Wikipedia:Reference desk/Archives/Computing/2008 October 10

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October 10

My trashcan has gone missing !

My "trashcan" or "recycle casket" or whatever to call it has suddenly gone missing from my desktop.. Almost as if it has been deleted. And I can say I certainly haven't deleted no trashcan!

This is a problem coz i can't find it again anywhere and im a bit clueless as to what to do. And i don't know/rememebr what it was called exactly so I havent been able to 'search' my harddisc either for it.. hopefully it is just the shortcut that has gone missing from the desktop, but i just dont know...

what might have happened? and more importantly - how to fix it and find it and/or restore it?

thanks —Preceding unsigned comment added by Krikkert7 (talk • contribs) 00:07, 10 October 2008 (UTC)

Well, My first guess would be that you accidently moved the recycle bin off the screen somehow and lost it. The simple way to fix it in that case is re-align the desktop by rightclicking and arrange icons by whatever. Then grab your recycle bin and re-arrange how you liked your desktop. If it's more complex then that then please reply with information. Forai (talk) 00:23, 10 October 2008 (UTC)

I think it is actually possible to delete the icon for recycle bin on windows xp or later. Did you accidentally press delete for it? 12.169.180.158 (talk) 01:49, 10 October 2008 (UTC)

If you are using Vista, you can right-click on the desktop and choose Personalize. Then click "Change desktop icons" on the left and you can get your Recycle Bin back. --wj32 ^t/c 02:16, 10 October 2008 (UTC)

Dont look for tech support here often. OK! To find your trash can, if its on the display but hidden? ( Right click on the desktop ) Arrange Icons by (Third option)Type. To UnHide it, run TweakUI Windows Power Tool. —Preceding unsigned comment added by 99.185.0.29 (talk) 06:33, 10 October 2008 (UTC)

thanks guys big time, with your help I got it sorted out! :D

Spyware

I am a complete retard and have managed to infect my computer with spyware. What good, free scanners can I use to get rid of it? Thanks in advance. 86.143.234.77 (talk) 02:18, 10 October 2008 (UTC)

Spybot search and destroy and AdAware are both good scanner. Just google 'em. --AtTheAbyss (talk) 02:28, 10 October 2008 (UTC)

The steps laid out here seem to be pretty solid (open the appropriate thread for you operating system). Yes they're recommending you run several scanners, but it's a good idea to do so if you've been hit. -- Consumed Crustacean (talk) 04:14, 10 October 2008 (UTC)

You are NOT a complete retard. Humans CANNOT MAKE MISTAKES! Only computers can. OK! If you computer is infected with spyware, you want to get a program called Spybot Search and Destory. [1].

Install it.

Run the Immunize function

Have it scan as the last thing you do during the day. ( it should take an hour or so )

Turn on Expert mode, and look at BHO's ( Browser HiJacker functions ) and click on each one. If one appears that you dont know what it does, type is SPID code ( looks like {EAD4891924-2120-1249 ) into google, and you can easily find if it needs to be deleted.

Just so you know, I got an email, and moused over the graphicl. Turns out it was a link to a codec downloader that loads a trojan horse.

What this means, is that anyone can be fooled, and Windows is inhearntly unsafe by design ----~~ —Preceding unsigned comment added by 99.185.0.29 (talk) 06:41, 10 October 2008 (UTC)

how to change from alphabet to ascii code?

i want to know ,how to change from alphabets to ascii code in c++ language. —Preceding unsigned comment added by 89.179.31.23 (talk) 07:26, 10 October 2008 (UTC)

With single quotes, like 'a' (not "a") --194.197.235.221 (talk) 09:13, 10 October 2008 (UTC)

Not sure what the question means. Most codes around now except EBCDIC have ASCII as a subset and nearly everything extra is extra because it isn't in ASCII, there are a few things which could be put to something similar but have different semantics. Give an example of an alphabet you would come from and what you would expect the result to be. Do you want to change to Unicode, e.g. UTF8 or UTF16 for instance instead? Dmcq (talk) 12:08, 10 October 2008 (UTC)

Generally (since almost nobody uses EBCDIC anymore) - and presuming we're talking about a non-internationalized program, letters are "already" in ASCII codes. So if you write:

 for ( int i = '!' ; i < '~' ; i++ )  // Run 'i' over the entire set of 'printable' characters
   printf ( "'%c' is %d\n", i, i ) ;  // Print 'i' as both a character and an ASCII code

...you'll get an ASCII chart printed out that starts with:

   '!' is 33
   '"' is 34
   '#' is 35

...and eventually...

   'A' is 65
   'B' is 66
      ...
   'Z' is 90

...and so on until we get to...

   '}' is 125
   '~' is 126

SteveBaker (talk) 13:09, 10 October 2008 (UTC)

IBM sells five gigabucks worth of EBCDIC-based mainframes each year, so somebody must be using them. A very miserable somebody, but still. --Sean 13:50, 10 October 2008 (UTC)

I'd be quite surprised if there were any C++ programs running on them though! SteveBaker (talk) 14:09, 10 October 2008 (UTC)

Why? My current project involves Java on the mainframe; I don't have any direct experience of C++ but I don't see why people wouldn't use it. 81.187.153.189 (talk) 10:04, 11 October 2008 (UTC)

I don't know about Java - but C++ on ZOS/OS-390 uses the ASCII character set. Some sort of EBCDIC-to-ASCII and ASCII-to-EBCDIC kludge is used on the inputs and outputs of the C++ code so it can run in a "normal" ASCII environment internally. I'd be quite surprised if Java for that operating system didn't do the exact same thing. SteveBaker (talk) 03:18, 12 October 2008 (UTC)

Yes, characters (or 'alphabets' as you call them) are stored as numbers (in ASCII codes). With printf you can choose to print the ASCII code as a character (%c) or as a number (%d) (simplistic explanation) --wj32 ^t/c 21:18, 10 October 2008 (UTC)

Converting ClearSpace markup to MediaWiki

Does anyone know of a package/plugin/whatever to convert documents in the Clearspace wiki markup (urgh!) to MediaWiki? SteveBaker (talk) 14:10, 10 October 2008 (UTC)

Scanning banknotes

Why can't banknotes be scanned? 14:31, 10 October 2008 (UTC)

They can — they just don't give an accurate reproduction when scanned. This makes it more difficult to forge them. -=# Amos E Wolfe ^talk #=- 14:52, 10 October 2008 (UTC)

Many photocopiers and computer programs detect the EURion constellation, a pattern present on many bank notes, and refuse to operate. That article also suggests digital watermarking may be used as well. -- Consumed Crustacean (talk) 14:54, 10 October 2008 (UTC)

Interestingly, photocopying American dollars is a felony, unless changed/enlarged/shrunk to the point that it is immediately obvious that it is a fake. Even if you never intended to pass the money as counterfeit, it's still illegal. --Alinnisawest,^{Dalek Empress} (extermination requests here) 00:47, 11 October 2008 (UTC)

Laptop Downloading Woes

I was given a troubled HP laptop computer to diagnose and repair that I can not find a solution for.

The problem it had initially was that it could connect to a network via cable or wireless and would show up with IP information, connected to IM programs, etc. but would not connect to the internet through a web browser. This turned out to be a problem with the a Norton program that apparently comes pre-loaded on HP systems.

So, now the laptop is connecting to browsers and everything seemed fine. Come to find out that I can not download anything from the internet to the hard-drive, such as a simple installer program. Any files will begin downloading like normal (ask where I would like to save, pop up the download window, etc.) but then just immediately complete and do not show up with any resulting download. The very first time I had this issue, I believe it actually downloaded for some time, completed, and left me with a fragmented file that could not be opened.

The laptop -will- download updates via Windows Updater, but I believe it will not allow me to download files from other programs, such as Zune Marketplace.

I have tried hooking this laptop to different networks (work network and home network), using different web browsers (FireFox, Internet Explorer, and Chrome), clearing the TCP/IP Stack via the command line, logging in as a Guest user on the computer, booting up in Safe Mode + Network, and have not been able to identify any firewall, anti-virus/spyware programs, or generic Windows settings that could possibly cause this issue.

The computer is using 32-bit Windows Vista Home Premium.

Does anyone have any suggestions?

209.253.35.194 (talk) 17:05, 10 October 2008 (UTC)Impen

As a temporary solution, try getting a download manager and resuming every time the download breaks. This might be an issue with your ISP, or with Norton security software. Have you tried disabling Norton antivirus/firewall? Also, by "not show up with any resulting download" do you mean the download doesn't show up in the download manager, or isn't present as a file on the filesystem? If it exists, how big is it? --wj32 ^t/c 21:23, 10 October 2008 (UTC)

The problem is that the download is not breaking - it is completing extremely quick. There is no download to resume, because the system thinks it has finished.

I know it is not a problem with an ISP, because I have tried it at two different locations with separate networks (home and work) and it is not a problem with Norton. I uninstalled any/all Norton related software I could find on the computer with the aid of the program they make you download to uninstall their software.

By "not show up with any resulting download," I mean it does not create any new file on the system. The option for "Open" and "Open Containing Folder" options are not available in the browser. It appears the downloaded file does not exist at all.

Also, I have tried this on a wired and wireless network.

Thank you for the input, wj32. =) —Preceding unsigned comment added by 209.253.35.194 (talk) 22:28, 10 October 2008 (UTC)

Try using IE and "Open"ing the file. Does it download properly? It might be that you can't write to the download location (very unlikely though). Also, what was the problem with Norton? Try going to C:\Windows\system32\drivers and seeing if any Norton-related drivers are still there. --wj32 ^t/c 22:46, 10 October 2008 (UTC)

I have tried "Open"ing or "Run"ing these fies when downloading with Internet Explorer and FireFox, and it does appear to work. The files I was trying to download previously may have been too small to determine whether they were actively trying to download or just cutting short (I didn't think they were, as my work network is typically slow).

After trying to download a few larger files to the hard-drive, it appears that the browser is allowing the downloads to make progress up to 100%, then immediately eliminating the download. The file does not appear on the system once the download progress is complete. This was the same result when trying to download to desktop, My Documents, or a USB thumb-drive.

I searched the C:\windows\system32\drivers directory for any suspicious looking drivers, but the esoteric nature of driver naming prevents me from really locating any that may have been associated with Norton.

I am not sure what the problem was with Norton, but it seemed to be a common issue with HP laptops pre-installed with the Norton software. —Preceding unsigned comment added by 209.253.35.194 (talk) 23:59, 10 October 2008 (UTC)

That's very strange... are you sure the file is actually present while the browser is downloading? Obviously, if the file is present, the browser can't be deleting the file (why would it do that?). --wj32 ^t/c 00:55, 11 October 2008 (UTC)

I tried downloading a larger file with FireFox and also with the Zune software. During these downloads, I looked in the folder they were transferring into to see if there was a temporary or any trace of a file being downloaded, and there was. Once the download was complete, the file was completely removed for some reason. The result was the same between the browser and the Zune software.

The Zune software even showed up with a new subscription (I was just downloading podcasts from the Marketplace, since they are free and sizely), got to 100% download status in the software, etc. I was unable to play these once they were downloaded or, as I was saying previously, locate them in the downloads folder specified in the Zune software.

Any other ideas?

64.244.94.114 (talk) 17:33, 17 October 2008 (UTC)Impen

Ubuntu download as VMware virtual machine, VMware tools preinstalled

Where can I download Ubuntu as a VMware virtual machine with VMware tools preinstalled, aside from the VMware website? I have an Intel Mac 10.5. The VMware website keeps 7zip archives of Ubuntu with VMware tools pre-installed, but the only one (of four files in the archive) which VMware Fusion can open gives me a Terminal only. (The 770MB "VMware Virtual Disk" remains untouched.) I successfully installed Ubuntu manually, and then I tried installing VMware Tools afterwards. But that doesn't work either. When it goes to configure itself, it seems to want a C-compiler, but can't find gcc even though it is installed. (Apparently, v4.2 is already installed.)

My solution is to download it, altogether, with Tools pre-installed. VMware Tools is software that runs in the virtual machine, to help it integrate better with the host system. I'm a noob, much as I make every effort I can to decipher what I can't understand!My name is anetta (talk) 17:53, 10 October 2008 (UTC)

In the guest, open a terminal and type sudo apt-get build-essential linux-headers-`uname -r`. Then install VMware Tools. Ubuntu comes with GCC, but without the essential headers. --wj32 ^t/c 21:27, 10 October 2008 (UTC)

Thankyou for your help, Wj32, but copied straight in it says "E: Invalid operation build-essential", and even when I change it to apt-get build-essential linux-headers -"uname -r", it says E: Command line option ‘n’ [from -uname -r] is not known. Even when I run it as root. I'll try again after updating the machine, however.My name is anetta (talk) 23:51, 10 October 2008 (UTC)

Oops, sorry! I meant sudo apt-get install build-essential linux-headers-`uname -r`. --wj32 ^t/c 23:56, 10 October 2008 (UTC)

You can get "Super Ubuntu" in a Virtual Machine (not an official version):

http://hacktolive.org/wiki/Download_Super_Ubuntu —Preceding unsigned comment added by 87.196.42.142 (talk) 01:38, 11 October 2008 (UTC)

Thankyou. Terminal is busy. And I'm torrenting Super Ubuntu as well.My name is anetta (talk) 11:16, 11 October 2008 (UTC)

Why memory segmentation?

We have an introductory course in microprocessors. In 8085, the data bus of RAM chip and microprocessor both are 8-bit and hence interfacing is straightforward. For 8086 however, data bus of processor is 16-bit and that of RAM chip is 8-bit. We can't have a 1MB ram chip in which we can address two locations at the same, hence we use two chips each of 512kb for interfacing to the 8086. This is also where the concept of memory banking comes in.

However, my question is - instead of going through all this hassle, why can't we have RAM chips with data bus of 16-bits? It would make the trouble of segmentation unnecessary. (For now, let's ignore the other advantages of memory segmentation.) My professor explained that it's a "hardware limitation" of 8086, but I don't understand how - if data bus of both processor and RAM is 16-bit.

Thanks --RohanDhruva (talk) 19:06, 10 October 2008 (UTC)

Doubling the size of a given bus is a lot more than just adding 8 wires; you need to double the number of parts for every part of the system that touch that bus. This uses real estate on the silicon die, which is always in short supply. Worse, particularly back in them days, chip design software was very primitive (making even trivial-seeming changes into a lot of hard work) and really Intel didn't employ all that many people. Plus I guess they thought (rightly, from an economic standpoint) that the 16/8 chip would sell perfectly well, and they could do a 16/16 chip later. I'm sure they came to regret that, from a technical standpoint, later - but by that time they had huge piles of 8086 cash, so it's hard to say they were wrong. Incidentally if they had made it 16/16 you wouldn't have needed 16 bit RAM chips - you'd just use two 8 bit ones in parallel and common their chip selects. -- Finlay McWalter | Talk 19:22, 10 October 2008 (UTC)

Additionally (in general; I don't know the specifics of the 8085->8086 transition) there are other reasons why a new chip might willfully inherit the limitations of its predecessor. These include the goal to be:

• pin-compatible, or as close to as possible, to minimise the effort designers have to put in to switch a given board from your old device to your new one
• instruction compatible, or at least very similar, so existing software works, or can be ported with less effort
• hardware compatible, so existing devices (like memory SIMMs) from the old system can be used in the new. Also remember that RAM isn't the only thing on a classic x86 system address/data bus - external devices like UARTs, mouse controllers, floppy controllers, and many more are all built to the same architecture standard; the less you change that, the more of these devices will work (or the easier it will be to make them work).

As with my first answer, the real reason is "economics". -- Finlay McWalter | Talk 20:13, 10 October 2008 (UTC)

Thanks a lot, Finlay! --RohanDhruva (talk) 10:52, 14 October 2008 (UTC)

Self-Replicating Program

How would one go about making a program that makes a random change to its programming based on a dictionary of commands and then replicates itself? Thank you. —Preceding unsigned comment added by Freiberg (talk • contribs) 21:48, 10 October 2008 (UTC)

You'll have to tell us what environment you're thinking of programming this in (or, if you have no constraints). -- Finlay McWalter | Talk 21:52, 10 October 2008 (UTC)

While I don't necessary care about the programming language used, I am hoping to not have it swamp my hard drive, perhaps by partitioning the hard drive. Also, I am hoping that any program that fails to replicate is deleted.--Freiberg, Let's talk!, contribs 22:20, 10 October 2008 (UTC)

Well, you want to build a virtual machine with a limited instruction set defined by yourself and have your "programs" run inside that virtual machine. Assumedly what you are thinking of is a kind of artificial life evolving through a genetic algorithm. See Tierra for an implementation of that. Equendil Talk 01:12, 11 October 2008 (UTC)

It's not that hard to do it in most languages. You could even do it in C++. Write a program that writes a copy of itself to disk - then runs the C++ compiler on the result - then runs the result and exits itself. That's not too tough - after that it's a matter of making the random changes...but the trouble with that is that almost any random change results in a program that won't compile. Hence the attraction of making a virtual machine with a limited instruction set (as Equendil suggests). The principle benefit of doing that is that you can arrange that (a) there are no "illegal" programs - they all run in some manner no matter what garbage they contain...and (b) that the ratio of 'useful' instructions in the instruction set to 'obscure, not very useful' ones is kept to a minimum to give the next generation. In that setting, you can make a single 'special' instruction that means "make a copy of yourself with N random alterations". Being able to control the virtual machine also means that there is no risk of "The Terminator" knocking on your door and telling you that a program evolved from your system will escape in the future and takes over the world enslaving all of humanity (never a good thing!). SteveBaker (talk) 01:38, 11 October 2008 (UTC)

Thank you; this is exactly what I needed to know. That was also exactly my intent, as I wanted to set goals and see what kinds of programs I could "breed". I now know.--Freiberg, Let's talk!, contribs 21:54, 11 October 2008 (UTC)

You may be interested in the evolutionary computation article. -- Finlay McWalter | Talk 21:58, 11 October 2008 (UTC)

I am indeed. Thanks. --Freiberg, Let's talk!, contribs 16:09, 12 October 2008 (UTC)

You may be interested in Nanopond. APL (talk) 01:18, 14 October 2008 (UTC)

"See what I did there?"

What does "See what I did there?" mean in the context of web forums or blogs (I'm asking on Computing instead of Humanities only because it seems like a web meme). From what I can tell from Google, it generally follows a dumb pun or play on words. Generally a really obvious one. Is the idea that people aren't clever enough to get the play on words? Or is there some sub-text or joke that I'm missing?

Thanks! Madd4Max 23:04, 10 October 2008 (UTC)

Google gave me this at Urban Dictionary. Algebraist 23:08, 10 October 2008 (UTC)

I've seen "I see what you did there." - but not the form you describe. It usually happens when someone posts a lame pun or a crappily photoshopped "joke" image - and the other person replies "I see what you did there." as a way to say "I acknowledge that you tried - but I didn't find that at all funny or original". SteveBaker (talk) 03:10, 12 October 2008 (UTC)

Well, I've seen it used (and have used it myself) to call attention to a genuinely clever remark or post that may be too subtle to be noticed and too good to waste. Kind of an egotistical move on the part of the poster - at least, in my case it is. Vonbontee