)[reply]

Fully automatic Aircrack-ng

This kinda relates to my question here. Thanks to Mr. Anderson's code i have written a program that can automatically start attacking all WEP wifi networks near by, Or can just attack one target. _{Can be found on my talk page}. What i would like to do is to make a live CD that contains this program, I was thinking about modifying a BackTrack live CD but i don't know how to customize a live CD like that. So how would i go about doing this? Smileyhill (talk) 21:16, 2 June 2009 (UTC)[reply]

An alternitive that i'd be happy with would be to take an already installed OS and make a live CD with that installed OS's setting / programs and so on. —Preceding unsigned comment added by Smileyhill (talk • contribs) 22:10, 2 June 2009 (UTC)[reply]

June 3

Cheap computer parts

Okay well here is my dilemma. I want to build a cheap computer that I can use just to surf the internet and I was wondering if anyone had any sites to get some cheap parts. I just want to spend like 100 bucks to build it. If you have anything I would really appreciate it. Thanks guys RandomAccessDawg (talk) 03:27, 3 June 2009 (UTC)[reply]

If you are buying new (or even if you go for second hand) $100 will probably not even be enough for just a case and motherboard - two of your most basic components. http://www.newegg.com/ is a good site for the US (although I am from the UK so others might have better suggestions). --Joe^Talk_Work 03:58, 3 June 2009 (UTC)[reply]

Well I am currently in the process of getting a job so when I do I will probably be able to spend more. What would you think would be a reasonable price for a cheap computer? I am planning on putting the latest Ubuntu on it so the OS will be free. But ya I didn't look at newegg yet but I was planning on it. Thanks man! —Preceding unsigned comment added by RandomAccessDawg (talk • contribs) 04:07, 3 June 2009 (UTC)[reply]

If I were you, I would look on Craigslist in the "computer" category, where sub-$100 computers are common. They will be early Pentium 4 systems with monitors and not a lot of RAM. Be sure to try it out for a few minutes on your favorite websites to see if performance is OK before you pay the money and walk away with it. Tempshill (talk) 04:23, 3 June 2009 (UTC)[reply]

Yeah, to be sure, you can find computers that will easily surf the web and do lots of stuff for < $100. But finding someone parting with those can be tough. Most non-savy people think their computers are worth a lot more than they are, and most savvy people either keep them around, or don't even bother selling them. Even eBay tends to have really overpriced low-end machines. That said, I think eBay might be a good place to start so long as you're somewhat discriminating about pricing. Same thing for craigslist. I'd say garage sales too, but I think that might be too much time invested for the payoff.

Hopefully you can find working peripherals. Just make sure you know how a monitor and keyboard attach, and a network card too. USB is a definite plus for the latter two. Shadowjams (talk) 04:52, 3 June 2009 (UTC)[reply]

Also, the entry price point on some low end machines (those new non-windows laptops) is < $300. Shadowjams (talk) 04:55, 3 June 2009 (UTC)[reply]

What is Kerberos used for?

Hi. I understand that Kerberos is an authentication protocol. But where have I seen it in action? I searched Google and even read your entry on the subject, but haven't found an answer. Your entry says that it is the default authentication protocol for Windows 2000 and later, but it is a network protocol. I log on to all kinds of servers through FTP, HTML forms, RDP, SMB, etc. Are those all using Kerberos to authenticate me?--76.120.121.128 (talk) 06:04, 3 June 2009 (UTC)[reply]

At the risk of over-simplifying with an analogy, Kerberos is like a government agency that issues an ID card such as a driver's license that is generally trusted by others as reliable proof of identity. When you applied for your ID card, you likely needed to provide a primary evidence of identity, such as a birth certificate. (Well, lets assume you did.) The ID card is then used as a reliable secondary evidence of your identify for the purposes of bank transactions and other business activity. I may not know you, and I may not even have the expertise to verify the authenticity of your birth certificate, but I have full faith in the reliability of that government ID. The point is that you do not need to carry your birth certificate with you everywhere, and I only need to be able to recognize and accept one reliable form of identification.

The birth certificate would be analogous to your username and password that you use to log into the network. The government agency would be the Authentication Server. The ID card would be the credentials (Ticket-Granting Ticket) issued by Kerberos that presumably cannot be forged. Banks and other businesses would be the other computers on the network that provide protected services such as file servers, database servers, and internet proxies. These other computers are not going to trust your computer directly to verify your identify, and may not even have the ability to verify your password if you supplied it. Instead, they trust the credentials issued by the authenticating server, and then only under well defined conditions. The point is, you enter your password once, and the entire network recognizes who you are.

And, by the way, all the sensitive Kerberos communications are performed using encryption methods that are designed to ensure the integrity of your credentials and to prevent non-authorized persons from hijacking your identity (i.e. forging or copying your ID card). -- Tcncv (talk) 07:18, 3 June 2009 (UTC)[reply]

ok. Thanks for that. But, where have I used it? I have used browsed things like network printers and network shares inside Windows. I noticed that I am asked for a password, but am logged in automatically on subsequent visits. Is that done using Kerberos?--76.120.121.128 (talk) 08:18, 3 June 2009 (UTC)[reply]

Not necessarily. Are you using Active Directory? -- JSBillings 11:29, 3 June 2009 (UTC)[reply]

Junk Mail Sent by Me

Over the past year or so, my email inbox has received several spam emails sent "by me." I realize that the send address is spoofed, but... Is my email address being used as a 'from' address for your spam? 96.227.82.128 (talk) 09:07, 3 June 2009 (UTC) I really want to get these fuckers![reply]

The from section can be easily forged and chances are the program the spammer is using is just set to make the from section the same as the to one. Your email address probably isn't being used by spammers. edit: If it was you might be getting lots of failed delivery messages or something, from the spammers sending mail to places that don't exist or outright refuse it.Gunrun (talk) 09:13, 3 June 2009 (UTC)[reply]

See Email#Header_fields

..Also note that the "From" field does not have to be the real sender of the e-mail message. It is very easy to fake the "From" field and let a message seem to be from any mail address..

You can assume that the spam email recieved from other senders has the 'from' faked too. Why email/internet service providers allow this to continue is a mystery to me. Put me down on your lynch mob - they definately ~~deserve~~ need a hard smack.77.86.10.194 (talk) 11:36, 3 June 2009 (UTC)[reply]

Z80 question

In Zilog_Z80#The_new_syntax it says that "..except for the mnemonic “jp (hl)”, which is inconsistent.."

I've tagged it with 'clarify' in the text - is this true or just creative vandalism? Thanks77.86.10.194 (talk) 09:36, 3 June 2009 (UTC)[reply]

Funny floats?

I'm experimenting with a program that works with numbers - and I was trying to find out what sort of system it uses to store the numbers. I found that it could store 2^n+1 without losing the "1" up to about n=53, so I guess 53bits for mantissa. I also found that it could store up to 2^1023 as a number and that it also handles higher values as "infinity" - so I thought 64bit floats right??

Then I tried 2^-n - it gives answers for up to 2^-1074 (7 is not a typo) it evaluates

2^-1073 as 9.88131E-324

2^-1074 as 4.94066E-324 (corrected twice)

2^-1075 as 0

2^-1024 as 5.56268E-309

2^-1023 as 1.1125E-308

2^1023 as 9.98847E+307

2^1024 as "infinity"

the actual values seem correct? What is going on here? Any ideas?77.86.10.194 (talk) 11:12, 3 June 2009 (UTC)[reply]

This looks like double precision with denormal numbers near 0. PrimeHunter (talk) 12:34, 3 June 2009 (UTC)[reply]

Grand Celebration

i am interested in buying the ship Grand Celebration from the owner when it is to be scraped

@@ Line 764: / Line 764: @@
 :This looks like [[double precision]] with [[denormal number]]s near 0. [[User:PrimeHunter|PrimeHunter]] ([[User talk:PrimeHunter|talk]]) 12:34, 3 June 2009 (UTC)
+== Grand Celebration ==
+i am interested in buying the ship Grand Celebration from the owner when it is to be scraped