Wikipedia:Reference desk/Archives/Computing/2007 December 16

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

December 16

Need to read my Mac OS 9 cdrom on a Windows XP computer

I have a Mac OS 9 cdrom and there was some things I wanted to grab off of it. Problem is that I'm using Windows XP and putting the disk in doesn't do anything.

Can anyone suggest something? —Preceding unsigned comment added by 64.252.187.82 (talk) 04:50, 16 December 2007 (UTC)

If they are programs that you wish to use, you cannot transport things written for Mac OS9 to a Windows computer; it will do you know good to try to run them. If they are documents, then you will have to find a Apple computer (OS X/Leopard will suffice), grab it from the CDROM, and email it to yourself. Occasionally, the files will still not rener correctly on PCs, as Finder had a weird format for documents. However, this usually won't happen; if it does, you can try back here again (there are ways of decoding the files). The Evil Spartan (talk) 05:44, 16 December 2007 (UTC)

If I recall, there was some wallpaper on the CD along with a few video clips that I wanted to check out. My Mac is no longer being used at the moment, but I do have access to a computer running a Linux distro. Can I mount the CD that way? Thanks for your reply. 64.252.187.82 (talk) 06:13, 16 December 2007 (UTC)

You might need something that can read HFS+. --Spoon! (talk) 12:33, 16 December 2007 (UTC)

Try MacDrive7 for PCs... http://www.mediafour.com/products/macdrive/ --66.136.247.203 (talk) 06:30, 20 December 2007 (UTC)

zapgrab not working properly

I have zapgrab (freeware screen capture utility)on a computer at work and one at home and it works fine on those and I think it's great.

I have a new, second computer at home (Windows Vista OS, if that matters). Unfortunately Zapgrab doesn't seem to work properly on it. What happens is I click grab and make a box around the item, I notice that the box is opaque white (on other computers it doesn't obscure the items I'm trying to grab). When I paste into an application like PowerPoint or Word or anything else, I end up with a black box instead of the image.

I've downloaded and redownloaded (http://www.zapgrab.net/) zapgrab several times in an effort to get it to work. I've googled it and I'm starting to think I'm the only person who has ever had any problem with it.

Please help. —Preceding unsigned comment added by 141.154.53.28 (talk) 04:10, 16 December 2007 (UTC)

I think Vista's graphics system works differently due to their use of translucency etc. Have you tried turning off Aero? —Random832 16:04, 19 December 2007 (UTC)

Thanks for the reply. I've since realized that if I kill the process DWM.EXE that zapgrab will work. How do I turn Aero off?

I don't know if is too late for this comment but I had the same issue running ZAPgrap on vista. It was happening because a compatibility issue. This workaround worked for me: 1. Right click on ZAPGrap properties. 2. Compatibility Tab. 3. check mark Disable desktop composition.

That's it. Everytime you run ZAPgrap the color scheme will be temporarily change to Vista Basic. This change will not affect the quality of the captures. I hope this help you.

telephone receiver symbol in MS Word

Hello, I want to insert a small symbol(?) or image of telephone receiver in my letter head against my telephone numbers. Now I have <tel.*******> in my letterhead. I want to replace those three initial letters of the word 'telephone' with a telltale symbol. I have seen it done by others. But I can't find that symbol in Word. Can somebody help me? Dhwaga —Preceding unsigned comment added by Dhwaga (talk • contribs) 05:40, 16 December 2007 (UTC)

"Insert | Symbol" Font=Wingdings. In Word2003 it is on the top row. -- SGBailey (talk) 06:16, 16 December 2007 (UTC)

Unicode also has some telephone signs, such as ☎ and ✆. ›mysid (☎∆) 09:20, 16 December 2007 (UTC)

Sony NWZ-S616F mp3 player

When will the Sony NWZ-S616F 4GB Walkman MP3 Player be available in Australia? --Candy-Panda (talk) 07:56, 16 December 2007 (UTC)

Not being able to see the progress of some downloads, why?

How don't some servers let you see the progress of a download? How do they do it? All you can see is a blue rectangle sliding from left to right repeatedly in the progress bar. --Taraborn (talk) 10:00, 16 December 2007 (UTC)

They simply do not report the size of the object you're downloading. --antilived^{T | C | G} 10:20, 16 December 2007 (UTC)

Oh, okay, didn't know that. I thought that it would be the other way round: that they actively did something to hide the size of the file. --Taraborn (talk) 10:22, 16 December 2007 (UTC)

When a server sends a file to the browser, it has to enter in an HTTP header that tells it what kind of file it is (so the browser will know what to do with it—open it as an HTML page, open it as a movie in the browser, download it to the hard drive, etc.). One of the fields in the HTTP header is the size of the file to be downloaded. If that isn't filled in, then the browser has no idea how big the file it is downloading will be, and so can't estimate how much of the file it has left to download. The HTTP header of a generic file to be downloaded might look like this:

     Content-type: application/x-download
     Content-Length: <file size>
     Content-Disposition: attachment; filename=<name of file when downloaded>
     Content-Transfer-Encoding: binary

That would tell the browser, "I'm going to send you a bunch of binary information, of exact <file size> length, and you should download it (don't try to open it in the browser!) into a file named <name of file>. Here it comes!" --24.147.86.187 (talk) 15:06, 16 December 2007 (UTC)

AVI to RMVB

Hello all, I've been trying to find a program that converts avi to rmvb, but all I seem to find are demos. Can anybody tell me the name or a link to download a free complete converter? Also I know that RMVB files are smaller, does that affect the quality of converted avi? Thanks. —Preceding unsigned comment added by 41.232.118.116 (talk) 13:36, 16 December 2007 (UTC)

Suggest look into MPLAYER. It's free. Also it's command line driven (but there may be a GUI front end as an add on-not sure). It doesn't know RMVB by default, but I googled for mplayer+rmvb and found this discussion that links to dll for using rmvb. http://www.moviecodec.com/topics/805p1.html

When converting any lossy media, you often lose some quality. Mplayer will give you full control over compression values. You may have to experiment for best results. —Preceding unsigned comment added by 66.92.130.188 (talk) 22:01, 17 December 2007 (UTC)

Windows explorer error

I use windows XP and sometimes this error message [1] appears when I try to open folders that contains things I copied from DVDs or the camera. On clicking the "Close message" button, it closes all open folders at that time. Any ideas on how to stop this? —Preceding unsigned comment added by Neemsay (talk • contribs) 14:00, 16 December 2007 (UTC)

Try this:

1. Right-click on My Computer
2. Click Properties
3. Open Advanced
4. Click Settings under Performance
5. Open Data Execution Prevention
6. Select the first option.
7. OK, OK, OK...

--grawity ^{talk / PGP} 15:04, 16 December 2007 (UTC)

I found it is already set to the first option :s any other suggestions? —Preceding unsigned comment added by Neemsay (talk • contribs) 16:49, 16 December 2007 (UTC)

Virus scan? Explorer is trying to access something that's off-limits to it, like another program or something in driver/kernel space. Could be malicious --ffroth 03:32, 17 December 2007 (UTC)

I scanned these folders but nothing came up. Why should that folder be considered off limits anyway? it just contains things I copied from a DVD ! —Preceding unsigned comment added by Neemsay (talk • contribs) 08:48, 17 December 2007 (UTC)

(Windows XP Pro, SP2) PIDs over 28000

I'm just wondering if it's normal for processes on a WinXP (Pro, SP2) system have PIDs over 28000 (right now the largest is 28648). I disabled Fast User Switching yesterday, and today (after my sister logged out and I logged in) noticed that the PIDs (in Task Manager) are unusually big. Is this normal? --grawity ^{talk / PGP} 15:04, 16 December 2007 (UTC)

Open-source alternative to .NET

Is there a completely open-source development framework with capabilities similar to those of Microsoft's .NET and the associated languages? I am not asking about implementations of .NET itself, such as Mono (software), which is considered by some to be "dangerous to depend on" due to patent issues. Thanks. -- Meni Rosenfeld (talk) 15:13, 16 December 2007 (UTC)

It rather depends on what capabilities in particular you care about. If you want a dynamically-compiled object-oriented language with automatic memory management and a pretty comprehensive runtime library, i.e C#, then OpenJDK may be what you want. If you want a single runtime system on which you can run programs written in a variety of programming languages then OpenJDK may also be for you (in addition to Java you can run JRuby, and some dialects of Scheme and Lisp); more generally the Parrot virtual machine (originally developed for Perl 6) can host a wide variety of languages (albeit with varying degrees of maturity). And of course, if you truly want "runs everywhere, library for everything", there's always C. -- Finlay McWalter | Talk 15:30, 16 December 2007 (UTC)

...and if you want a pretty efficient pure-functional programming language (which may suit a mathematical brain better than the aforementioned), with a reasonable set of libraries, then there's Haskell. Or Scala on OpenJDK. -- Finlay McWalter | Talk 15:35, 16 December 2007 (UTC)

Thanks, I'll look into those. I'll also focus my goal a bit, in case there is more to be suggested. As far as the language goes, C# is indeed what I had in mind (though I come from a VB background). Among the languages you have mentioned, I'd say Java is closest to it; But I have the impression that C# is more "advanced" and "powerful" than Java. Is there, then, anything more reminiscent of C#? As for libraries, it should be as easy as possible to create applications with a Windows-like GUI, other than that - the more powerful and easy to navigate, the better. Also important is the availability of a powerful IDE, a la Visual Studio. You've mentioned C - it is probably too "hard-core" for me. -- Meni Rosenfeld (talk) 16:42, 16 December 2007 (UTC)

C# really is a pretty close copy of Java, with a few improvements and a few more "improvements". Bar the differences in the libraries (C#'s is mostly the Windows API with wrappers, Java's its own largely-platform-independent library) the two languages are exceedingly similar. GUIs are straightforward in Java (and in fairness, in Python, Perl, Ruby, and a dozen others too). As for IDEs Eclipse and NetBeans are popular and powerful, and support many languages, including all of the above. -- Finlay McWalter | Talk 16:54, 16 December 2007 (UTC)

Okay, thanks. -- Meni Rosenfeld (talk) 17:00, 16 December 2007 (UTC)

• Let's be honest here. The only reason C# exists is because Microsoft found itself unable to control Java. C# does indeed have a few minor improvements over Java, but the idea that the very minor differences are going to make or break your ability to write a high-quality system is nonsense. Programmers put people on the moon with assembler. If you want something like C#, but are wary of Microsoft's historical treatment of its developer base, you can go with Java without a second thought. --Sean 23:11, 16 December 2007 (UTC)

SQL Server Service Manager?

What does the SQL Server Service Manager do? I have it in my system tray but it's never "connected" as far as I know, and it takes some serious system resources. Can I safely exit it?

Thanks in advance,

Perfect Proposal ^{Speak out loud!} 16:19, 16 December 2007 (UTC)

Basically, the SQL Server Service Manager provides an interface to any instances of the SQL Server database management system that may be running on your system. As for whether it's connected - if the icon in the tray includes a green arrow in a white circle, then it more than likely is connected to at least one instance. And as for shutting it down - that's a whole different ballgame, because there are quite a few applications out there that use SQL Server as their data store, and shutting it down may prevent these from working properly (some even have a scaled-down version of the SQL Server DBMS embedded in them).

I would suggest that if it's your work machine, consult the IT department. If it's your home machine and you know you're not running any seriously heavy software, you may be safe enough to close it - try pausing it for a session or two and see what happens (you can always start it up again, if something starts acting funny)Gabhala (talk) 18:30, 18 December 2007 (UTC)

Measuring Angles of a Triangle

Hello. I am making a program that can calculate angles of a triangle given its three side lengths. In the Turing (programming language), I can calculate the cosine/sine value of a degree. How can I calculate the degree given a cosine/sine value (i.e. reverse the cosd/sind predefined function)? Thanks in advance. --Mayfare (talk) 16:26, 16 December 2007 (UTC)

Just in case there is no language feature to do that, I will provide a mathematical answer which might be useful: For a given value $y$, set $x:=0$ and repeatedly calculate $x:=x-{\frac {\sin x-y}{\cos x}}$ until the result no longer changes. Then x will be the value (in radians) satisfying $\sin x=y$, which you can easily convert to degrees. The calculation for inverse cosine is similar. -- Meni Rosenfeld (talk) 16:49, 16 December 2007 (UTC)

• This page lists various compositions of basic math functions. --Sean 23:40, 16 December 2007 (UTC)

It appears that there are arctan and sqrt functions in the language. From the link above, you should be able to compute arcsin and arccos. Then you can convert from radian to degree if you want. --Spoon! (talk) 04:17, 17 December 2007 (UTC)

I got it! It was arccosine. Thanks to everyone. --Mayfare (talk) 21:45, 17 December 2007 (UTC)

Is it possible to open and edit a MS Outlook msg file?

Is it possible to open and edit a MS Outlook msg file? If so how easy is it to do? (Should msg be regarded as reliable evidence?) —Preceding unsigned comment added by 79.74.84.54 (talk) 17:34, 16 December 2007 (UTC)

It looks pretty easy to me; the message body seems to be stored in the clear. But I don't have one handy to test. As for "reliable evidence", it is always evidence of what, but assuming you mean evidence as to the veracity of an e-mail, to my knowledge there is really no way to ever guarantee reliable e-mail evidence. At best you could maybe get the e-mail server to affirm that a given e-mail passed through it but even then there are other issues involved (if their SMTP isn't authenticated, for example, anyone could send the e-mail posing as anyone else, and all of this assumes any accounts have not been compromised). I'm not sure how the courts treat e-mail messages but they are a pretty insecure message format in most cases as they are almost always sent and saved in the clear and without much by ways of guaranteeing that the person who it says has sent it actually sent it. --24.147.86.187 (talk) 17:43, 16 December 2007 (UTC)

If the questioner means "How easy is it to tamper with an MSG file?", the answer is "Trivially". Just open MS Outlook, drag the file from the desktop into the Outlook Inbox, open the message, click "Edit Message", type whatever you like, close the message, then drag it back to the desktop. Job done! --Heron (talk) 19:24, 17 December 2007 (UTC)

PC game suggestions

This is a rather spurious and unimportant question, but my guess is whoever is monitoring this board will have some suggestions. I'm looking to buy Christmas presents for a group of friends, and thought that an online pc game would be a cool way for everyone to game together. Any suggestions on an older pc game with an online mode? I'm not necessarily talking mmo, just allowing players of the game some multiplayer or coop over the internet. I'm looking in the $10 to $25 price range, but finding something that is old enough to be that cheap, online and any good is proving to be more of a task than I thought. Thanks for any advice in advance! Newsboy85 (talk) 19:33, 16 December 2007 (UTC)

Worms Armageddon! It's so much more realistic in 2D... --Seans Potato Business 23:40, 16 December 2007 (UTC)

Doom is THE way to go. Is there anything more satisfying than turning your friends into pixelated meatloaf with a rocket launcher? I think not. 216.178.51.214 (talk) 04:28, 17 December 2007 (UTC)

Team Fortress 2 is fun if you've got enough friends to form two teams, and they're comfortable with FPS games. Otherwise I like Seans's suggestion. 72.10.110.107 (talk) 15:37, 17 December 2007 (UTC)

StarCraft is a classic, and even still played a lot, even over nine years after it's initial release. This (as well as any other good RTS game) might draw some more long-term gameplay than a standard FPS, depending on the preferences of your friends. At least with me, FPS games haven't endured time as well as RTS games have. —Akrabbim^talk 18:48, 18 December 2007 (UTC)

I like Rise of Nations - it's not too old, but it runs well on old PCs, is easy to LAN, is very deep with multiplayer options, easily modded, and is a lot of fun. -Wooty [Woot?] [Spam! Spam! Wonderful spam!] 05:14, 19 December 2007 (UTC)

Command and Conquer Red Alert 2 or DEFCON are both pretty fantastic. If you want something free then have a look at Soldat or Scorched 3D, both of which work great over and online. Worms World Party or Worms Armageddon are good too. If you prefer tactical games then the older Rainbow Six games (Raven Shield is the best in my opinion) are fantastic TheGreatZorko (talk) 13:31, 19 December 2007 (UTC)

Google searches

As powerful and as fast as Google is, why doesn't the search engine support partial word or case-sensitive searches? I'm sure this has been discussed by somebody, somewhere....--The Fat Man Who Never Came Back (talk) 20:31, 16 December 2007 (UTC)

I'd imagine that partial word is a lot more computationally intensive than whole words, depending on how they index things. I'd be surprised if case-sensitivity was hard, though. --24.147.86.187 (talk) 21:26, 16 December 2007 (UTC)

The problem is not that Google has to "search" for pages containing a partial word or a differently capitalised word - the problem is that Google also has to find the most relevent searches. That means that it has to search every page on the Internet to count how many links there are to every one of the possible candidate pages in order to figure out which out of the millions (or perhaps billions) of pages that match your search terms should be presented to you. Since it's quite utterly impossible for even Google's vast computer arrays to do that when you type in the terms, it has to have pre-computed for every possible search word which pages have the highest 'page rank'. It's a massive table of words versus URL's - but it would be incomparably more vast if it also had to have entries for partial words and alternative capitalisations. You can read PageRank to find more details - but the 'Cliff Notes' version is "They make that restriction for a very good reason." SteveBaker (talk) 04:27, 17 December 2007 (UTC)

I had to read your response (which was very good) a couple times before I understood, but I get it. You use the phrase "incomparably more vast"..... just how much more vast? 1 thousand times? A million times? A trillion times? Google has lots of money and lots of computers, couldn't they just build a bigger index? Perhaps they believe the added value would be trifling compared to the resources they'd have to invest. But I think the results would be pretty cool. For example, it would be useful to do searches to see whether a word that is capitalized/punctuated in a certain way has more hits than an alternative punctuation, etc.--The Fat Man Who Never Came Back (talk) 04:46, 17 December 2007 (UTC)

Well if they had a big table somewhere with every possible word they ever saw on a website (possibly a few million words) with the top-ranked sites for every word - then to increase the size of that table to include every possible PARTIAL word - and every possible CaPiTaLiZaTiOn of every word would require much more storage space. If you imagine a fairly typical six letter word like "search", you'd need to add s*, s*h, s*ch, s*rch, s*arch, se*, se*h,....etc....SEARCH, Search, SEarch,...etc...S*, S*h, S*H, S*CH, S*Ch, ...etc. It's not hard to imagine that there would be many hundreds of possibilities for just that one word. That would mean that the table would be many hundreds of times larger - and the time taken to build it would be many hundreds of times longer and the server computers that run Google (which use a 'distributed' table searching method) would need hundreds of times more processors and memory to do it. Basically, it would be REALLY bad news for Google share-holders - and might not get them any additional users or (more importantly) more advertisers. So why would they do this?

If they resorted to a blind search, they'd have to examine several trillion web pages (I think that's how many there are now) for instances of your phrase. This would probably tie up the whole of Google's massive computer farm for several seconds (which is how they can do this internally - but not offer it to the public) - and then sort the resulting hits (of which there may be millions) according to their page rank...which is something that one computer could do in a few minutes probably. So that's a method that they won't likely offer to the public anytime soon.

SteveBaker (talk) 22:10, 17 December 2007 (UTC)

I have heard that Google supports regular expressions (not sure if thats what you meant, but seems close enough) on their internal searches, so if you work there you can use them. The reason they don't do this for everyone is just what the first answer says, its just takes too much time to return a quick search. —Preceding unsigned comment added by 199.111.211.113 (talk) 05:24, 17 December 2007 (UTC)

Screenshots

How would I make a screenshot of my computer? DuncanHill (talk) 20:43, 16 December 2007 (UTC)

Seriously? PrintScreen then paste usually does the trick on a PC.--The Fat Man Who Never Came Back (talk) 20:56, 16 December 2007 (UTC)

Thanks! Someone was asking for one to help solve a display problem on wp, and it's something I've never needed to do before. DuncanHill (talk) 21:03, 16 December 2007 (UTC)

Well, I did that, but now I can't upload it because it is a .bmp and apparently Wikipedia doesn't want any .bmp files, whatever they are. When I was 13, my school had a new computer suite installed, but my year group weren't allowed to use it, as we were 1)"never going to need to use these things", and 2)"too old to learn it anyway". DuncanHill (talk) 21:19, 16 December 2007 (UTC)

Paste it into MS Paint and you should be able to save it as a PNG, I think. --24.147.86.187 (talk) 21:27, 16 December 2007 (UTC)

[ec] Try opening the file with Microsoft Paint (under Accessories) or a similar application. It will allow you to save the image as any one of a number of formats. (.bmp = bitmap, a file which explicitly specifies the color values for each pixel, as opposed to .jpg, which uses compression) -- Meni Rosenfeld (talk) 21:28, 16 December 2007 (UTC)

Right! I think I've done it now! (Didn't know I had MSPaint before this either!). DuncanHill (talk) 21:35, 16 December 2007 (UTC)

MSPaint wasn't in the accessories, don't rightly know where it was, found it through the search thingy. DuncanHill (talk) 21:43, 16 December 2007 (UTC)

o_o --ffroth 03:31, 17 December 2007 (UTC)

If I were you, I'd download a copy of GIMP - it's a WAY better program than MSPaint and it's free. It has an 'Acquire' button in the 'File' menu that can screen grab either the entire screen or just one window with a bazillion options. Once you've captured the image, you can save in '.png' (which is probably the best format for Wikipedia) - or any of a couple of dozen other formats. It's also a great paint/image-processing program - better than Photoshop IMHO. SteveBaker (talk) 04:21, 17 December 2007 (UTC)

How about screenshots for macs? —Preceding unsigned comment added by 63.193.9.8 (talk) 20:46, 17 December 2007 (UTC)

I'm pretty sure GIMP runs OK on the Mac - but it's possible you have a better 'native' solution available. Sadly I'm no Mac expert. SteveBaker (talk) 22:00, 17 December 2007 (UTC)

I read the GIMP article, then looked at their website, I have no idea what they are on about - tarballs? binaries for Windows?DuncanHill (talk) 03:12, 18 December 2007 (UTC)

Head over to the MacGimp project: http://www.macgimp.org/ - they speak fluent Apple there, you should be right at home. SteveBaker (talk) 03:48, 18 December 2007 (UTC)

I'm on Windows. DuncanHill (talk) 03:53, 18 December 2007 (UTC)

Sorry - I confused you with 63.193.9.8 who wanted Mac advice. There is a Windows installer for GIMP: http://gimp-win.sourceforge.net/ SteveBaker (talk) 18:02, 18 December 2007 (UTC)

Do you use Windows? If so, you want Gimp for Windows. Binaries are programs you can run on your computer. You download it and run it. It installs Gimp. You will want to find 3 or 4 "Gimp for the absolute beginner" lessons online (Google for some). Gimp has a very steep learning curve just to get started. After an hour or so of banging your head and trying to understand the introductory lessons, it will suddenly all make sense and become very easy. Then, you will probably use Gimp for all of your graphical work. -- kainaw™ 03:22, 18 December 2007 (UTC)

In case you've read "programs you can run on your computer" and wondered "what else is there?", the answer is source code from which the binaries are compiled. On Linux, it is common to download the source code of a program and compile it to a binary on your own system. -- Meni Rosenfeld (talk) 14:09, 18 December 2007 (UTC)

Thanks for all the info - I found a thing called GIMPShop, which is meant to be an easier to use version, will have a play with it. DuncanHill (talk) 14:26, 18 December 2007 (UTC)

GimpShop is Gimp with a PhotoShop-style interface. It is easier if and only if you already learned to use PhotoShop. As with Gimp, if you've never messed with layers you will have a very tough time just jumping into GimpShop (or PhotoShop or Gimp). -- kainaw™ 18:06, 18 December 2007 (UTC)

Accessories in WinXP

I just discovered MSPaint on my pc, but it wasn't listed in the "accessories" thingy accessed from the start box. What else is normally in the accessories? DuncanHill (talk) 21:49, 16 December 2007 (UTC)

If you're referring to XP, it is commonly Accessibility, Communications, Entertainment, System Tools (important), calculator, dos prompt, notepad, wordpad, explorer and of course paint. Sandman30s (talk) 23:00, 16 December 2007 (UTC)

Got all those and a few more too - was just a bit worried there might be something else obvious hiding away! DuncanHill (talk) 23:04, 16 December 2007 (UTC)

Another one is charmap.exe which has been around for more than a decade. Graeme Bartlett (talk) 06:05, 17 December 2007 (UTC)

Now that one wasn't there! And it's useful too, thanks. DuncanHill (talk) 03:18, 18 December 2007 (UTC)

Restricting login times on OS X

My brother seems to be wasting solid nights on the computer, and then as a result not going to school in the morning. I had set up our wireless router to simply block traffic between 11.30PM and 7AM, but that was unfair for other family members. Also, the times seemed to confuse the router - sometimes it would block during the day, or not at all. Recently, I've begun SSHing to our iMac and giving it something along the lines of "sudo shutdown -h 23:30", but he can obviously just switch it back on again. I've been thinking about setting up some sort of cronjob to automatically create a /etc/nologin file at 11.30PM and then delete it 7AM, but I have no idea whether it's even possible or not, let alone how to do it. Alternatively, could I create a cronjob to issue a shutdown command whenever the Mac is on between those times? I'd really appreciate any help or suggestions. Thanks :)--saxsux (talk) 23:51, 16 December 2007 (UTC)

• I dunno if OS X has normal cron jobs, but an entry like:

* 0-7 * * * shutdown -h now

would cause a standard Unix system to shutdown every minute it was up between midnight and 7am, which would presumably make it annoying enough for him to go find some other thing to do. That said, technical solutions to social problems are notoriously ineffective, so perhaps some good old fashioned parenting is in order? --Sean 00:31, 17 December 2007 (UTC)

Take the computer out of his room? DuncanHill (talk) 01:33, 17 December 2007 (UTC)

Or just take the keyboard and/or mouse. (Yes, you can operate OS X without a mouse, but it isn't easy.) --24.147.86.187 (talk) 02:19, 17 December 2007 (UTC)

This is not a laptop - right? You can buy gadgets that will turn off the power to the computer (or perhaps just to the monitor) at specified times. This one for example. The idea is that you plug the monitor power cord into this box - which has programmable timers and a physical key-lock that locks in the settings and prevents the monitor cable from being unplugged. Then this gadget plugs into the wall. When the timer says "Bedtime" - the monitor turns off. Some of them have countdown timers that give the kid 5 minutes and 1 minute warnings. Software solutions to this are possible - but I'm pretty sure a smart kid could get around any of them if determined enough. SteveBaker (talk) 04:16, 17 December 2007 (UTC)

But then you can just unplug the computer from that and plug it straight into the mains. I like the cron idea, you can't touch that unless you're root. --antilived^{T | C | G} 04:31, 17 December 2007 (UTC)

No - you can't unplug the monitor from the timer gizmo because the mains connector is trapped inside the locked box. Take a look at the link I provided - there is a diagram showing how it works. You can't subvert it unless you have a power cord that you can unplug at the monitor end of the cable AND a spare cable. The cron idea isn't bad...but I bet a smart kid could figure out a way around it. If you have physical access to a computer, there aint no such thing as security! (My son would probably: Boot Linux-for-Mac from a memory stick or a Live-CD, log in as root, mount the main drive, change the crontab file - reboot...done!). SteveBaker (talk) 17:12, 17 December 2007 (UTC)

This is all very lolly but you have to realize that without some corporal pushishment element it will be impossible to enforce. The power limiting that steve proposed is just stupid- you can completely switch out the power cable for another. Giving someone physical access to a machine and trying to keep them out of root is similarly laughable. Maybe you could do something to the circuit breaker to cut off his circuit every night, and lock that down, but only if you can be sure that he's not going to steal power from a neighbor or buy a few UPSes. Taking the keyboard/mouse might work. By far the best solution is to turn off his MAC address's internet access through the router after a certain time, and restrict connectivity by MAC address. If he knows how to change his MAC address though you can do nothing to keep him from finding out another computer's address. --ffroth 05:46, 17 December 2007 (UTC)

You are assuming the monitor has a replaceable power cord...many (most even) do not. The iMac has a weird power cord (http://www.welovemacs.com/9225035.html) - which costs $35 to replace. So immediately, the kid won't be able to circumvent the power cord lock-box/timer. If he can afford $35 for a new cable - then just plan on surprising him once or twice at 1am and confiscating his replacement power cord. He'll run out of money for buying replacement cords much faster than you'll run out of patience. Trust me, Froth and Antilived are wrong - those power cutoff units will work very well indeed. Using it to cut off the monitor power is a better idea than cutting it off to the main computer box because by shutting off the monitor, you don't have to worry that you're trashing the vital piece of homework assignment he just spent 3 hours typing in. SteveBaker (talk) 17:12, 17 December 2007 (UTC)

He can always cut out the lock box entirely and mend the broken part of the cord, using half of the lock-box cord and half of the monitor cord. You'll run out of money for buying replacement lock boxes much faster than he'll run out of patience. Unless you give him a good whooping every time he does it. --ffroth 04:50, 18 December 2007 (UTC)

This isn't a 'reversible' operation - so I think it's safe to assume that you'd notice if that had happened...and then your reaction is to sell his computer on eBay and give the money to the WikiMedia foundation. SteveBaker (talk) 17:57, 18 December 2007 (UTC)

The only thing weird about that power cable is that it's in apple's designer color scheme, otherwise it looks like a standard C5 connector, and I found prices as low as $3 on google. The older iMacs use a C13 connector, the same as almost all other desktop computers and monitors —Random832 15:56, 19 December 2007 (UTC)

If doing something on the Internet is the reason your brother is staying up, you may try setting up your router to block Internet access just for his computer's MAC address during certain times of the day. --64.236.170.228 (talk) 14:15, 17 December 2007 (UTC)

You're sure that Mac's don't have replaceable MAC addresses? Er, let me pretend to be a determined kid for a moment. Yep - it took me 18 seconds with Google to find http://slagheap.net/etherspoof/ ...trust me - physical security is the ONLY way. SteveBaker (talk) 17:12, 17 December 2007 (UTC)

Why not simply move his computer to a more "public" part of the house? Or the garage? --66.136.247.203 (talk) 06:28, 20 December 2007 (UTC)