Wikipedia:Reference desk/Archives/Computing/2007 December 17

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December 17

Why do some kinds of malware, especially trojans, have weird names?

Like the Swizzor trojan, the Vundo trojan, the Zlob trojan. These are strange names. Why do they have these weird names. MalwareSmarts (talk) 02:04, 17 December 2007 (UTC)

Bored programmers. Generally, there is nothing to tell what name the original author gave to the virus - so generally the people at the anti-virus agencies who discover them just pick an arbitary name. Sometimes from the behavior of the thing - sometimes from some piece of text found inside the virus - sometimes just whatever pops into their heads at the time. SteveBaker (talk) 04:05, 17 December 2007 (UTC)

I think it might also be to confuse people who aren't that knowledgeable about computers - if you see zlob.dll you probably figure its some important system file, but if it was InternetWorm.dll people would probably catch on. This would be especially true with trojans, as they're supposed to remain unnoticed. —Preceding unsigned comment added by 199.111.211.113 (talk) 05:28, 17 December 2007 (UTC)

They are often purposeful names based on common Windows libraries. Hit ctrl-alt-del and look at the processes running in Task Manager. You'll see things like rdpclip.exe, csrss.exe and ctfmon.exe. Would you notice if you also had rcpclip.exe, csrs.exe, and clfmon.exe running? -- kainaw™ 13:11, 17 December 2007 (UTC)

A corollary to the original question would be - why do legitimate processes have such weird names? DuncanHill (talk) 13:14, 17 December 2007 (UTC)

This goes back to the stone age of computing. File names had two limits. There was the hardware limit (such as the 8.3 name limit in DOS: 8 character name and 3 character extension). Then, there was (and still is) the programmer's limit - how much is a programmer willing to type. Stack on top of that the requirement that processes have unique names (since object oriented programming wasn't around yet to put processes in unique scopes) and programmers were stuck with finding short, yet unique, names. Suppose you just wrote a program to scan the Wikipedia reference desk for unsigned comments and then sign them. What would you call it if you were limited to 8 letters? How about wrducbot? -- kainaw™ 13:23, 17 December 2007 (UTC)

Hehehe! That's pretty funny. Your idea of life in the computing stone age is a little too recent! In the stone age, the nearest thing we had to a cross-platform operating system was UNIX. Back in the mid 1970's it had a 14 character limit (because you had 16 byte directory entries with 14 bytes of filename and 2 bytes of inode number) - but by the late 1970's UNIX gave you arbitary length filenames that could contain any characters except '/' and '\0'. Then (in the early bronze age) came CP/M with it's crappy 8.3 alphanumerics-only (kinda) limit - then (in the iron age) PC-DOS and eventually, MS-DOS which were initially both CP/M compliant and contained the same limits as it did, but with slightly more lenience about what characters you could put into the filename. So, no originally, file names could be much longer, 8.3 filenames were a temporary aberration courtesy of "Digital Research Corp". However, I'm not sure that the OP is asking about the file names - I think we're being asked about the names you hear them referred to in discussion about viruses - which might happen to be the same as the filename - but not alway so. SteveBaker (talk) 16:56, 17 December 2007 (UTC)

Also worth noting is the fact that under Unix, the system calls dealing with filenames all passed general-purpose strings back and forth, such that when filenames were expanded from 14 characters to arbitrary-length, most application code didn't even need recompiling, let alone rewriting. Under MS-DOS, on the other hand, many of the key interrupts (i.e. system calls) used a rigid data structure which could hold exactly 8.3 characters and no more. So even when that platform was dragged kicking and screaming into the arbitrary-length-filename modern age, for quite a few years every file needed two names, an arbitrary-length one and a backwards-compatible 8.3 one, for the benefit of all the extant programs that still used the old interrupts.

(In fairness, Unix had a small version of this problem, in that under V7 and 2.8bsd Unix, there was initially no readdir library, so some programs rolled their own 16-byte-directory-entry-readers, and did need to be upgraded when readdir and arbitrary-length filenames came along.) —Steve Summit (talk) 03:17, 18 December 2007 (UTC)

Also be aware that many virus programmers are from all over the world. "Zlob", for example, means "wickedness" or "malice" in Slovenian (which might be a coincidence, but I'm just pointing out that seemingly meaningless words might not be so meaningless). --24.147.86.187 (talk) 15:28, 17 December 2007 (UTC)

Music file editing

Hi, I have a CD which contains a recording of some music performed by friends. It’s currently in MP3 format and I’m useing Vista on my computer. The problem is I have about 30 seconds of banging chairs and laughter ect. at the start and end of the clip. Is there some share ware that I could download that I can use to “lop off” these sections of the recording? Failing that, what software could I buy that will do this? Thanks, --S.dedalus (talk) 07:55, 17 December 2007 (UTC)

Audacity will do that. It's cross-platform and free. There are other options at List of free audio software. --Kateshortforbob 10:00, 17 December 2007 (UTC)

Don't use Audacity, since that would be destructive. You want to directly cut the file instead of decoding, editing, then re-encoding it. This is called transcoding and you should avoid it if at all possible.

What you need is something to directly cut the MP3 files. You can try searching for "mp3 direct cut". Lots more info at http://hydrogenaudio.org --Kjoonlee 20:18, 18 December 2007 (UTC)

Whilst you are correct about avoiding the repeated decoding and re-encoding of MP3's, it may not be possible to avoid doing it once. True, if the only thing you ever want to do to it is crop the junk off of the ends - then, by all means seek a solution to doing that without transcoding - but if you ALSO want to do other processing (noise reduction, fade in/out, bass/treble boost, whatever) then you'll have to transcode anyway. The trick in that case is to ONLY do it once. So load the track into Audacity, save it out in something without compression (WAV for example), do all of your processing - then do a one-time conversion back into MP3 when you're completely done. If you plan to write it out to a CD-Audio disk then you don't suffer any penalty at all because the recording software has to decode the MP3 anyway - so you might as well do that yourself and hand the CD-Audio recorder a WAV file instead of an MP3. SteveBaker (talk) 20:53, 18 December 2007 (UTC)

Well, if all you want to do is fade out, you can adjust the amplitude on a frame-by-frame basis without reencoding. I think at least some of the more advanced "direct cut" programs support this. --Kjoonlee 22:05, 18 December 2007 (UTC)

mediacoder

I'm trying to recode FLVs into AVIs but all it does is make them into 1 second movies. Can anyone help me figure out what I'm doing wrong? —Preceding unsigned comment added by 206.169.187.67 (talk) 08:01, 17 December 2007 (UTC)

Get MediaCoder PSP Edition, its freeware, legal, and encodes everything fully.

This might be what you're using, I don't know, but I know that it encodes FLV's to AVI's

What are you using to play the AVI's btw, cuz this might not work for it? 75.23.79.10 (talk) 21:32, 19 December 2007 (UTC)

Real Player. It plays AVI's. When I recode them (I do use mediacoder by the way), the properties state that the movie is only 1 second long, but the flv's are around 5 minutes. —Preceding unsigned comment added by 63.193.9.8 (talk) 20:12, 20 December 2007 (UTC)

Making a digital disk of jpeg pics and background music.

I bought a new Dell PC last year with which I am very happy. I am not a techie but I do a lot of digital photography and I copy music onto the PC too. All I want to do is send friends and family a disk with family and scenic pictures on it, with background music they can listen to whilst watching the pics. But although I can copy music OR pics onto a CD-R disk with no problem, and whilst I can copy zillions of pics onto a DVD-R disk no problem, whenever I try to copy music to the latter I get a message from my Roxio "Burn CDs and DVDs" centre telling me that the DVD-R disk I am trying to write music to is not capable of having music copied to it. And every time I ask a sales person why not all I hear is a lot of "white noise" from them. It seems there is so much confusion out there that I have resorted to ask the question here ie please, what disk should I use, and how do I go about copying both my jpegs and music onto it? Many thanks for reading this and hopefully responding in due course. Thanks 81.145.240.102 (talk) 20:56, 17 December 2007 (UTC)

OK - first of all, dumping a bunch of music files and '.jpg' image files onto a DVD will NOT result in something they can just stuff into their DVD player and hear your music playing while they watch the pictures. To make that happen, you have to make a movie from the images and the music - which is going to require some specialised software.

Presuming you understand that - but you really did want to just put some music and some images onto the DVD so that each one can be read on a computer by clicking on it - then there should be no problem with copying '.mp3' music files onto the DVD along with the '.jpg' images - they are all just files. What's probably happening is that you are trying to write music to the DVD as if it were a compact disk audio disk (the kind you could play in a portable CD player for example). If so, this is by no means an easy matter - mixing CD audio and data files on the same DVD disk is really hard to do.

So, if your intent is to give your family a DVD with a slide show with music playing over the top of it, you'll need some kind of a movie making program...you didn't tell us whether you're using Linux or Windows - so I'm going to guess the latter - and because of that, I'd better defer to someone else to answer the question: "What is the best movie making software that can be had for $0 that lets me make slideshows?"

SteveBaker (talk) 21:57, 17 December 2007 (UTC)

Windows Movie Maker, adequete for this use. --antilived^{T | C | G} 03:30, 18 December 2007 (UTC)

Thanks both. I did find I had Windows Movie Maker on my PC and I succeeded in making a movie of jpegs and music that I copied to both a CD-R and a DVD-R, both of which played back magnificently on my PC - but neither of which will play back on my DVD player - I keep getting a message saying 'Invalid Input'. Any suggestions or criticisms welcome. Thanks again. 81.145.240.102 (talk) 11:53, 18 December 2007 (UTC)

If you simply copied an AVI file to the discs, then that does not create something that is readable by a DVD player. You need to use an authoring tool, as briefly described in the Windows Movie Maker article. It would help to know the version of Windows you have, as well as the version of WMM. --LarryMac | Talk 17:15, 18 December 2007 (UTC)

I'm fairly certain there's a PowerToy to handle this dilemma. I'll give it a look and give you a link if I can. RockMaster-talk|contribs 03:24, 19 December 2007 (UTC)

Windows XP - and Windows MM Properties say -Version 5.1 (Build 2600.xsp2.qfe.070227-2300. Service Pack 2) AND ALSO Windows MM Version 2.1.4026.0. Thanks for your help - sorry for causing so much trouble. 81.145.241.150 (talk) 19:27, 18 December 2007 (UTC)

I have a DVD recorder that I use to record things off TV. To be able to play DVD-R (or DVD-RW) disks elsewhere, I must finalise the disk. Maybe, Windows Movie Maker has the same feature; so could that be the cause of your problem? Astronaut (talk) 03:26, 19 December 2007 (UTC)