Wikipedia:Reference desk/Archives/Computing/2011 February 13

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February 13

QVOD player

My mother is using the QVod player to watch videos and after downloading videos, she is unable to watch any of the videos downloaded. It displays a black screen with the file name on it. It worked earlier yesterday but no longer works. The only change to my computer was the installation of Real Player. My cursory search on Google shows nothing. Could this be a video car problem? Could this be a software problem? What should I do? --Blue387 (talk) 04:15, 13 February 2011 (UTC)

This might be a video codec problem, but I'm not sure. --Blue387 (talk) 04:31, 13 February 2011 (UTC)

I have installed the latest version, fixing my problem. Never mind. --Blue387 (talk) 04:46, 13 February 2011 (UTC)

Have you tried another player? General Rommel (talk) 10:37, 13 February 2011 (UTC)

Avoiding the double-plug cables with USB bus powered devices.

I have seen portable hard drives, optical drives, and even scanners that get both power and data from a single USB connection. However, most include a Y-shaped cable with two USB type A plugs on one end. The manuals state this is for USB ports that don't provide "full USB power". A user plugs both of them in to get enough power for the device on the other end of the cable. So what is full USB power? And why is 2X low power always enough power? I hate having to deal with special cables. What should I look for when buying a USB hub to make sure each port provides full USB power for each of my devices? --68.102.163.104 (talk) 04:30, 13 February 2011 (UTC)

If you want to be sure each port of a hub provides enough powr, get a self powered hub (i.e. one that comes with a seperate power adapter that you plug in to the wall) Nil Einne (talk) 05:13, 13 February 2011 (UTC)

Right. I have one, but apparently it isn't giving bus-powered devices enough power. Which is why I'm asking my original question. --68.102.163.104 (talk) 16:15, 13 February 2011 (UTC)

You have a self powered hub, ones that includes a power adapter to attach to the wall but it still doesn't provide enough power? This is rather odd, I would suggest the hub is potentially defective. Nil Einne (talk) 15:03, 17 February 2011 (UTC)

I agree. I would remove all the USB cables and check one of the USB outputs for 5v. I have a USB breakout box I use for this purpose. As to "full USB power", it depends on the device. Universal Serial Bus#Power states "Some devices like high-speed external disk drives may require more than 500 mA of current and therefore cannot be powered from one USB 2.0 port. Such devices usually come with Y-shaped cable that has two USB connectors to be inserted into a computer." I have an older USB 2.5" hard drive that includes a power cable that connects to a PS/2 port— I had to use it on older laptops, but not my current laptop. ---— Gadget850 (Ed) ^talk 15:24, 17 February 2011 (UTC)

rsync question

Is there an option in rsync to delete all files on the receiver that are not found on the sender? The man page mentioned "--del", is this what I want? JIP | Talk 09:33, 13 February 2011 (UTC)

It might, as it depends on how you call rsync.

ls /source
foo
bar
ls /destination
foo
ney
rsync -aPv --delete source/ destination/
ls /destination
foo
bar

but:

ls /source
foo
bar
ls /destination
foo
ney
rsync -aPv --delete source/* destination/
ls /destination
foo
bar
ney

-- 78.43.71.225 (talk) 20:07, 14 February 2011 (UTC)

I assume this is because rsync -aPv --delete source/* destination/ is equivalent to rsync -aPv --delete source/foo source/bar destination/ (in this case), so rsync does not even consider the file ney as part of the backup process? JIP | Talk 07:26, 15 February 2011 (UTC)

Apple Mac

How do I move a downloaded program from downloads to memory stick please? Kittybrewster ☎ 11:09, 13 February 2011 (UTC)

There are many different ways, but the simples one is probably to insert the USB stick, open two finder windows (using Cmd-N or "New Finder Window" from the File menu), navigate to the Download folder in one window, to the USB stick in the other (it should be in the sidebar of the Finder window - if not click on the small grey oval in the upper right corner to expand the window), and simply drag the file over from one to the other. --Stephan Schulz (talk) 11:18, 13 February 2011 (UTC)

[JavaScript] Not a number

In Firebug:

>>> parseFloat('HELLO!');
NaN
>>> typeof(parseFloat('HELLO!'));
"number"
>>> if (parseFloat('HELLO!')==NaN) { alert('NOT A NUMBER!!!') };
undefined

Isn't it kind of stupid that the type of NaN is "number"? How do I check NaN? -- Toytoy (talk) 12:34, 13 February 2011 (UTC)

You're looking for isNaN(number). --dapete 13:02, 13 February 2011 (UTC)

It is sort of wacky, but the IEEE standard for floating-point defines 'NaN' as a special floating-point value to be used when the result of an operation is not a defined number (5 divided by 0 results in NaN, for example). When types are used for performance reasons, it's really useful to know the type of the result an operation in advance (without knowing what the arguments are), so in that way, it's a useful convention that NaN is a floating-point value. Paul (Stansifer) 13:57, 13 February 2011 (UTC)

Special bonus trivia: You can generally test for x being NaN with x != x; the standard also defines that NaN is not equal to anything, including itself. This is, of course, kind of horrifying, if you expect equality to be an equivalence relation. Paul (Stansifer) 18:54, 13 February 2011 (UTC)

5/0=inf, not nan. 0/0=nan (but not ==, of course, as Stansifer said). --Tardis (talk) 15:00, 14 February 2011 (UTC)

Thank God I learned to do math before I am polluted by computer science conventions! Ha! -- Toytoy (talk) 11:54, 14 February 2011 (UTC)

Now I'm curious. What should typeof(parseFloat("!")) return, in your un-sullied opinion? --Tardis (talk) 16:02, 14 February 2011 (UTC)

Harumph! Computer scientists are perfectly happy to specify a solution that takes thirty times as long to do arithmetic, but does the right thing. The mathematical weirdness here is all caused by compromises made with software engineering constraints. You can blame all those annoying consumers who wanted to play Doom at more than 3 frames per second. Paul (Stansifer) 17:16, 15 February 2011 (UTC)

Vista - 'Read Only'

Hi everyone - I am trying to remove the 'Read Only' thingy from a folder (and subfolders there-in) which I have here on my computer. Right clicking 'Properties' and un-checking 'Read Only' seems to do the job well enough, until I right-click 'Properties' again straight afterwards only to find it is 'Read Only' again. No matter what I do, this 'Read Only' still persists. I have used Start Menu>Explorer.exe (Run as Admin) to no avail. I have tried with the folder in Program Files (where it was to start off with), in Documents, and on Desktop, all to no avail. Is there anything I can do to accomplish this? --KägeTorä - (影虎) (TALK) 12:58, 13 February 2011 (UTC)

I had this same problem under Windows 7 -- when trying to remove the read-only attribute from a folder in Program Files, Windows would tell me that something had happened, but the folder was still read-only. I believe you have to right-click on the folder, click Properties, then Security and give yourself "Full Control". I found this guide that outlines that process, but it seems to go more in-depth that is needed (actually giving you ownership of the folder, rather than just permission to modify the files). Xenon54 (talk) 17:02, 13 February 2011 (UTC)

Excellent! --KägeTorä - (影虎) (TALK) 00:17, 15 February 2011 (UTC)

In the the Properties of a folder, the Read-only checkbox is used to change the status of all the files in the folder, but doesn't show or change the read-only status of the folder itself. When you open the Properties of a folder, the Read-only checkbox always shows a half-way gray state contains a square (or a light gray checkmark). This means "don't make any changes to the read-only status of the files in this folder." You can then check or clear the box and click OK to change all the files in the folder to read-only or read-write.

The actual read-only bit of a folder is used by Windows for purposes other than restricting write access. If you really need to see or change it, you can use the attrib command, as described in the Microsoft support doucment below.

• You cannot view or change the Read-only or the System attributes of folders in Windows Server 2003, in Windows XP, in Windows Vista or in Windows 7
• Folder keeps changing back to read-only. What permissions setup causes this in Windows?

--Bavi H (talk) 19:43, 13 February 2011 (UTC)

'Half way gray state'? No idea what that means - full blue box on my machine. Anyway, cheers. --KägeTorä - (影虎) (TALK) 00:15, 15 February 2011 (UTC)

You're right. It's called a tri-state checkbox. In the default display style in modern Windows versions, the third state has a square in the box. When Windows XP is set to Windows Classic display style, the third state is a light gray checkmark, like this: tristate.gif. "Half way gray" was unclear so I revised it above. --Bavi H (talk) 02:32, 15 February 2011 (UTC)

Severe Bluescreen problem - I may have to format and reload Windows 7

I think I have got some viscious malware as I haven't installed any new software and I haven't attached any new hardware - but suddenly I am getting the bluescreen seconds after windows7 finishes loading. The bluescreen gives a variety of 'reasons'. Once it told me it had a problem with CDROM.SYS and once that I had a "system service" problem - that one also gave me an error code (0x80070002). Mostly it just tells me "IRQL not less or equal" then shuts down.

I have booted in safe mode and gone back to a known safe restore point but it still happens - weird!

I suspect that I may have to reinstall Windows (Yeuk!) but if I do I want to do the job REALLY thoroughly and run a low level format of my C drive first.

QUESTIONS: 1. How do I do a low level format prior to reinstalling? 2. Has anyone any bright ideas that may save me from the dreaded reinstall?

I am currently running on an old PC running Windows XP - I just LOVED XP.

Hoping you can help. Gurumaister (talk) 14:04, 13 February 2011 (UTC)

Before you do this, try the following.

1. Boot up in "Safe mode with Networking"
2. Go to http://www.malwarebytes.org/ and download the free version
3. Update it
4. Run it

This utility can clean up a lot of malware w/o having to redo your installation from scratch. Exxolon (talk) 16:25, 13 February 2011 (UTC)

Exxolon - that was excellent advice. thank you. I have loaded and run Malwarebytes and I seem to have a stable (so far) system. I am very grateful! Gurumaister (talk) 17:13, 13 February 2011 (UTC)

Svg vs GIF

Svg vs Gif which is better and why Rahul^{Text me} 17:28, 13 February 2011 (UTC)

SVG is good for drawings, cartoons, diagrams, etc, but not for photographic images. GIF is really an obsolete format for any purpose except animation. For photos, Jpeg is usually the best choice unless you need perfect precision, in which case PNG is usually the best choice. Looie496 (talk) 17:49, 13 February 2011 (UTC)

They fit different purposes. GIF is a relatively old format for raster graphics, whereas SVG is a format for vector graphics. In other words, an SVG file is a set of instructions on how to draw a picture at any size, whereas a GIF file is a picture of fixed size (in pixels).

For most purposes, GIF has been obsoleted by PNG and JPEG. GIF only supports 256 colors in one picture and single-bit transparency, whereas PNG and JPEG support millions of colors. But there's one thing GIF can do that PNG and JPEG can't: animation. GIF is widely used on the Web for small, compact animated images.

Wikipedia uses SVG extensively for things like logos, maps, and other drawn graphics which may need to be resized, or printed at different resolutions. This is because you can resize a vector image without losing image quality, whereas a raster image (like a GIF or PNG) loses information when shrunk and becomes "pixelated" when scaled-up. But SVG isn't useful for photos, since digital photos are raster data. --FOo (talk) 17:52, 13 February 2011 (UTC)

Actually PNG can do animation, see APNG 82.43.92.41 (talk) 18:06, 13 February 2011 (UTC)

APNG is an unofficial extension to PNG that was rejected by the PNG group. Using it on Web sites would be a bad idea since less than 50% of all Web users can view it: it's not supported by Internet Explorer, Safari, or Chrome; only by Firefox and Opera. --FOo (talk) 18:23, 13 February 2011 (UTC)

SVG can also be animated, though many browsers have limited support and poor performance. We should draw attention to the important distinction between "the file format specification makes a feature possible" and "most web users will be able to use that feature." For example, GIF transparency had poor support in early web browsers; PNG support was totally lacking until just a few years ago. While I would argue that PNG is the best and most portable graphic format for "general web graphics", it has only become feasible recently as web browsers adopted support for it. The same can be said of SVG today: the variance in rendered SVG graphics between current browsers can be very large, so a web designer should use SVG with caution (even if it's a "better" vector format.) Nimur (talk) 21:05, 13 February 2011 (UTC)

Laptop

I used to have a "laptop" computer very similar to this with the orange monochrome screen (which I bought for £1 somewhere since it was so old and not working properly). I still have it, thought it's broken now. I have several questions;

1. Was / is it worth anything to a collector?
2. What technology was the screen made of? What gave it that orange glow?
3. Is it possible to emulate the same kind of orange monochrome display on Windows 7 using a standard modern screen, just for fun?

82.43.92.41 (talk) 18:04, 13 February 2011 (UTC)

These are called "amber" monitors, and our article Monochrome monitor discusses them and the amber glow; but I have never seen an amber monitor that displayed graphics like that; every monochrome monitor I have ever seen was hooked up to a IBM Monochrome Display Adapter or the like, which displayed text but was not capable of displaying graphics. (Side note, these adapters and monitors were coveted among programmers for a while in the 1990s after they had gone out of production, because it was a particularly easy way to output debug text and have a multiple monitor setup for doing so, at a time when this wasn't practical with 'normal' monitors.) Comet Tuttle (talk) 18:42, 13 February 2011 (UTC)

Comet Tuttle: I don't think you're right. I believe the monitor on that photo the OP linked to is an LCD monitor, so it has no relation to those amber monitors you mention. I suspect this because notebooks from that age usually came with LCD monitors, as CRT are too heavy and fragile, and also are thicker than would fit in that panel. I am puzzled on the amber color though, because the displays in the similar notebooks I've seen are plain white (or at least close to white).

As for your other question, I don't think the notebook would be valuable for collectors, but I can't be sure. – b_jonas 19:38, 13 February 2011 (UTC)

I agree, it's not a monochrome amber monitor. I have stricken the corresponding phrase above. Comet Tuttle (talk) 17:17, 14 February 2011 (UTC)

Thanks for the responses. The screen could absolutely display graphics; I remember drawing in paintbrush on Windows 3.11 with it. It also seemed to have two modes from what I remember - all orange with black lines and text (Windows 3.11) or all back with orange text (DOS mode) if that helps narrow it down 82.43.92.41 (talk) 20:14, 13 February 2011 (UTC)

I think it's a monochrome plasma display. -- BenRG (talk) 21:57, 13 February 2011 (UTC)

I agree with BenRG that the display is most likely a monochrome plasma display. Around 1990, high-end "portable" and compact computers used these displays because they were larger and had higher resolutions than what LCDs could provide at the time. LCD technology was pretty primitive back then compared to today, VGA resolution was not possible, for example, IIRC, and size was limited to under 10 inches. Since your "laptop" is similar to the Toshiba T3200SX, which was a business laptop featuring such a plasma display, and was marketed as being equivalent in most respects to a desktop business PC, its possible that a collector may be interested in it, even if its not usable (likely for spare parts - plasma displays are not exactly run-of-the-mill). Don't expect it to be worth lots of money, since computers depreciate pretty badly - folklore has it that a supercomputer site with a Cray that was bought for millions was worth a few thousand after it was decommissioned, and after failing to find someone to take it away, it was scrapped. In my experience, collectors are most interested in computers that are not run-of-the-mill, or if its something popular like an Amiga or Apple. Rilak (talk) 02:43, 14 February 2011 (UTC)

That brings back memories. I was using a Compaq Portable with plasma display to do AS/400 traces on twinax until a year ago. The Azure trace boards only worked in an ISA slot and no one made a similar product for any modern laptops. ---— Gadget850 (Ed) ^talk 16:44, 14 February 2011 (UTC)

Google Maps

I have an issue with this Google Map of Munich. Is there a way to directly notify Google that their maps are broken and can't tell me which road is which, or do I have to suffer through their help forums? Xenon54 (talk) 18:07, 13 February 2011 (UTC)

If you right-click on a Google map, there is a "report a problem" option at the bottom of the menu you get. This takes you to a small form that you can fill out with a description of the problem. I've used it in the past and gotten a reasonably prompt response -- make sure you give a clear and concise description of the problem and why it is important, though. Looie496 (talk) 18:37, 13 February 2011 (UTC)

The "Report a problem" link appears in certain countries -- Austria and Switzerland but not Germany (of course). I've tried doing it at the point where the A8 crosses the Austrian border, but I never even got the confirmation e-mail. Xenon54 (talk) 19:04, 13 February 2011 (UTC)

Strangely, I see no problems with the map provided by the OP. The large streets are labelled, the smaller streets are only labelled when you zoom in. The same goes for route numbering, though may city streets have no route number. Astronaut (talk) 03:04, 14 February 2011 (UTC)

If the problem is Google's rendering of the data, you'd need to go through Google's forums. If the underlying data is wrong (e.g. if roads are misidentified, or shown with incorrect connections) then that report would need to go to the supplier of the data. That's what the "report a problem" link does, but only for suppliers that Google knows how to communicate errors to; some don't. In this case it seems the map is supplied by TeleAtlas - they have their own report-a-problem app here. Note incidentally that Bing Maps for the same city uses map data from NAVTEQ instead, and so in addition to using Microsoft's rasteriser rather than Google's, it's different underlying data, and may suit your purposes better. If you've noticed just a very small imperfection, it could be a trap street; Open Street Map lists a large number of such features in TeleAtlas' database here. Finlay McWalter ☻ Talk 14:15, 14 February 2011 (UTC)

Forms on MS Word

Hi, I'm trying to make a form on MS Word and even found some characters that look like squares to use as checkboxes when I print them out. (Here it is: □) But they're too small. How do I make them bigger without messing up the line spacing? I tried putting 1.5 and even double spacing, but it keeps messing up the lines whenever I try to make them more than size 10pt. Thanks! --Jeevies (talk) 20:37, 13 February 2011 (UTC)

You could use a drawn square that you treat like an ordinary textual character (I don't know the English term for this. In Swedish it's called "I nivå med text".) --Andreas Rejbrand (talk) 20:57, 13 February 2011 (UTC)

I tried this first. Unfortunately, these are even more effective for creating imbalance between the line spacing. Also, when using the "in line with text setting" the box stays fixed upon the line of text when I need it to move slightly lower. The "tight" and the "square" settings create too much space in the sides when I want the box to be close to the word "yes" or the word "no". Thanks for replying quickly though! --Jeevies (talk) 21:24, 13 February 2011 (UTC)

I use empty text boxes for this type of application. It's not what they are intended to be used for, but small text boxes can be adjusted to any position and do not affect the flow of text when appropriately formatted. Once you've got one formatted, just copy it to save time (hold "ctrl" & drag), and hold the alt key to allow fine adjustment. One disadvantage is that (maybe just older?) versions of Word can get confused if you have too many such boxes on a page. I see many badly-designed forms using other techniques. Dbfirs 07:59, 14 February 2011 (UTC)

You could use [‾] - it's a left square bracket followed by an underlined overline followed by a right square bracket. Probably not the most technical solution, but it looks like a box to me. Rocketshiporion♫ 23:29, 15 February 2011 (UTC)

Editing a .docx (MS Word) document that has fields

I was given a Word document that I need to fill out, it has text input fields (the gray boxes you type in) but there are also some parts I need to edit directly that are not in fields. But I can't click on, or select, or in any way edit, the stuff not in the fields—it seems that documents with fields only let you edit the fields, not the other text. Does anyone know how to disable the fields in such documents, or enable editing the rest of the document, or just open the document in some way that allows normal editing? rʨanaɢ (talk) 23:45, 13 February 2011 (UTC)

You may be able to disable it by going to Tools -> Unprotect Document in Word. It may ask you for a password, and if you don't know that, you're going to have to guess. Or if you're really willing to think outside the box, you could contact the person/organization who generated the form. --Colapeninsula (talk) 11:14, 14 February 2011 (UTC)

Ah, found it, thanks. rʨanaɢ (talk) 15:35, 14 February 2011 (UTC)

No need to guess, from memory of last time I searched it's trivial to break Word read-only document protections (if the file is encrypted and you need a password to open and you don't have that password then obviously you're SOL). This isn't surprising, in the absence of a hardware protection layer that the content never leaves it should be expected, even more advanced protections like those for Bluray are usually broken to some extent (and there's always the analog hole). Of course doing so may violate the DMCA or any similar local laws although I'm not convinced guessing the password would be any better. Nil Einne (talk) 08:37, 16 February 2011 (UTC)