Wikipedia:Reference desk/Archives/Computing/2010 October 22

= October 22 =

tsql what is for keyword go?
if it's followed by a number >1 it's useful but otherwise.. t.i.a.--217.194.34.103 (talk) 09:28, 22 October 2010 (UTC)
 * http://social.msdn.microsoft.com/forums/en-US/transactsql/thread/b9813ad0-6053-4723-8516-87cf27ebcf35 --Sean 17:28, 22 October 2010 (UTC)

List of software licenses used in a particular Ubuntu/Debian installation
Hi, I'm aware that the package vrms will list all non-free/contrib software, but I'm looking for a tool to list all licenses of installed packages by name, including the free ones. After all, just because they're free, doesn't mean they all share the same distribution terms (think Public Domain vs. BSD vs. GPL2-only vs. GPL3, for example). Is there a way to compile such a list, other than by doing it manually? -- 78.43.71.155 (talk) 14:13, 22 October 2010 (UTC)


 * I don't think that info is captured in a well-formed way either in the .deb package format (it would be in the control file, but I don't see anything there) or in the standard file layout that's deterministically parseable. It's a standard feature of Debian packages that they create a file called /usr/share/doc/packagename/copyright, but that's human readable (to the extent that lawyers can be considered human), not a readily machine readable format. And I'm not sure that every package has such a copyright file, and that they always put it where they should (the Debian guys are pretty thorough, but are non-free packagers so careful?).  Beyond that, you can list all the installed packages with dpkg-query -l and for a given package list its constituent files with dpkg-query -L packagename, so (if you really needed this info) you could use this to examine every file in a given package, and then you're reduced to grepping the files for things that resemble copyright messages. -- Finlay McWalter ☻ Talk 14:40, 22 October 2010 (UTC)


 * Clarification: I know the licenses of those few non-free packages I have installed, in fact, I even have one system where vrms detects no non-free/contrib software. It's only the different free ones that are troubling me.
 * Sadly, comparing the output of dpkg --get-selections|wc -l (332 lines) and of find /usr/share/doc -iname "*copyright*"| wc -l (320 lines) shows that even the Debian guys didn't include a copyright notice with every package. :-( -- 78.43.71.155 (talk) 14:50, 22 October 2010 (UTC)


 * On further inspection, quite a few don't have a copyright file:
 * If I run dpkg-query -l | wc -l that reports 2934 (really 2934 minus a few lines for lines of header)
 * dpkg --get-selections doesn't produce a header ;-) -- 78.43.71.155 (talk) 15:19, 22 October 2010 (UTC)
 * If I run <tt>ls -R /usr/share/doc | grep -i copyright | wc -l</tt> that reports 2466 (they're almost all <tt>copyright</tt>, but there's a few oddbods with other copyrighty names, so I've included them)
 * So that would suggest about 16% of packages don't have a <tt>/usr/share/doc/packagename/copyright</tt> file. -- Finlay McWalter ☻ Talk 14:51, 22 October 2010 (UTC)
 * Further research shows that every package in the mainline Debian distribution is required to have a file named copyright in <tt>/usr/share/doc/packagename</tt>. The reason that they don't all show up during <tt>find /usr/share/doc -iname "*copyright*"</tt> is that some are actually symlinks - that is allowed for packages that use one of the more common licenses like BSD, GPLv2, GPLv3, etc., wich are stored in a common directory, and for packages that share the same copyright info with their required base-package. So basically one has to look at every file that the above-quoted find command spits out, but the result will be pretty much free of duplicates, thanks to find skipping over symlinks. -- 78.43.71.155 (talk) 15:47, 26 October 2010 (UTC)

Is a Storage Area Network head a Server?
Hello.

I want to know what exactly a Storage Area Network is - I am aware that a SAN contains HDDs which hold volumes which are attached to servers via logical unit numbers. My question is rather whether a SAN head is considered a server. And I refer only to the SAN head, not the DAS arrays connected to the SAN head, and I am also not referring to SAN switches or storage routers.

Best regards to everyone. Vickreman.Chettiar 14:33, 22 October 2010 (UTC)


 * A SAN device speaks a SAN protocol like FC or iSCSI and in essence pretends to be a big disk drive, so it should be considered a "storage device" and nothing else. I can't definitively say that some daft person won't consider all expensive enterprise electronic boxes to be "servers", but they shouldn't, and manufacturers to make both (like IBM, Sun/Oracle, and HP) don't. -- Finlay McWalter ☻ Talk 15:10, 22 October 2010 (UTC)


 * Just to clarify - since a NAS head, which serves files, is considered a file server; could a SAN head, which serves volumes (i.e. LUNs), be called a volume server? And as an aside, though it's just a matter of semantics, what is with the Area in Storage Area Network? Wouldn't it suffice to call it a storage network? I don't really understand the Area part... Vickreman.Chettiar  20:31, 22 October 2010 (UTC)


 * Is "SAN head" really a term in any use? If by that you mean a SAN device that aggregates a number of other SAN devices and presents them to a user on a single connection (something like a Brocade Fibre-Channel Switch), then I don't agree that it necessarily serves "volumes"; SAN is a block-level thing, so it serves blocks. Those blocks might just be direct-mapped from volumes in the downstream SAN devices, but such a device can remap and aggregate blocks (and devices, and connections) in more complicated ways. I think the A is there for symmetry with LAN, and to make it a word (rather than calling it an "SN"). -- Finlay McWalter ☻ Talk 20:43, 22 October 2010 (UTC)


 * For the record, the term SAN head is used by Hewlett-Packard. See the sixth paragraph of this Channel Register article by Ashlee Vance which quotes a HP Security Architect, which is what led me to begin with to figure a SAN head is considered a server, but I thought I'd check with the reference desk because I was unable to find any mention of SAN heads being classified as servers in the Wikipedia article on SANs. Vickreman.Chettiar  02:15, 23 October 2010 (UTC)

Is "ARC relationship" an Oracle term or generally accepted computer term?
Is "ARC relationship" an Oracle term or generally accepted computer science term? If it is Oracle only what is the standard name of this relationship. (If it is a general purpose term we should have an article on it!) -- Q Chris (talk) 15:00, 22 October 2010 (UTC)

Wipe out a USB stick
I've got a USB stick with some promotional material on it that resists deletion. It is within a partition disguised as virtual CD-ROM, which is read-only. The permissions cannot be changed. I also tried to remove it with a 3U removal tool and also deleting the whole thing with "sudo dd if=/dev/zero of=/dev/scd0". Everything without success. Does anyone have an idea of what can I do? Is there something which would reset the USB stick completely? (mtab output: /dev/scd0 /media/NEW iso9660 ro,nosuid,nodev,uhelper=hal,uid=1000,utf8 0 0 /dev/sdb1 /media/disk-1 vfat rw,nosuid,nodev,uhelper=hal,shortname=mixed,uid=1000,utf8,umask=077,flush 0 0)


 * Have you tried bringing it over to a Windows or Mac machine that doesn't understand the partition table, and have it format the device as a FAT32 or NTFS or ext3 (or whatever) volume? Comet Tuttle (talk) 15:41, 22 October 2010 (UTC)


 * The problem persists in a Windows machine, Windows also consider this thing to be a legit CD-ROM, which cannot be formatted... Mr.K. (talk) 15:47, 22 October 2010 (UTC)


 * What happens when you use disk partitioning software to delete the partition? Comet Tuttle (talk) 15:54, 22 October 2010 (UTC)


 * GParted does not see the partition that is a virtual CD-ROM. It sees only the other free partition.--Mr.K. (talk) 15:56, 22 October 2010 (UTC)


 * That's sort of awesome. My next step would be to use disk partitioning software on a foreign machine (meaning Windows or Mac) to try to delete the partition.  Or use some sort of embedded device, like a USB-stick-accepting camcorder, to try formatting the stick.  Comet Tuttle (talk) 16:05, 22 October 2010 (UTC)


 * Well, actually it was their intention to be awesome difficult to remove. Mr.K. (talk) 16:36, 22 October 2010 (UTC)


 * That won't help. The controller on a U3 device manufactures a virtual CD-ROM volume (and a virtual usb hub) from flash blocks on its device that it does not normally export as part of the normal usb-mass-storage device that it also presents. The protocol for manipulating this (to reserve some blocks and present them as a virtual CD, and to undo that) is proprietary and trade-secret; I'd imagine it consists of some vendor-specific commands sent to the virtual device hub.  The U3 section discusses a Windows program that the U3 people implemented which does the "remove" operation (I guess you had to pay them $$s to get the "create" software). -- Finlay McWalter ☻ Talk 16:42, 22 October 2010 (UTC)


 * (I never knew about this &mdash; thanks.) Comet Tuttle (talk) 17:10, 22 October 2010 (UTC)


 * I'm aware this is not the answer you are looking for, but: USB sticks are cheap. Send it back to whoever placed the advertisement junk on it, with a cover letter saying that you'd rather give it back than being forced to watch their promotional junk in order to use it, and that any promotional efffect they were hoping for was negative. If enough people do this, maybe they'll think a bit about their next ad campaign. -- Ferkelparade &pi; 16:03, 22 October 2010 (UTC)
 * It's not "promotional junk" but rather a common "feature" on a lot of flash drives. Shadowjams (talk) 09:21, 23 October 2010 (UTC)

That U3 thing is stored somewhere else on those keydrives, it's not stored on the accessible flash ram using fdisk. There's a provided tool by those manufacturers that will permanently remove it from the drive. I don't know if there's an open source version of the same thing, and I'm curious about where it's actually stored... but look at this link. Shadowjams (talk) 09:21, 23 October 2010 (UTC)
 * There is an open source version, see the Weblinks section of U3, which had already been mentioned above as U3. (RTFA ;-)) -- 78.43.71.155 (talk) 10:09, 23 October 2010 (UTC)
 * It isn't open source if you have to '$dollar signs' for it (RTFA ;-)). Shadowjams (talk) 10:17, 23 October 2010 (UTC)
 * Are we referring to the same thing? I presume 78 is referring to which while I don't know whether it will do what you need (or whether it works at all), is called open source by the article and is hosted on SourceForge who require things hosted there be open source. I don't quite understand your "$dollar signs" bit, but there's nothing stopping open source software from people charging for open source software under most definitions, for example the well known GPL doesn't stop it. However open source does usually at a minimum require the source code be available to anyone who owns the software and requests it, and without any additional payment except to cover the cost of distributing the source code. And people who use the software and obtain the source code are allowed to redistribute both for anyone to use without requiring permission or anyone requiring payment. So charging solely for those usually doesn't work very well (but offering additional services may) since other people may just redistribute it and your market may only ever be the first person to buy. Nil Einne (talk) 14:02, 23 October 2010 (UTC)
 * I prefer to be addressed by my last octet, you insensitive clod! - Just KIDDING :-D
 * You, as opposed to Shadowjams, did indeed understand what I was saying. Thanks for jumping in. :-) -- 78.43.71.155 (talk) 14:35, 23 October 2010 (UTC)

Can I change the font of a .pdf file?
Some authors have a really poor taste for fonts...--Mr.K. (talk) 15:43, 22 October 2010 (UTC)
 * What software do you have? Adobe Acrobat Professional can do lots of modifications (although whether it can change fonts I don't know) that other programs can't.  Nyttend (talk) 20:08, 22 October 2010 (UTC)
 * I'm pretty sure this is impossible in general, and would require grody hacking in the few special cases where it might be theoretically possible. Even if you could change the font, the spacing parameters would not change, so the result would probably look pretty bad. Looie496 (talk) 20:25, 22 October 2010 (UTC)
 * Adobe Acrobat Professional can change the font of text. You first select the text using the text touch-up tool. Then, you right-click on it and select "Properties." A dialog will appear with a font drop-down list.--Best Dog Ever (talk) 23:56, 22 October 2010 (UTC)

ubuntu help
i have ubuntu 10.10 .it takes an extremely long time for me to shut down the system or to log out ..why might this happen? —Preceding unsigned comment added by Metallicmania (talk • contribs) 17:09, 22 October 2010 (UTC)


 * Probably because some program or daemon is taking a long time to shut down. I'm not sure this will work, but try hitting the Esc key during the shutdown.  If I remember correctly, this will kick you into text mode, and you should be able to see a line saying what the OS is doing at that time.  (I'm sure somebody will correct me if I have this wrong.) Looie496 (talk) 18:11, 22 October 2010 (UTC)

im quite new with linux so i do dont think ill be able to figure out that stuff —Preceding unsigned comment added by Metallicmania (talk • contribs) 18:17, 22 October 2010 (UTC)
 * Basically what I'm suggesting is that you hit Esc while the computer is slowly shutting down, look at the bottom line of text which tells you what the computer is doing, and tell us what it says. Without that information it's pretty much impossible to guess what the problem might be. Looie496 (talk) 20:23, 22 October 2010 (UTC)

i think ive managed to resolve that but heres another query. i had vista on my lappie and there was a 100 gb c drive and a 2 gb d drive. i used the d drive for backing up stuff. when i changed to ubuntu the d drive is missing. the 100 GB in C drive is anailable as root but no idea where is the other location.is there any way i can find out where that 2 GB is ?Metallicmania (talk) 16:55, 23 October 2010 (UTC)
 * Installing Ubuntu required you to repartition the drive. If you don't see that old partition, it probably means you installed in a way that overwrote all the existing partitions.  It's possible to leave old partitions intact when installing, but that requires doing a custom install, and I'm guessing you didn't. Looie496 (talk) 18:44, 23 October 2010 (UTC)


 * The output of <tt>sudo fdisk -l</tt> (that's a lower-case L after the dash) might be helpful to us if we're to assist you with this issue. This is a command that you will have to type into a terminal window, and it will prompt you for your password. -- 78.43.71.155 (talk) 22:15, 23 October 2010 (UTC)

well this is the output i got Disk /dev/sda: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000e3713

Device Boot     Start         End      Blocks   Id  System /dev/sda1  *           1       14224   114251776   83  Linux /dev/sda2          14224       14594     2966529    5  Extended /dev/sda5          14224       14594     2966528   82  Linux swap / Solaris

Disk /dev/dm-0: 3037 MB, 3037724672 bytes 255 heads, 63 sectors/track, 369 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x80174800

Disk /dev/dm-0 doesn't contain a valid partition table

Metallicmania (talk) 11:21, 24 October 2010 (UTC)
 * Okay, I'm not sure if I would be allowed to re-format what you posted (this being the reason), so I'll just quote this with proper formatting:

Disk /dev/sda: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000e3713 Device Boot     Start         End      Blocks   Id  System /dev/sda1  *           1       14224   114251776   83  Linux /dev/sda2          14224       14594     2966529    5  Extended /dev/sda5          14224       14594     2966528   82  Linux swap / Solaris Disk /dev/dm-0: 3037 MB, 3037724672 bytes 255 heads, 63 sectors/track, 369 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x80174800 Disk /dev/dm-0 doesn't contain a valid partition table
 * Judging from this info, I'd say you re-partitioned your hard drive into one single, large partition usable for programs and data (/dev/sda1), and a smaller one (/dev/sda5 within the extended partition /dev/sda2, note the identical start and end cylinder numbers) for swapping.
 * I'm not sure, though, what /dev/dm-0 is supposed to be for, this could be some sort of onboard RAID controller providing a RAID1 or RAID0 with a capacity of roughly 3 Gigabytes. That seems pretty small for a RAID, though.
 * The output of <tt>sudo mount</tt> might be helpful for us telling you what it is used for. -- 78.43.71.155 (talk) 18:58, 24 October 2010 (UTC)

sorry bout the nonformatted output .this is the output of sudo mount

/dev/sda1 on / type ext4 (rw,errors=remount-ro,commit=0) proc on /proc type proc (rw,noexec,nosuid,nodev) none on /sys type sysfs (rw,noexec,nosuid,nodev) fusectl on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) none on /dev type devtmpfs (rw,mode=0755) none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) none on /dev/shm type tmpfs (rw,nosuid,nodev) none on /var/run type tmpfs (rw,nosuid,mode=0755) none on /var/lock type tmpfs (rw,noexec,nosuid,nodev) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) /home/raider/.Private on /home/raider type ecryptfs        (ecryptfs_sig=89229615e50cdc0e,ecryptfs_fnek_sig=5253ffe114df5b03,ecryptfs_cipher=aes,ecryptfs_key_bytes=16) gvfs-fuse-daemon on /home/raider/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=raider)

regardsMetallicmania (talk) 03:43, 25 October 2010 (UTC)


 * I don't see /dev/dm-0 in there, so it isn't mounted. What I can see is that your home directory is on an encrypted file system. I'm not sure if /dev/dm-0 has anything to do with that, and haven't used dm-style RAIDs, only md-style RAIDs, so I can't help you any further here. Maybe another Wikipedian knows if it's safe to attempt a mount of /dev/dm-0 to see if anything of the data you are looking for is stored there, or if it will interfere with your encrypted home directory. /dev/dm-0 is the most likely place where your data may be stored, if it is still stored somewhere at all. Judging from what I've seen so far, I'd expect your data to be gone, though - overwritten when you chose to perform a full-disk install of Linux. Sorry, I wish I had happier news for you. -- 78.43.71.155 (talk) 15:38, 26 October 2010 (UTC)

actually i really didnt mind loosing the data. but what about the disk space?is it lost? thanx a lot for your time and patienceMetallicmania (talk) 16:55, 26 October 2010 (UTC)
 * Quoted from your fdisk -l output, emphasis mine:

255 heads, 63 sectors/track, 14593 cylinders [...] /dev/sda1  *           1       14224   114251776   83  Linux [...] /dev/sda5          14224       14594     2966528   82  Linux swap / Solaris
 * So all of your disk space is put to good use, the large part (cylinders 1-14224) for storage, the smaller part (cylinders 14224-14594) for Swap space. -- 78.43.71.155 (talk) 22:59, 26 October 2010 (UTC)

Click here
Many pages on the Ohio Historical Society website, such as its profile of the Kirtland Temple, have a little note at the top: "Click here for a new search". Having read our click here article, I'm confused — in specific cases like this, why is "click here" a bad idea? For example, people printing offline won't be able to use a search page, no matter how well it's described. Nyttend (talk) 20:05, 22 October 2010 (UTC)


 * The "accessibility" section of click here says "Screen readers, used by the visually impaired, can read out only the hyperlinks on the page as a quick method of navigation." The other links on that page (those in the menu down at the bottom) read sensibly when presented like this ("calendar", "places", "about", etc.), but this link will just read "here", with no context. If the link text was "new search" then it would be fine. -- Finlay McWalter ☻ Talk 20:15, 22 October 2010 (UTC)
 * I saw that part, but I don't understand — what else would be expected to be read? The URL of the link target?  Nyttend (talk) 22:01, 22 October 2010 (UTC)
 * I don't understand what you don't understand :) As I said, if the text inside the A tag was "new search", that would make sense, but "here" doesn't.  You may have to ask a more detailed question if you need me to explain further. -- Finlay McWalter ☻ Talk 22:11, 22 October 2010 (UTC)
 * And while not as bad as the accessibility problem, if you printed that page (say to hand out to people on your historical society's trip to that building) it does look kinda daft having "click here" on a bit of paper. We're so used to seeing stuff like this because so many web authors take no care at all over what a printout of their site should look like (so it ends up as a screendump, full of useless navigation cruft that makes no sense on paper). Smart websites (of which Wikipedia is a good example) take the effort to strip screen-only content from the print (mostly using some deft CSS) so that the printout makes for a sensible free-standing paper document. -- Finlay McWalter ☻ Talk 20:19, 22 October 2010 (UTC)


 * I usually just highlight the content on a webpage which I want printed, click File and select Print Preview, then select the As selected on screen option, and hit Print. Sometimes I have to adjust the page size as well before hiiting Print, so that the edges of the webpage don't get cut off. At times the page margins also need to be adjusted (in Page Setup). Rocketshiporion ♫ 20:45, 22 October 2010 (UTC)

For example, if you consider HTML like this:

That would (on a reader that extracted the link texts for quick navigation) yield something logically like:


 * [here]
 * [click here now]
 * [click this link]
 * [speak the page text]

Whereas:

would yield
 * [newsletter]
 * [our DIY brain transplant kits]
 * [feedback about your brain transplant]
 * [speak the page text]

With a system like this, there is really no way for a user to know what a link [here] would do, short of reading through the entire text (which on a spoken interface is very tiresome). -- Finlay McWalter ☻ Talk 22:36, 22 October 2010 (UTC)


 * Note that a reader might also use the <tt>title</tt> attribute on the A tag, although those are so rarely used it's probably not worth the bother. -- Finlay McWalter ☻ Talk 22:43, 22 October 2010 (UTC)