Wikipedia:Reference desk/Archives/Computing/2010 July 25

= July 25 =

Laptop not booting every time
I have a HP dv5 laptop that's seen about one year of use now and for quite a while I have been having a problem booting up. It will usually take a couple of tries, when turned on, the splash screen appears, after this, sometimes the grub menu will load if is booting correctly, otherwise the screen just stays blank and it hangs there (no beep sequence). I don't know if it's just wishfull thinking but it does seem to boot more easily when it has only been hibernated as opposed to turning it off completely, and loading the BIOS and simply going to Exit>Saving changes seems to yield better results. As I said, thats probably just wishfull thinking. Especially since some googling suggested that it's probably a hardware related problem.. Any ideas? Benjamint 01:19, 25 July 2010 (UTC)
 * You didn't mention what OS(s) you're running.--mboverload @ 01:32, 25 July 2010 (UTC)
 * Vista Benjamint 06:24, 25 July 2010 (UTC)
 * Use the Vista CD to repair the startup procedure. Any particular reason you're using Grub? --mboverload @ 05:47, 26 July 2010 (UTC)

My first ever computer was a Windows 3.1 portable "lunchbox" computer (similar to the one in this pic but bigger, less advanced and with a garish orange monochrome screen) which I bough for £1 at a jumble sale. At first I thought it didn't work because when I turned it on always froze at the start of the boot sequence, exactly like the problem you're having. Presumably the sellers thought this too which is why they sold it so cheep (although it was way outdated even then and wasn't worth more then £1 anyway). Long story short, I discovered that quickly turning it on then off before turning it on for a second time made it boot normally. I have no idea why it did this, I only know that unless you did the special on then off then on again trick, the thing simply would not boot. 82.43.90.93 (talk) 10:41, 25 July 2010 (UTC)

Free spreadsheet with nameable cells
I'm looking for a spreadsheet where the columns are easily sortable. This means that the normal convention of refering to cells by their row and column position will not work. Therefore, are there any free spreadsheets where the cells are named instead? Thanks 92.29.122.159 (talk) 12:35, 25 July 2010 (UTC)


 * The usual way of creating a spreadsheet where the columns are easily sortable is to give each column the name you want in its first row; so A1 contains the word "First Name", B1 contains "Middle Name", C1 contains "Last Name", etc.. When you sort the columns, you do so by row 1; and you make sure not to include row 1 in any other sorting or manipulation you perform.  A spreadsheet without row and column position notation sounds like an awful idea, to be honest.  If you could describe what exactly it is you are looking to do, we might be able to help further within the constraints of Excel and OpenOffice Calc.   Comet Tuttle (talk) 21:16, 25 July 2010 (UTC)


 * A spreadsheet without numbers sounds a lot like a functional programming language to me. From what I understand, finance institutions are known for growing huge, unwieldy spreadsheets, and then (sometimes) switching to doing everything in a language like ML instead, so it's not an unknown connection.  Paul (Stansifer) 04:49, 26 July 2010 (UTC)
 * "A spreadsheet without numbers sounds a lot like a functional programming language to me" More simply, I would think of it as a hashtable or a relational database (but by "spreadsheet", people generally mean a certain type of MS Excel-like interface, rather than the underlying data structure). Apokrif (talk) 11:05, 28 July 2010 (UTC)

I think Quantrix and the other spreadsheets linked from that article do not use the row/column naming convention. I would like to be able to sort any column, not just the first one. 92.15.0.178 (talk) 20:23, 26 July 2010 (UTC)

Reducing file size of PDFs
Can anyone recommend some free software to reduce the file size of PDFs please? Including changing from colour to monochrome. Thanks 92.29.122.159 (talk) 12:40, 25 July 2010 (UTC)
 * Have you tried just compressing them? WinRAR, 7zip can do this 82.43.90.93 (talk) 13:26, 25 July 2010 (UTC)
 * If you don't want to compress them, you could just recreate them by printing the page to something like Cute PDF Writer (free), but this isn't an elegant solution, especially if there are many pages. (ADOBE have editing software but you probably have to pay for it.)    D b f i r s   16:22, 25 July 2010 (UTC)

Question (Quick Response Code)
What is this and what is one meant to do with it? 82.43.90.93 (talk) 13:30, 25 July 2010 (UTC)


 * It's a QR Code. It encodes some information, and what you'd use it for depends on the information. I don't know the Google chart API very well, but in this case it looks like its encoding a URL (in this specific case, the URL of an executable file) as a QR Code. -- Finlay McWalter • Talk 13:37, 25 July 2010 (UTC)


 * And indeed you can paste the URL of a QR Code (or upload the image of one) into this online app and it decodes it for you. -- Finlay McWalter • Talk 13:39, 25 July 2010 (UTC)

Thanks 82.43.90.93 (talk) 13:41, 25 July 2010 (UTC)


 * Here's the QR code on the Google Code download page it came from. If you hover over the image it explains it's a "File download URL". Presumably, the QR codes seen on Google Code download pages are meant to be photographed and decoded by mobile phones to download files. --Bavi H (talk) 00:46, 26 July 2010 (UTC)

Hi, I've changed the title of your post from "Question" to "Question (Quick Response Code)", so that it is more meaningful.

wget
Is there a way to make wget download all the html files first when mirroring a site, before downloading the images? 82.43.90.93 (talk) 17:04, 25 July 2010 (UTC)


 * I'd run it twice: the first time using  so that it doesn't download files with these extensions, and the second time using   so it doesn't redownload files it got the first time. &mdash;Korath (Talk) 17:31, 25 July 2010 (UTC)

"Joining" graphic files
Seems simple in concept: say I have 8 JPEGs and want to join 1.jpg through 4.jpg horizontally, then "add a new row" by joining 5-8 below them. I have searched for software (preferably command-line) that will perform this, without luck so far. I'm not looking for fancy algorithms involving stitching, but simply want to produce one large graphic canvas by joining a variety of smaller files horizontally. Any recommendations? I prefer command-line because ideally I'll be automating this as much as possible. Thanks, Riggr Mortis (talk) 21:44, 25 July 2010 (UTC)


 * I'm almost certain that ImageMagick's "montage" feature will do this (although it might need three calls) from the command line. I'll check the exact syntax momentarily. -- Finlay McWalter • Talk 21:46, 25 July 2010 (UTC)


 * Ha, I just landed on ImageMagick as well. Seems my Google-Fu was not up to snuff last time around. There's a bit of a learning curve there so if there are any other (single-purpose) options around I'm still ears. Riggr Mortis (talk) 21:55, 25 July 2010 (UTC)


 * ImageMagick is very powerful, but the documentation for it can be a bit daunting.  I didn't find the main doc very useful, but that pointed me at this which is just the ticket. Accordingly I think you need to say:

montage -tile 4x -geometry +1+1 *.jpg OUTPUT.jpg
 * or

montage -tile 4x -geometry +1+1 1.jpg 2.jpg 3.jpg 4.jpg 5.jpg 6.jpg 7.jpg 8.jpg OUTPUT.jpg
 * The tile option puts them into rows of 4, the geometry option puts a single pixel between them horizontally and vertically (I think if they're all the same size, and you give +0+0 as the geometry, then you'll get a perfect tile). -- Finlay McWalter • Talk 22:01, 25 July 2010 (UTC)


 * Works perfectly. I was wondering about the simplest way to avoid specifying every file name. Wildcards work; "tile*.jpg", but I'm not clear yet if that will "sort" them in the proper numerical sequence (likely not; perhaps if the filename numbers are zero-padded it might). I don't see anything yet in the page you linked that provides for this sort of logic. With potentially a few hundred small files, I wonder if I would have to create the command line in Excel... :-) Hopefully not. Thanks, Riggr Mortis (talk) 22:13, 25 July 2010 (UTC)


 * If you were using Linux (etc.) you'd just say montage -tile 4x -geometry +1+1 `ls *.jpg | sort` OUTPUT.jpg (and specify whatever arguments you needed to to sort to get the ordering you wanted). I don't know what you'd do on the CMD.EXE command line to get the same (and last time I did serious scripting on Windows, which was a long time ago, there were horrible limitations as to the maximum length of command line arguments, even if you built them with a script). -- Finlay McWalter • Talk 22:30, 25 July 2010 (UTC)


 * Actually ls has its own sort options, which are probably better than using an external sort, but as it seems you're using Windows, that's probably cold comfort, so I'll not rub in any further salt. -- Finlay McWalter • Talk 22:34, 25 July 2010 (UTC)


 * Made it this far, but stumped by the file input order. I have 180 images named sequentially, "000.jpg". It processed the first half of them in order, apparently by coincidence, because the bottom half runs into trouble. There's got to be a way... yes, in "DOS", or in the program itself. You can pipe input on the command line I believe, but I'm not sure if it would work in this context. Riggr Mortis (talk) 23:47, 25 July 2010 (UTC)
 * Never mind, it may just work. My file numbering (dealing with a jig-saw puzzle) appears to be the problem. Riggr Mortis (talk) 00:06, 26 July 2010 (UTC)
 * For the record, the wildcard "*.jpg" works fine regarding sort order. My preferred naming convention was "00-00.jpg" (row, column), and that worked. Either Windows provides the filenames to the program in standard sort order, or the program sorts them. Thanks for your help. Riggr Mortis (talk) 00:28, 26 July 2010 (UTC)


 * For the (same?) record, Windows does have rudimentary shell scripting these days; the for command should be able to help you with sorting if the default doesn't work. Type "help for" at the command line to see the options. (Writing this on Vista but it should be in WinXP as well. Probably not in pre-NT, though.) Jørgen (talk) 15:30, 26 July 2010 (UTC)