Wikipedia:Reference desk/Archives/Computing/2008 March 13

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.

March 13

the purpose of binding a socket to an address

In standard unix programming, what is the purpose of binding a socket (via the bind(2) command) to an address? I can see why one needs to bind to a certain port, obviously it is to tell the socket to listen on that port, but why give the option of an address? --Iownatv (talk) 01:22, 13 March 2008 (UTC)

It is possible to have multiple addresses on a single computer. You need to be able to tell the computer which address to use. -- kainaw™ 01:29, 13 March 2008 (UTC)

what else than 127.0.0.1 would it be? the local loopback. I thought it was uncommon in code to know what one's own address is. —Preceding unsigned comment added by Iownatv (talk • contribs) 01:43, 13 March 2008 (UTC)

If you were using it as a server, you could use a different IP for each service: Web, FTP, SMTP, etc. If your network is divided into subnets, the you could assign an IP for each subnet. --— Gadget850 (Ed) ^talk - 01:54, 13 March 2008 (UTC)

(ec) You appear to be thinking along the lines of desktop computers. I work primarily with servers. Two quick examples of multiple IP address uses:

• Server has a network connection to the world with an IP address of something like 11.22.33.44. There is a mirror server sitting right by it that the main program copies all changes to. The mirror is connected on a separate network connection with a fake address like 192.168.0.1. The program handles real-world activity on, say port 123 address 11.22.33.44. It talks to the mirror on, say, port 777 address 192.168.0.1.
• You have three websites on one server. Each requires SSL. Since the SSL handshake takes place before the hostname requested is given, you have to give the server three IP addresses. Each one requires a unique certificate for SSL. So, you listen on port 443 address 11.22.33.1, port 443 address 11.22.33.2, and port 443 address 11.22.33.3. Since you can uniquely identify which address is hit, you know which certificate to use.

There are many other reasons to use multiple IP addresses on a single server. I'm sure you can quickly think of a few. -- kainaw™ 01:56, 13 March 2008 (UTC)

To bind to all interfaces, 0.0.0.0 is used. (I think.) --grawity ^{talk / PGP} 15:46, 13 March 2008 (UTC)

Is it possible to lease multiple IPs from a DHCP server (on the same NIC)? :D\=< (talk) 03:55, 16 March 2008 (UTC)

TI-BASIC semicircle

Does anyone know how to draw a half-circle using TI-Basic? —Preceding unsigned comment added by 68.108.249.191 (talk) 02:04, 13 March 2008 (UTC)

Well, figure out whatever command it is to plot points and you could easily write a Midpoint circle algorithm function that would do it. --98.217.18.109 (talk) 02:08, 13 March 2008 (UTC)

Or not- it's a graphing calculator just graph the equation- it's going to be a lot faster than plotting individual points in BASIC. Use uhh strtoeq I think, something like that to convert "sqrt(1-x^2)" and store it in Y1, then turn Y1 on if it isn't already and then put one of the zoom commands to flush it :D\=< (talk) 02:17, 13 March 2008 (UTC)

strtoeq? —Preceding unsigned comment added by 68.108.249.191 (talk) 02:29, 13 March 2008 (UTC)

I'll check.. ok check the catalog for String>Eq( :D\=< (talk) 03:35, 13 March 2008 (UTC)

Can you give me specific steps? It gives back an argument error. --hello, i'm a member | talk to me! 04:14, 13 March 2008 (UTC)

You need to write the equivalent of:

x=x value of centre of circle !insert a value here

y=y value of centre of circle !insert a value here

a=angle that semicircle will make to the horizontal !insert a value here

r=radius of circle !insert a value here

For n=0 to pi step (1/(2 x pi x r) !use radians or change pi to 180 if you are using degrees

plot {x + r cos (n+a) , y+ r x sin (n+a)} ! plot each point

next n  ! repeat for all the points

stop

If you don't have a for/next loop use an 'if' statement and a loop

It should be easy for you to convert this to TI-84 syntax

If you can do that it would be interesting to look at Midpoint circle algorithm which is almost always a faster way to do it..87.102.8.240 (talk) 10:18, 13 March 2008 (UTC)

Why are you trying to plot points?! O_O Just:

String>Eq("sqrt(1 - x^2)") -> Y1
ZoomSquare

Note that String>Eq( is a token and so is sqrt( and so is ^2 (the 'squared' key) and so is -> (the STO key) :D\=< (talk) 13:25, 13 March 2008 (UTC)

Using my method I could plot semicircles at any angle, upside down, side ways etc..

PS I'm sure the equation is sqrt(1-x^2) or sqrt(r^2-x^2) for radius r. For x>1 (or x>r second case) there's a possibility of an error code if the computer doesn't like being given complex numbers.. I don't know how good TI are in this respect - so it may not be a problem.87.102.35.142 (talk) 13:40, 13 March 2008 (UTC)

Yeh you're right I changed it :D\=< (talk) 14:02, 13 March 2008 (UTC)

Also another one near the top - changed it for you.83.100.138.116 (talk) 14:40, 13 March 2008 (UTC)

SMS Gateways: How can I send an SMS text message via email to a Korean cell phone?

In the US, almost all cellular service providers have an e-mail address associated to each cell phone to send text messages to the phone via e-mail (e.g., number@messaging.sprintpcs.com for Sprint, number@txt.att.net for AT&T, etc.). How can I do the same with Korean cell phone companies (SK, KT, LG)? I haven't found much information about Korean cell phone SMS gateways. I would rather use the actual telecom if possible, rather than a third party service, to avoid number harvesting. —Preceding unsigned comment added by 66.75.102.95 (talk) 03:05, 13 March 2008 (UTC)

Wow that would be quite a useful feature, are the txts sent through email free to receive? From your description it seems like that the company merely sends the content of the email through SMS to your phone so as long as the phone is compatible to SMS I don't see what's the difference between a Korean cell phone to other cell phones. --antilived^{T | C | G} 05:16, 13 March 2008 (UTC)

With Sprint, in the US, e-mailed texts cost the same to send/receive as any domestic texts. It is really great, however, when sending international texts. Instead of being routed through the phone company's private networks, and being subject to international text fees, they are sent over the public internet as e-mail, so they just cost the same as a regular domestic text. The problem (which I'm trying to solve) is figuring out what the SMS gateways are for Korean mobile telecoms. I found that SK has a data service called NATE which may be in charge of their SMS gateways (if they even have any), since I've found a few Google results with the number@vmms.nate.com syntax. However, sending texts to a few friends using SK in Korea gets me an SMTP delivery failed response when sending from both my phone and my e-mail client on the computer. Unfortunately, I can't read Hangul, so I can't go through the nate.com site, which is all in Korean, to see if they have any support pages that could give me some more information. :( 66.75.102.95 (talk) 16:09, 13 March 2008 (UTC)

"Upgrade" to XP Pro?

Honestly, I should know this but I've been a little stumped with it recently. I recently (Christmas time) received a new Gateway P-6301 with Windows Vista Home Premium pre-installed on it. The computer's hardware is all still factory, with the exceptions of a few scratches. Heh. Anyway, without having to go through 10 acts of Congress could someone please tell me if there's a fairly simple and hassle-free way to upgrade to Windows XP Pro from pre-installed Vista? crassic!^[talk] 04:48, 13 March 2008 (UTC)

Do you have a copy of Windows XP Pro? If so, I don't think there should be a problem at all - just install XP as usual and format the drive. If you are asking about getting an XP license cheaper based on your current Vista - I don't know, but a quick search at Microsoft's site (for some reason they call moving from Vista to XP "downgrading") reveals some seemingly relevant results. -- Meni Rosenfeld (talk) 11:07, 13 March 2008 (UTC)

I technically don't own a copy, but I have a copiedLEGAL! disc with a good key. When I insert the disc, the option for installation is shaded over. And booting from the CD (as it doesn't want to work otherwise), I attempted to install but, of course, it just effectively ruined my current OS by removing NTLDR (and likely other key files.) crassic!^[talk] 01:43, 14 March 2008 (UTC)

Yeah you're supposed to boot from the disk .. :D\=< (talk) 03:59, 14 March 2008 (UTC)

The trouble with that (just installing XP as usual) is that it consumes a licence (so you've paid for Vista, and paid for XP, but are only using one). As the Vista licence Crassic has is a Gateway OEM licence, he should approach Gateway and enquire about their Vista->XP migration options. Microsoft does allow OEMs to offer this capability (and I think provides them with some tools to that end), although they don't exactly shout it from the rooftops. I'd also check that they'll allow a return to Vista at some future time when Vista is actually finished. The other programmes I've seen (I don't know anything about Gateway's) allow you do all this on one licence without any (financial) cost. -- Finlay McWalter | Talk 11:53, 13 March 2008 (UTC)

Vista's perfectly fine if your computer doesn't suck- yours unfortunately does. What's with all the vista bashing? You're not hard or something if you stay with XP (after all, it's all Windows garbage)- XP is stable but sorely out-of-date, which is painfully obvious every time I have to work with it. Vista's a memory hog but it's a far more mature OS than 7-year-old XP. Or switch to linux and dual boot XP for gaming- for its lower memory overhead. :D\=< (talk) 13:20, 13 March 2008 (UTC)

You would want to make sure that XP drivers are available for all of the hardware in your Gateway, which I understand can be an issue. --LarryMac | Talk 13:19, 13 March 2008 (UTC)

Yah, I've seen a lot of Vista gateway laptops that have no device drivers for XP. You'll have a 800x600 screen, no networking. :D\=< (talk) 13:22, 13 March 2008 (UTC)

My computer isn't really terrible, I honestly just believe Vista is too much of a hassle to deal with currently with all of the bugs. And having to reinstall often isn't much fun, since I've heard a few of my friends have had to do it as well. crassic!^[talk] 01:43, 14 March 2008 (UTC)

Vista isn't actually a memory hog, and I wish people would stop calling it that. It uses about 50mb more than XP SP2, with only its services running. The rest that you see in the task manager is something called Superfetch which means Vista puts programs it thinks you might use in the RAM so they launch faster. If another program requires that memory then the Superfetch cache is emptied, and the other program is allowed to use it as normal.

However Vista runs a lot better on 2GB of memory than the 1GB that you have (It still runs fine on 1GB of memory so I'm not sure why you want to switch). You could probably buy another 1GB stick of laptop memory for less than the price of a copy of XP Pro. TheGreatZorko (talk) 13:50, 13 March 2008 (UTC)

I wasn't talking about commit charge I meant specifically dwm.exe. I do run vista and compiz fusion and I have the memory for it, but compositing window managers like them suck. you. dry. :D\=< (talk) 13:59, 13 March 2008 (UTC)

DWM.exe often sits around at 30-50MB, which is hardly sucking all my memory, if that's what you are implying. Oh and turning off Aero gives you almost no speed boost by the way (because it's all done on the graphics card, and is turned off or frozen when a 3d application (or something that demands the use of the graphics card) has focus), so if you can run it you may as well keep it. TheGreatZorko (talk) 14:19, 13 March 2008 (UTC)

My computer is an Athlon FX-60 2.6GHz Dual Core, 3GB RAM, 1.1TB HDD, 8800GTX 768MB video card, so I would call it a gaming machine. And you want to know what OS I'm running? Windows XP Pro. I recommend the upgrade from Vista to XP. You can buy a XP install disc at tigerdirect.com or newegg.com and you should be good to go. Useight (talk) 16:40, 13 March 2008 (UTC)

Why don't you like Vista? Nvidia driver support is finally ok on vista.. :D\=< (talk) 16:46, 13 March 2008 (UTC)

Many reasons. Memory hog (even if that is just RAM being loaded with programs it thinks I might open (I'll open it when I want it)), slower boot time, annoying "Are you sure?" messages, the start button is now a circle that doesn't say start, driver incompatibility, takes up more hard drive space. Useight (talk) 02:08, 14 March 2008 (UTC)

Come on, think about it. Intelligent caching is exactly what you want. Firefox is already loaded in my memory even when it's not open. If I need to run firefox, it loads pretty much instantly. If I need to run anything else, that just writes completely over the cached memory. It's that simple- that memory just gets wiped immediately if you need it for anything else. So while it looks like you only have 5% memory free, half of your memory is actually superfetch and is released the instant you need it. Disable UAC (just don't run untrusted code; UAC isn't going to protect you from something malicious) to turn off the annyoing popups, disable unnecessary services just like you would in XP to speed up your boot/shutdown. Driver incompatibility isn't an issue anymore unless you're trying to downgrade to XP, in which case you have to check for driver compatability. You're right about hard drive space. :D\=< (talk) 03:08, 14 March 2008 (UTC)

Note: My computer isn't actually that terrible, though it is factory. 160 GB hard drive (250 GB external), dual 1.46 GHz processor (533 MHz FSB) with 1 MB level-2 cache, 1 GB DDR2 memory. The only thing I dislike about it is the video card, Intel should stop integrating their cards on every machine ... though I could understand it with a laptop (Graphics Accelerator X3100 with up to 384 MB of DV memory.) Anyway, the main reason I truly wanted to switch back to XP is that I'm hoping it will help free up memory to enhance my graphics for Counter-Strike: Source. crassic!^[talk] 01:41, 14 March 2008 (UTC)

I was still playing CS:S when vista came out; be aware that I actually had an increase of 2-3fps when I installed vista. Yah- my fps increased. I do have 2GB of memory though and I can take a bit of Vista overhead. But the XP video and audio interfaces/stacks are ancient; I guess Vista's are more efficient, even with all the DRM :[ :D\=< (talk) 03:11, 14 March 2008 (UTC)

Wow, it increased with Vista? A bit shocking to me, but meh. I actually only get about 9fps due to both of my computers having integrated video cards. So honestly, going back to XP wouldn't help much - or at all? crassic!^[talk] 03:40, 14 March 2008 (UTC)

NINE fps? How can you play?! :D\=< (talk) 03:58, 14 March 2008 (UTC)

Haha. I generally get good fps on fight yard (fy) maps, somewhere in the range of 40 (though I could be mistaken. It's been a while.) But 80% of the time I'm on, I stick to playing 1.6 or CZ. crassic!^[talk] 04:50, 14 March 2008 (UTC)

I get better fps on the Source engine (lowest settings except 1400x1050 resolution) than on the GoldSrc engine (any settings, doesn't matter). I guess my card doesn't do opengl well or something, but CS and CZ are really choppy :D\=< (talk) 07:58, 14 March 2008 (UTC)

Didn't Microsoft severely crippled OpenGL in Vista by removing it and leaving it up to the manufacturers to implement it or something like that? --antilived^{T | C | G} 05:27, 15 March 2008 (UTC)

Not according to the people that maintain OpenGL. It's the same as in XP (though slower, as with DirectX, because the driver architecture is different and the gpu companies are still adjusting.) -- Consumed Crustacean (talk) 06:28, 15 March 2008 (UTC)

Converting Outlook mail to Mbox

Hi. I am trying to import my mail from Outlook to Mozilla Thunderbird. If I use Thunderbird's import feature, any international character in the bodies of some messages becomes corrupted (and no character encoding tweaking on Thunderbird's end will help). If I import to Outlook Express and then to Thunderbird, the subject lines become corrupted on the Outlook -> Express step.

So, does anyone know a solution to this problem? Perhaps some script I can run that will hybridate the correct subject lines from one version of the mail with the correct bodies of the other? Or a different program to do the conversion? I have encountered an Outlook plug-in called MessageSave that can do the trick, but its trial version is too limiting and its full version is too pricey. Does anyone know of a free alternative, or at least one with a better cost / value?

Thanks. 79.178.115.92 (talk) 11:19, 13 March 2008 (UTC)

I've used Aid4Mail (which is commercial, if not terribly expensive) to interchange mail from a variety of formats, and in particular moving Outlook PST archives (which are its equivalent of MBOX files) to EML files that Thunderbird will read (so I'd have Outlook export a folder or account to PST, then have Aid4Mail turn them into EML files). While there are some open source libraries that claim to read Outlook's proprietary formats (and the different, incompatable, and proprietary Outlook Express formats) they don't appear to be heavily maintained and the tools that use them don't seem terribly effective. Update: Ah, I checked MessageSave's price, which is the same as Aid4Mail, so maybe this isn't what you're looking for. -- Finlay McWalter | Talk 11:30, 13 March 2008 (UTC)

Well, on one hand, Aid4Mail can do a lot more than MessageSave. On the other hand, it seems to still have problems with some of the messages. Since all I want is to convert my mail to mbox and forget any other format ever existed, I've decided to purchase MessageSave. Thanks for the help. 79.178.115.92 (talk) 14:31, 13 March 2008 (UTC)

Aid4Mail is great if you, like me, were going to be exchanging mails in various formats on a regular basis; it's a sorry state of affairs when someone who, like yourself, has to buy software just to get control of their own data for a one-time migration. If you're up for a bit of labour, you could try the following: get yourself an IMAP email account and configure both Outlook and Thunderbird to access it (Outlook, as usual, will try to do vexing things like download all the mail unless you make sure it knows not to). Then, in Outlook, drag your emails (ideally en-masse) from your existing account to the IMAP account (it should copy them up). Then, when they're all copied, use Thunderbird to drag them back down from the IMAP server to a local thunderbird folder (or you could choose to keep them in IMAP land permanently). -- Finlay McWalter | Talk 18:10, 13 March 2008 (UTC)

Removal of icon from Sys Tray?

Hey there,

I'm running Google Web Accelerator, but I don't want it to show on the sys tray. Can I get rid of the icon on Windows XP, while still using it?

Perfect Proposal ^{Speak Out!} 14:22, 13 March 2008 (UTC)

If you just want to hide it so that it doesn't show on the first sight (i.e. you'll have to click on the arrow at the left end of the sys tray to show the hidden icons), then you can right-click on the taskbar, go to properties, click customize, find the web accelerator and select the option "always hide" from the drop-down menu. I'm not sure if you can totally remove it, there might be an option for it in the program's options menu though, why don't you look thru it?  ARTYOM  16:43, 13 March 2008 (UTC)

Thanks! Perfect Proposal ^{Speak Out!} 00:18, 14 March 2008 (UTC)

Google Maps

Hello. When I open a Google Maps info window on the toolbar, I can only locate my destinations. When I ask for directions, a new Internet Explorer 7 window appears instead of a new tab. My tab settings are set such that programs open links in a new tab in the current window. How can I fix this? Thanks in advance. --Mayfare (talk) 15:15, 13 March 2008 (UTC)

Maybe try holding down ctrl as you click, or right click and "Open in new tab." Or just try Firefox. --Ephilei (talk) 04:24, 14 March 2008 (UTC)

Wait. That does not work. --Mayfare (talk) 20:31, 19 March 2008 (UTC)

Ultimate Bluetooth Mobile Phone Spy Software New Edition 2008?

How does this work exactly? What do I need to do in order for this work? Has anyone used this before? --Jonasmanohar (talk) 16:36, 13 March 2008 (UTC) www.bluetooth-spy-software.com --Jonasmanohar (talk) 16:44, 13 March 2008 (UTC)

It seems to be a program to grab data (SMS, phonebooks) from other cellphones via Bluetooth. Let's see...

• Title: 0/5
• Website design: 0/5
• Price: -1/5
• Features: 2/5
• Overall rating: 0/5

Other things to notice:

• Settings screenshot is from Blooover
• The four "Actions" shots are from BT Info
• One screenshot is from EasyJack

Overall rating: SCAM!

I suggest you to try BT Info instead of wasting money. --grawity ^{talk / PGP} 17:29, 13 March 2008 (UTC)

I'm sorry, Grawity, do you mind this in layman's terms? Also, how do I use the link you just provided? --Jonasmanohar (talk) 18:11, 13 March 2008 (UTC)

Bluetooth is a short-range (10 or 100 m) wireless connection, usually between two mobile phones.

There are programs that let you control other phones via Bluetooth - steal phonebooks and SMS, play sounds, call someone, usually without phone owner's knowledge.

The program you linked to claims to do exactly that, but:

• The screenshots (pictures) are actually from other programs. I've recognized BloooverII, BT Info and EasyJack. So in fact they're selling programs which are created by others and available for free.
• The website's design is AWFUL. I don't trust any website which has such design.

In short, it is a scam.

If you have a phone with Bluetooth (and know how to use it), download BT Info (click "ftp_bt 1.08") and copy it to your phone. --grawity ^{talk / PGP} 08:46, 14 March 2008 (UTC)

Isn't Bluetooth communications encrypted precisely to prevent this sort of thing? Why would anyone use it if this is possible? -- Meni Rosenfeld (talk) 10:48, 14 March 2008 (UTC)

Yes, Bluetooth is encrypted, but the idea is that if you connect ("pair") two devices, for example, your and my phones, they both trust each other - I can connect to any paired device and most of them either do not ask owner for permission or are set to "always allow". Also, you can set your device name to "Enter 1234", go into a mall, and try to pair with everyone (using PIN 1234).

So now our devices are paired, and your phone allows mine to connect - and I do. You probably click "Allow" before even reading that darn popup which just appeared, and then I have absolute control over your phone. (That is, while your phone is in the range - 10 meters, or in some phones 100 m.) I can make your phone call me (and listen to whatever you're doing), I can change language (to Chinese for example), start a MP3, edit phonebook.

The problem is that you're not supposed to add a device if you don't trust its owner. --grawity ^{talk / PGP} 14:50, 14 March 2008 (UTC)

That website almost certainly breaks laws eg passing off I'm not even going to try clicking on it as it sounds like an virus nest. Perhaps someone who knows what to do would care to report this to a regulatory body.87.102.83.204 (talk) 11:21, 14 March 2008 (UTC)

As far as I'm concerned LARGE RED LETTERS mean only one thing - virus or spyware or spam or trojan. Give it a miss.87.102.83.204 (talk) 11:23, 14 March 2008 (UTC)

Simulating PowerPoint's increase/decrease font size features in OpenOffice.org Impress

In PowerPoint, you can select a block of text and adjust the font size (upward or downward) by clicking the "increase font size" or "decrease font size" buttons. These buttons increases/decreases the font size of the selected text to the next predefined font size in the "font size" dropdown list. If original font size is between two predefined font sizes, the adjusted font size will be between two (new) predefined font sizes, too. In other words, relative font size is preserved in the adjustments.

These functions are not available natively in OpenOffice.org Impress. Is there simple way to add these functions to Impress, perhaps by means of an extension or via OpenOffice.org Basic macros? --71.162.242.230 (talk) 16:21, 13 March 2008 (UTC)

Linux System Calls

What methods there are to do system calls on Linux, from x86 assembly viewpoint? It was easy enough to find int 80h, but what about mysterious glibc & others? I'm such of a hobbyist in all this (weird that way, should I say) that I don't have any clue on how they work. I'd just like to see a somewhat complete list here of elsewhere. --212.149.217.84 (talk) 18:14, 13 March 2008 (UTC)

I only know a little assembly but it seems like since the kernel is written in C and has a C interface, you'd need to use C :D\=< (talk) 18:38, 13 March 2008 (UTC)

This site will get you started. The basic idea is that you stick a syscall number from /usr/include/asm-i386/unistd.h into %eax, then put argument 1 in %ebx, argument 2 in %ecx, and so on. Do the int $0x80 to trap into the kernel, and get the return value out of %eax. E.g., to call time(), which is syscall #13, we do:

       movl    $13, %eax
       movl    $0, %ebx
       int     $0x80

Now %eax will contain the current unix time. As for glibc, that's just a normal user space library (albeit one that makes heavy use of system calls), and has nothing to do with them per se. --Sean 19:39, 13 March 2008 (UTC)

Very cool.. but seeing as how there's no way within C to actually get those values out of EAX and EBX I assume that that part of the kernel is written in Assembly.. but then how does that do the actual syscall? Most of the kernel functions are written in C; how do you call a C function from assembly? And doesn't that sap portability teh ridiculous? How does the ultimate of portables NetBSD handle syscalls from within asm? :D\=< (talk) 18:11, 19 March 2008 (UTC)

Simulating PowerPoint's increase/decrease font size features in OpenOffice.org Impress

In PowerPoint, you can select a block of text and adjust the font size (upward or downward) by clicking the "increase font size" or "decrease font size" buttons. These buttons increases/decreases the font size of the selected text to the next predefined font size in the "font size" dropdown list. If original font size is between two predefined font sizes, the adjusted font size will be between two (new) predefined font sizes, too. In other words, relative font size is preserved in the adjustments.

These functions are not available natively in OpenOffice.org Impress. Is there simple way to add these functions to Impress, perhaps by means of an extension or via OpenOffice.org Basic macros? --71.162.242.230 (talk) 16:21, 13 March 2008 (UTC)

Explorer.exe large Virtual Memory usage

Hello to all. All my problems started when I was writing a program in Python (PythonWim IDE), requesting it to store quite large bitmap in memory, and then write it to a file. In calculating what to put in its header as width and height, I divided wrongly by 16 instead of 256, and ended up with astronomically large width and height values (57000x12000). Upon attempting to view the file (from my desktop) in Paint, everything locked up, needing to be resolved by closing a few processes (including explorer.exe).

Upon restarting the explorer.exe process, it began with quite a small amount of virtual memory usage (5000 kB), then suddenly jumping to 600 000 kB and locking up. Of course, I tried a reboot, but it didn't work. The problem does not seem to occur on other accounts apart from mine (the only administrator account).

To try to solve it, I fired up WinDbg and chose Step over many times until finally reaching the point where memory usage darted up. It did so in two stages: first to 250 000 kB, then to 600 000 kB. The error seems to occur in the BrowseUI.dll module of the explorer.exe process. This is the output of !analyze -v:

==================
Exception Analysis
==================

FAULTING_IP: 
GDI32!StretchDIBits+1bd
77f2c6ec f3a5            rep movs dword ptr es:[edi],dword ptr [esi] 
Attempt to read from address 

FAULTING_THREAD:  000009b0
DEFAULT_BUCKET_ID:  APPLICATION_FAULT
PROCESS_NAME:  explorer.exe
ERROR_CODE: (NTSTATUS) 0xc - The instruction at "0x%08lx" referenced memory at "0x%08lx". The memory could not be "%s".
READ_ADDRESS:   
BUGCHECK_STR:  ACCESS_VIOLATION
LAST_CONTROL_TRANSFER:  from 7e to 77f2c6ec
STACK_TEXT:  
00ece84c 7e  GDI32!StretchDIBits+0x1bd
00ece898 7e  USER32!SmartStretchDIBits+0x16e
00ece8ec 7e  USER32!BitmapFromDIB+0x1cf
00ece934 7e4284aa 2021000e  USER32!ConvertDIBBitmap+0x10a
00ecedec 7e 00ecf  USER32!RtlLoadObjectFromDIBFile+0x2e4
00ecee10 7e4254de 7e 00ecf USER32!ObjectFromDIBResource+0x25
00ecee60 7e422d2a   USER32!LoadBmp+0x4b5
00ecee84 7e 00ecf USER32!LoadImageW+0x7c
00eceed4 7e444d0a 00ecf  USER32!ExtractIconFromBMP+0x35
00ecf340 7ca2239b 00ecf  USER32!PrivateExtractIconsW+0x202
00ecf384 7ca232be 00ecf 0000000a SHELL32!SHDefExtractIconW+0xe7
00ecf3b0 7ca232e7 00ecf 00ecf420 SHELL32!CExtractIcon::_ExtractW+0x82
00ecf3cc 7ca22a09 001521ec 00ecf554 0968ebb5 SHELL32!CExtractIconBase::Extract+0x1f
00ecf3f4 7ca228d2 001521ec 00ecf554 0968ebb5 SHELL32!IExtractIcon_Extract+0x35
00ecf760 7c9f6015 001521ec  01d0d2f0 SHELL32!_GetILIndexGivenPXIcon+0x29e
00ecf788 7c9fd9ce 000f0f18 001521ec 01d0d2f0 SHELL32!SHGetIconFromPIDL+0x90
00ecfe04 7ca04859 000f0f1c 01d0d2f SHELL32!CFSFolder::GetIconOf+0x24e
00ecfe20 7c9fb22e 000f0f1c 01d0d2f SHELL32!CDesktopFolder::GetIconOf+0x35
00ecfe40 7ca22a64 000f0d20 000f0cbc 01d0d2f0 SHELL32!SHGetIconFromPIDL+0x20
00ecfe68 7c9f209d 01d0d2a0 01e0c608 01eef838 SHELL32!CGetIconTask::RunInitRT+0x47
00ecfe84 75f81b9a 01d0d2a0 75f81b18 75f80000 SHELL32!CRunnableTask::Run+0x54
00ecfee0 77f69498 01de57f8 01d8c748 77f6947b BROWSEUI!CShellTaskScheduler_ThreadProc+0x111
00ecfef8 7c 01d8c748 7c97c3a0 000febe0 SHLWAPI!ExecuteWorkItem+0x1d
00ecff40 7c 77f6947b 01d8c ntdll!RtlpWorkerCallout+0x70
00ecff60 7c 01d8c748 000febe0 ntdll!RtlpExecuteWorkerRequest+0x1a
00ecff74 7c92761c 7c 01d8c748 ntdll!RtlpApcCallout+0x11
00ecffb4 7c80b 7ffd0000 7c ntdll!RtlpWorkerThread+0x87
00ecffec  7c  kernel32!BaseThreadStart+0x37

FOLLOWUP_IP: 
BROWSEUI!CShellTaskScheduler_ThreadProc+111
75f81b9a 8945fc          mov     dword ptr [ebp-4],eax 

SYMBOL_STACK_INDEX:  15
FOLLOWUP_NAME:  MachineOwner
MODULE_NAME: BROWSEUI
IMAGE_NAME:  BROWSEUI.dll
DEBUG_FLR_IMAGE_TIMESTAMP:  47589cbf
SYMBOL_NAME:  BROWSEUI!CShellTaskScheduler_ThreadProc+111
STACK_COMMAND:  ~8s ; kb
FAILURE_BUCKET_ID:  ACCESS_VIOLATION_BROWSEUI!CShellTaskScheduler_ThreadProc+111
BUCKET_ID:  ACCESS_VIOLATION_BROWSEUI!CShellTaskScheduler_ThreadProc+111

As convenient as it would seem to an assembly-language programmer, it is still giberish to me. Please help me regain control of explorer.exe, as it is extremely inconvenient to work without making use of the desktop or of the file manager.

--Danielsavoiu (talk) 18:22, 13 March 2008 (UTC)

It looks like what's happening is Windows is trying to process the file to give you a nice icon for it, but choking on the large file. I would try to get access to the disk somehow (boot into DOS or whatever kind of single-user mode equivalent Windows has, or do it from another account if possible), and go and delete the bad file. I'm always amazed at how hard and noisily Windows sucks! :) --Sean 19:47, 13 March 2008 (UTC)

Thank you, Sean. It is also amazing how the human mind seeks to solve problems in a much more complicated way then necessary. To think that I tried debugging the whole process before trying to delete the file. Indeed, your advice worked perfectly. Thank you once more. --Danielsavoiu (talk) 19:59, 13 March 2008 (UTC)

NFS Permission Problem

I have a fileserver. /home is owned by root:users and 777. Inside that is library owned by root:users and 777. Inside that is text files owned by root:users and 666. All users are in group users. I NFS mount /home/library. On the fileserver, exports is using rw,no_root_squash,async. On the local computer, it mounts as nfs rw. I ensured all user and group IDs are the same between both machines. I can read files fine. When I try to save a file, it deletes the contents of the file and then complains that the local user doesn't have rights to save the file. If I change the owner of the file to the local user, I can open and save without problems. I need for all members of group users to be able to read/write the files. I really need to stop the current experience of clicking "save" and having it delete the contents of the file and then throw a permission error. Is there something obvious that I am missing? -- kainaw™ 18:41, 13 March 2008 (UTC)