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Linux Patch Clears the Air For Use of Microsoft's FAT Filesystem 272

Posted by ScuttleMonkey
from the anything-you-can-do-i-can-do-better dept.
Ars Technica is reporting that a new kernel patch may provide a workaround to allow use of Microsoft's FAT file system on Linux without paying licensing fees. "Andrew Tridgell, one of the lead developers behind the Samba project, published a patch last week that will alter the behavior of the Linux FAT implementation so that it will not generate both short and long filenames. In situations where the total filename fits within the 11-character limit, the filesystem will generate only a short name. When the filename exceeds that length, it will only generate a long name and will populate the short name value with 11 invalid characters so that it is ignored by the operating system."
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Linux Patch Clears the Air For Use of Microsoft's FAT Filesystem

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  • Maybe, maybe for something like a thumb drive, but on a hard drive?

    Or maybe I'm just scarred by microsoft's implementation of it...

    • The reason that FAT is still around has more to do with compatibility than any kind of technical merit. Pretty much every version of Windows supports FAT, and most other operating systems can use it as well. I think most "smart" vendors have figured out that if they use FAT for their devices (music players, cameras, GPS units) then pretty much anyone will be able to use them. That's why it's important to have FAT support in Linux, no one is saying that you have to use it on your / partition though. :-)

      • by croddy (659025) on Thursday July 02, 2009 @09:32AM (#28557561)

        when you're setting up your own filesystems, however... just use ntfs-3g and fs-driver. problems solved. just don't forget to use mke2fs -I 128

      • Re: (Score:3, Informative)

        by noname444 (1182107)

        Sometimes though, when you think you're being all smart, and you've formatted your USB-drive to FAT so you can use it easily in both Linux and windows. Then you start copying your DVD images or mkv / x264 movies onto the drive. 4 GB later: "out of disk space". "Huh? But this USB stick is like 16 GB! wait... DOH!"

        The 4 GB file size limit can be a bit of a hassle at times.

        • This limit is the only thing preventing me from using FAT32 on all of my hard drives. The system drive of my main PC is FAT32 (small files).
          Why would I want FAT32?
          1) It has a second copy of FAT*
          2) It is compatible with more operating systems.
          3) It does not support permissions**.

          * It is said, that NTFS is very reliable with its journal and things, however, there is only one copy of the MFT, so if your hard drive developed a bad sector there, you will lose some number of files. FAT has a second copy of the FA

      • by SharpFang (651121)

        And NTFS is not an alternative. If the mp3 player has a simple 8-bit CPU with 64K RAM, implementing NTFS is pretty much impossible, and anything else likely won't be readable from Windows. Besides, most common flash media (SD cards etc) use FAT,

        • by Tom9729 (1134127)

          Admittedly I don't know that much about file systems, but I think implementing any kind of journaling file system on a device like that (especially if it uses flash media) would be a bad idea. Going with the example of an mp3 player, 99% of the time the file system will only be used in a read-only way anyways so there really is no point in having anything fancy to keep track of writes in the event of an unexpected loss of power. :-)

    • FAT is needed to support embedded hardware that presents itself as a USB mass storage device to the host, or that has to talk to flash memory devices.

    • Be nice. (Score:4, Funny)

      by commodoresloat (172735) * on Thursday July 02, 2009 @11:28AM (#28559137)

      It's not FAT; it's just big-boned.

    • Re: (Score:3, Informative)

      by jonadab (583620)
      There are several reasons to want to use FAT:

      Multibooters store their files on FAT filesystems because they're supported by, in a word, everything. Want to share your files between FreeBSD, Linux, Windows, BeOS, and OS/2? FAT is your friend. I still keep most of my data on a vfat filesystem for this reason even though I haven't used Windows in aeons. When I switched from FreeBSD to Debian, I didn't have to worry about whether UFS support was included out of the box, or what package to install to get it,
  • by BumbaCLot (472046) on Thursday July 02, 2009 @09:07AM (#28557183)

    Is FAT used for anything other than USB drives?

    • Re: (Score:3, Informative)

      by daid303 (843777)
      To allow USB drives, cameras, SD cards and more to work out of the box under Linux. With this patch you can distribute Linux without the fear of Microsoft suing you (like the did with TomTom)
    • by Daniel_Staal (609844) <DStaal@usa.net> on Thursday July 02, 2009 @09:14AM (#28557289)

      Is FAT used for anything other than USB drives?

      You say that like that's a small thing.

    • Media players. Hard drives, in computers where there are multiple OS's. Industrial equipment controllers. I bet you even some satellites use FAT.

      It's ubiquitous because it's simple and until the NTFS drivers were fixed(read:not trashing your data), FAT was one of the only convenient formats for sharing data between Windows and Linux.

      • by ByOhTek (1181381)

        I found that for anything that could use NTFS, there is also an EXT2/EXT3 driver (that not only works better, but was more easily available earlier). It's just that a lot of Windows people don't think of EXT2.

        My rule of thumb:
        if the drive is under 120GB, I use FAT32, over, I use EXT2.

        • by Jesus_666 (702802)
          However, ext2 isn't that much better than FAT (no journal, for example) and the various Windows ext2 IFSes only work reasonably well in most circumstances - however, I did encounter situations where a certain Windows-IFS-volume combination wouldn't work reliably. Plus, NTFS has better compatibility than ext2 as there is no usable ext2 implementation for Mac OS.
      • by cowbutt (21077) on Thursday July 02, 2009 @09:52AM (#28557833) Journal
        Hopefully, soon, we can start using UDF [wikipedia.org] instead of FAT. Cross-OS compatibility is pretty much there, though FAT's support is still the most broad.
        • by Sancho (17056) *

          I don't see any indication that UDF supports journaling or anything else to maintain filesystem integrity--is that the case? If this is true, I don't see how it will be suitable for general filesystem use....

          • by cowbutt (21077)

            Um, FAT doesn't have those things either.

            My point was that unlike FAT, UDF isn't a proprietary standard, but is nearly as widely supported, making it suitable for the same classes of devices as which currently use FAT.

            • by Sancho (17056) *

              That's fair.

              But if we're going to move to something, it would be nice if that something were more advanced than FAT/UDF. I guess there are two perspectives:

              1) Things you'll do on your own. You can already format drives as UDF if you like, as long as you're only using systems which support it (lots of them do per your Wiki link.)

              2) Things that we want other people to do. This one is much harder--it's hard to get people to change. Are flash drive makers going to change from FAT to UDF? If so, wouldn't it

              • Re: (Score:3, Insightful)

                by FireFury03 (653718)

                If so, wouldn't it be nicer if they could change to something better?

                Depends what you mean by "better" - for many situations where FAT is used, you don;t *want* stuff like journalling because you're dealing with very low power embedded systems.

          • Re: (Score:3, Insightful)

            by Tetsujin (103070)

            I don't see any indication that UDF supports journaling or anything else to maintain filesystem integrity--is that the case? If this is true, I don't see how it will be suitable for general filesystem use....

            Yeah, but if it's to be used as a replacement for FAT...

        • by hitmark (640295)

          note however that anything older then vista do not have write support.

          but its a interesting thought non the less...

    • Re: (Score:3, Insightful)

      by FlyingBishop (1293238)

      Are you honestly that dense? That's like asking if CD drives are used for anything other than CDs.

      Flash drives have replaced floppies as the primary small rewritable data storage medium. Not supporting them is as egregious as not supporting DVDs, which incidentally have issues that are on sturdier legal ground.

    • Re: (Score:3, Insightful)

      by 91degrees (207121)
      Not much, but "USB Drives" covers a lot of devices. Most MP3 players and digital picture frames behave as USB drives, so do some satnav devices.
  • by causality (777677) on Thursday July 02, 2009 @09:07AM (#28557189)
    When I read this my first impression, though admittedly not an informed one, was "you mean people pay to use FAT?" I wish patents were more like trademarks, where if you don't vigorously defend them and instead let them go for a while, you lose them and they become public domain. Wouldn't that be nice, to get rid of all these situations as well as all of the "submarine patents" in one fell swoop?
    • by HungryHobo (1314109) on Thursday July 02, 2009 @09:12AM (#28557265)

      You get my support if you add in something about a requirement that it should be possible to build a working example of whatever you're patenting using the patent documentation(you know, so that patents actually serve their stated purpose).

    • Re: (Score:3, Insightful)

      by TheRaven64 (641858)
      Well, they're almost like that in the USA. You can't claim any damages that occurred between your becoming aware of infringement and filing suit. Fortunately, not many FAT patents are still valid. Patents last at most 20 years, so anything from the DOS days is gone. The relevant ones here were included with Windows 95. I presume MS filed them before releasing '95, possibly even before releasing the betas, so they should expire in the next few years.
      • by The Empiricist (854346) on Thursday July 02, 2009 @09:43AM (#28557699)

        You can't claim any damages that occurred between your becoming aware of infringement and filing suit.

        Sure you can. You can claim damages for damages that occurred between your becoming aware of infringement and filing suit. However, the other side can raise laches [wilmerhale.com] as a defense. If you delayed unreasonably in taking action, then the judge might bar your claim to earlier damages.

        What is reasonable and what is not? You can't look at the patent statute to find out, laches are a judicial remedy for inequitable conduct. Thus, you have to go through Federal Circuit cases to find cases that are most similar (and probably distinguishable given a particular set of facts).

        It would probably get very complicated in case where a third-party has allegedly infringed for some time, but the patent owner sued (or countersued) a new alleged infringer based on recent conduct. If the patent owner did not plan on suing the third-party, then why is unfair to wait until the recent conduct before suing the new alleged infringer?

    • by digitalunity (19107) <digitalunityNO@SPAMyahoo.com> on Thursday July 02, 2009 @09:16AM (#28557321) Homepage

      FAT is hardly a submarine patent. MS has sued MANY manufacturers over their use of FAT in electronic devices and most companies end up reaching a licensing agreement and the lawsuit is dropped.

      • by causality (777677) on Thursday July 02, 2009 @09:32AM (#28557569)

        FAT is hardly a submarine patent. MS has sued MANY manufacturers over their use of FAT in electronic devices and most companies end up reaching a licensing agreement and the lawsuit is dropped.

        Thank you for correcting my ignorance on this matter.

        Incidentally, the more I hear of things like this, the better I can understand why so many Europeans think it's absurd that the USA has software patents at all.

        • Re: (Score:3, Informative)

          by Jesus_666 (702802)
          There are plenty European software patents; they just don't have any legal backing.
        • Re: (Score:3, Insightful)

          Incidentally, the more I hear of things like this, the better I can understand why so many Europeans think it's absurd that the USA has software patents at all.

          Seriously i hope distros ship dumbed down "us versions" of packages to avoid stupid software patents, because i sure as hell don't give a flying fuck about infringing this patent in the UK. Once it's clear that software patents are hurting US companies, it wont take long for SIGs in congress to sort the problem out, and given the current economic climate bullying the EU to be as retarded as the US (in this respect, we sure as hell already are in other areas) isn't an option.

    • by Absolut187 (816431) on Thursday July 02, 2009 @09:18AM (#28557349) Homepage

      Actually, patents expire 20 years from the filing date. This means that (A) they only last 20 years (with some possible term extension of a few years) and (B) "submarine" patents are basically a thing of the past.

      Under the old law, patents expired 17 years from issue so you could keep an application going with continuations for 20 years at the PTO and still have a 17 year term. Now if you kept an app going that long, you would come out with zero term.

      • by PitaBred (632671)
        Now if the patent system could just figure out how to keep bullshit patents from getting approved in the first place, we'd be doing a lot better. 20 years is WAY too long to have any kind of process patent like One Click or FAT, not to mention a lot of them are relatively obvious extensions of current technology. Granted, the FAT32 long file name hack is pretty elegant and clever, and I can see why it may have deserved a patent, but now it's just an anticompetitive weapon rather than a technological differe
    • Re: (Score:2, Interesting)

      by Jurily (900488)

      When I read this my first impression, though admittedly not an informed one, was "you mean people pay to use FAT?"

      No they don't. At least, nobody I've ever heard of. Also, do US patents apply to imported software? Say, I download OpenBSD from [insert patent-free country here], then I use that to build my own product, am I infringing?

    • Re: (Score:3, Insightful)

      by mcgrew (92797)

      I wish copyrights were like patents and expired after 20 years instead of the unconstitutionally unlimited time thay do now. If patents were like trademarks they would be worse than copyright and never expire.

  • by Ex-Linux-Fanboy (1311235) on Thursday July 02, 2009 @09:13AM (#28557283) Homepage Journal

    As a long-time user of Linux who is currently using Microsoft Windows XP, the whole vfat (FAT with Win95 long file names) patent and how Microsoft has handled this patent makes me feel that maybe Microsoft is engaging in the same kind of monopolistic behavior that they engaged in when they destroyed Netscape in the 1990s.

    I'm sure people know about Microsoft's patent violation lawsuit against TomTom; if you don't the Wikipedia is your friend [wikipedia.org]. What a lot of people don't know is that Microsoft made some changes to Vista so that you can no longer easily use an unpatented filesystem like ext2 (Linux's 1990s file system which nicely enough is supported in Windows with a couple of different 3rd [ext2fsd.com] party drivers [fs-driver.org]).

    For me, it seems very suspicious that Microsoft made some changes to Vista that make it very difficult to use filesystems not patented by Microsoft around the same time they used licenses for their filesystems as a revenue source.

    I posted a blog about this back in March [blogspot.com] and to quote that blog entry:

    it can be shown, with Vista, that Microsoft removed compatibility for non-patented filesystems, forcing people to license Microsoft's patents, not because the patents are novel, but because the patented filesystems must be used for interoperability purposes

    • If the Windows Ext2 people updated the driver, theres nothing stopping you using Ext2 under Vista - I happily use the commercial HFS+ driver from MacDrive with no issues.

      So, in short, it sounds like an implementation issue.
      • by myxiplx (906307) on Thursday July 02, 2009 @09:37AM (#28557617)

        Actually, if you follow the links, it sounds like deliberate behaviour by Microsoft. If true Microsoft are asking for trouble with this. They change the behaviour for their own file system types, and generate an error for any other:

        Quoting from the fsdriver.org site:

        "Currently it is not possible to start a program on Vista if UAC is enabled and the program's executable is stored on an Ex2/Ext3 volume. An "invalid parameter" message box appears, but the program does not start.

        UAC is the feature of Vista that prompts the user to elevate the user privileges to administrator level when necessary. UAC is enabled by default. It is not recommended to disable it.

        The problem is caused by Vista's internals: There is some code that compares whether the name of the file system type is one of the following: "NTFS", "FAT", "FAT32", "CDFS", "NPFS", "MSFS" or "UDF". If there is a match, it is one of Microsoft's file system types and a lot of code is skipped in the Multiple UNC Provider (MUP) implementation of Vista. If the file system type is a third-party type, for example "Ext2", some code runs in the MUP of Vista that always generates an ERROR_INVALID_PARAMETER error status code due to a bug of Vista."

        source: http://www.fs-driver.org/relnotes.html [fs-driver.org]

        • by sjames (1099)

          Sounds like what they did with DR-DOS back in the Win 3.1 days. Truly, MS is deeply resistant to reform. They keep pulling the same crap year after year.

          I'm betting the "unfortunate bug" is also tagged with "won't fix".

    • Re: (Score:3, Interesting)

      by AceJohnny (253840)

      I was initially skeptical because of your abusive use of "unpatented" all over the place, as if this is solely about patents. You don't provide any clear links here, but 2 clicks away, I found this [fs-driver.org]:

      The problem is caused by Vista's internals: There is some code that compares whether the name of the file system type is one of the following: "NTFS", "FAT", "FAT32", "CDFS", "NPFS", "MSFS" or "UDF". If there is a match, it is one of Microsoft's file system types and a lot of code is skipped in the Multiple UNC P

      • by FauxPasIII (75900)

        > Bug or on purpose? Who knows.

        When in doubt, always remember Bart's Second Law:

        Any time a person or entity makes a "mistake" that puts extra money (or power) in their pocket, expect them to make that "mistake" again and again and again.

        http://www.bartcop.com/bartslaw.htm [bartcop.com]

    • by MojoRilla (591502) on Thursday July 02, 2009 @09:38AM (#28557627)
      The bottom line is that Microsoft is using its monopoly position as an operating system vendor to force third parties to license trivial but patented VFAT technology that is only useful for interoperability.

      If that isn't abuse of their monopoly, I don't know what is.
      • "If that isn't abuse of their monopoly, I don't know what is."

        Perhaps you don't know what it is. If MS denied third parties a license, then you could make the case that there are abusing their position, but enforcing your patents and requiring a license fee, isn't abuse.

        • by sjames (1099)

          When it's coupled with a scheme to prevent patent-free filesystems from working on Windows, it certainly IS an abuse.

          • Windows has its file systems which isn't an abuse. I don't know whether there's an API for installing a foreign file system, but the lack of one isn't abuse either.

            If you wanted to implement a file system on top of Windows, there's nothing to prevent you from doing so. It's not as if Windows uses AI to scan your code and displays an error message like "You are running a patent-free filesystem, application will close".

            • by Tetsujin (103070)

              Windows has its file systems which isn't an abuse. I don't know whether there's an API for installing a foreign file system, but the lack of one isn't abuse either.

              If you wanted to implement a file system on top of Windows, there's nothing to prevent you from doing so. It's not as if Windows uses AI to scan your code and displays an error message like "You are running a patent-free filesystem, application will close".

              I guess you haven't checked out the various links to the "Ext2 IFS for Windows: Release Notes"...

              Basically it seems that, in Vista, the ability to execute programs stored on a third-party filesystem was broken. They didn't need to use "AI" to find out if a third-party filesystem was being run, they simply used a string comparison on the filesystem type.

            • by sjames (1099)

              No, they just look to see if it's an MS provided filesystem. If not, the application will never be allowed to run.

              Just like what they did w/ DR-DOS and Windows 3.1.

    • by croddy (659025) on Thursday July 02, 2009 @09:41AM (#28557669)

      ext2fsd and fs-driver both work on vista. and they'll both mount my ext3 filesystems, as long as i formatted them with the right inode size.

      the issue you (eventually) link to basically says that all ext2/3 filesystems mounted on vista are the equivalent of noexec. i don't think it is accurate to describe that as a significant issue. i don't know many people who keep substantial quantities of windows executables on their linux drives. the permissions system on ext2/3 is totally wrong for windows anyway, so you'd never use it for, say, %ProgramFiles% or %SystemRoot%.

      do not disable UAC.

      the problem i have with vista's driver support is that on amd64 it requires them to be cryptographically signed by some sort of extortion outfit, or i have to press F8 F8 F8 F8 F8 F8 F8 F8 F8 F8 F8 up up enter every time i boot the system in order to get it to load the drivers i need.

      • by sjames (1099) on Thursday July 02, 2009 @10:35AM (#28558329) Homepage

        Ext2/3 supports the use of xattrs that are perfectly adequate for storing ACLs and other such. In fact, however rarely it is used, that's how ACLs are supported in Linux. xattrs are also used to store SELinux data.

        It is true enough that there probably aren't many windows .exes stored on ext2 other than for backup or sneakernet, but it does represent a needless limitation that appears to exist purely as an attempt to force 3rd parties to use MS's patented junk.

    • by abigsmurf (919188)
      File systems are a core part of an OS. The Internet Explorer rulings only apply because the courts ruled that was a separate product. When you buy Windows, part of the cost is going towards the licences for them. If there was ever a court ruling saying they had to support rival file systems on their own OS it would open the floodgates for insane amounts of nuisance law suits from companies competing again ones with large market shares.
  • The patents (Score:5, Informative)

    by Absolut187 (816431) on Thursday July 02, 2009 @09:15AM (#28557299) Homepage

    Two of the patents are:
    USPN 5,579,517 [uspto.gov] and USPN 5,758,352 [uspto.gov]

    Claim 1 of the '517 patent reads:

    1. In a computer system having a processor running an operating system and a memory means storing the operating system, a method comprising the computer-implemented steps of:

    (a) storing in the memory means a first directory entry for a file wherein the first directory entry holds a short filename for the file, said short filename including at most a maximum number of characters that is permissible by the operating system;

    (b) storing in the memory means a second directory entry for a the file wherein the second directory entry holds a long filename for the file and wherein the second directory entry includes an attributes field which may be set to make the second directory entry invisible to the operating system and the step of storing the second directory entry further comprises the step of setting the attributes field so that the second directory entry is invisible to the operating system, said long filename including more than the maximum number of characters that is permissible by the operating system; and

    (c) accessing the first directory entry with the operating system.

    Claim 1 of the '352 patent reads:

    1. In a computer system having a storage, a directory service for accessing directory entries and a file system that uses the directory entries to access files, a method, comprising the computer-implemented steps of:

    (a) creating a first directory entry for a file wherein the first directory holds a short filename for the file and the location of the file;

    (b) creating a second directory entry for the file wherein the second directory entry holds at least one portion of a long filename having a fixed number of characters and a signature that identifies that the second directory entry holds a first portion of the long filename;

    (c) storing the first directory entry and the second directory entry on the storage among the directory entries used by the directory service; (d) accessing the second directory entry by the directory service to access the file; and (e) creating and storing in the storage a sequence of at least one additional directory entry for holding a next sequential portion of the long filename.

    It will be interesting to see what the Supreme Court has to say about the scope of patent-eligible subject matter in the upcoming Bilski case. It will probably be a year or two before we get a decision.
    http://www.patentlyo.com/patent/2009/06/bilski.html [patentlyo.com]

  • So when the file can fit in 8.3, it is saved as such, and when it can't, the long file name is saved in the directory, but a corresponding short name is created with a bunch of bogus random garbage. TFA doesn't explain what happens with mixed-case 8.3 filenames (VFAT long names would be case-preserving, but it may not be a great idea to use mixed-case in 8.3 directory entries), and that would be interesting to know.

    The only real problem I can see if you name stuff with long names (or maybe use mixed-case s

  • by wardk (3037) on Thursday July 02, 2009 @09:24AM (#28557449) Journal

    they want their obsolete file system back

    • Sure, FAT is obsolete, I wouldn't want it as my primary partition, but lets say I want to have a small partition to read/write on to store a few music files that are readable across OSes. I would more than likely have to use FAT because the others don't work with all OSes.
    • Re: (Score:3, Informative)

      by Jesus_666 (702802)
      Come up with a replacement that allows reading and writing without any FS-specific actions to be taken by the user, has low administration overhead and has native first-class support by every operating system and we can talk about FAT being obsolete. Right now FAT32 is the most modern, most advanced file system in its class (the class of high-compatibility general-purpose filesystems, which consists entirely of FAT16 and FAT32).
  • by phoxix (161744) on Thursday July 02, 2009 @09:28AM (#28557515)
    One has to wonder if these are Microsoft's actions around something as simple as VFAT, why the f*** would we trust them with C# ??

    What am I missing here ?

    Will Groklaw one day be reporting about MSFT v. SPI ?

  • It shouldn't have had to be done.
    This patent really smells of anti-trust to me since the only good reason to use it is for compatibility with Microsoft's products.

  • we stop using proprietary filesystems from microsoft, stop making them less lethal to linux, and start making it easier for normal everyday people to stop using them too! a sanitizing program for thumb drives that converts your fat data to EXT perhaps?
    • MS made some changes to Vista to make it very very hard for a third party program to read/write to any non-MS partition. So who is going to make a cheap flash drive that only works on Linux, BSD and OS X? I would imagine the answer would be not very many.
    • Re: (Score:3, Insightful)

      by pentalive (449155)

      wouldn't the sanitizing program stand in violation of the patent?

      • nope it merely takes a raw data-dump of a pen-drive and converts tables in that data dump to inode addresses according to an algorithm of its choosing, in no way does it deal with any of your so called "filesystems"!

    • by Jesus_666 (702802)
      That will work exactly when Microsoft decides to make ext* a first-class filesystem for Windows and Apple decides to do the same for OS X. Until then you can use ext* all you want; I'll use a filesystem that means people besides me can mount my thumb drive.
  • by asdf7890 (1518587) on Thursday July 02, 2009 @09:53AM (#28557847)
    This sounds dangerous to me. What if someone uses this to write to an SSD card that they plug into some cheap portable device (a media player for example) that doesn't implement the "standard" properly and gets confused by the data in the short filename when a long one is present? Or refuses to read half the files because it only likes short names (some cheap Chinese import MP3 players just use the short filename in displays) and half the files have names too long? The user won't blame their crap cheap little portable device they paid $3 for on eBay, they'll blame that there Linux thing because their copy of Windows can write things so the player understands.
  • by peppepz (1311345) on Thursday July 02, 2009 @10:21AM (#28558151)
    I use FAT on my usb keys only because I want to be able to use them from Windows machines.
    But in Windows Vista+ you can also format USB flash drives to UDF (you’ll have to use the command line FORMAT tool, the GUI frontend won’t show UDF as an option).
    When formatted in UDF, the drive’s performance improves dramatically: on my usb key, untarring the linux kernel and then deleting it changed from taking a few hours to taking a few minutes.
    UDF can be read/written under Linux and, unlike NTFS, it natively supports all UNIX features (including extended attributes), so for example you could boot Linux straight from a Windows-accessible USB drive without creating ext3 images on it, and without using userspace file system drivers.
    So it could be a nice solution for Linux/Windows interoperability... but sadly Windows stops liking UDF file systems if Linux creates files on them (I don’t know what exactly makes Windows upset; when it happens, Windows’ CHKDSK says the file system is OK).
  • Bad idea (Score:4, Insightful)

    by marcansoft (727665) <[moc.tfosnacram] [ta] [rotceh]> on Thursday July 02, 2009 @10:22AM (#28558169) Homepage

    This will break the myriad of read-only implementations out there that only use short names, which is a lot more than you'd think. This means this can't be enabled by default on your average Linux.

    It might help TomTom and the like, but it's not a cure for the patented portions of FAT. It's just a hack that might help some specific implementors. Kudos to the kernel developers for doing their best, but the real solution is to get the bogus patents invalidated.

    • Re: (Score:3, Insightful)

      by metamatic (202216)

      It only breaks implementations that only support short names, if you write files with long names to the filesystem and rely on them ending up with LONGNA~1 type filenames.

      If your filenames are all 8.3 and you write them to a disk for your implementation that only understands 8.3, everything still works. If your filenames are long, you write them to a disk for your implementation that only understands 8.3, but you don't make any assumptions about what the filenames will be when converted to 8.3, everything s

  • Let's suppose a new version of Windows started checking whether files with long filenames also had short filenames - and when encountering such a file, popped up a dialog saying "your filesystem may be corrupt. Please run scandisk" or whatever.... Wouldn't that be fun?

  • by arkarumba (763047) on Thursday July 02, 2009 @11:37AM (#28559293) Journal

    (SFNDE = Short File Name Directory Entry)
    .
    Regarding the patent filed in 1993.
    .
    It seems that the aim is to implement a "different idea" than that expressed in Figure 6b. (free rego at freepatentsonline to see original PDF with figures)
    .
    What about all the references to "short filename including at most a maximum NUMBER OF CHARACTERS THAT IS PERMISSIBLE BY THE OPERATING SYSTEM."
    Is the Linux Operating System limited to a only of 8.3 characters? To that effect, why does this patent apply to Linux at all?
    .
    I can't quite remember my history, but weren't long filenames (LFN) introduced with Windows 95 in 1995? Wasn't Win95 just a GUI layer on top of DOS and so bound by the filename length contraint of the DOS "OPERATING SYSTEM"? Wasn't it actually the Win95 GUI that interpreted and displayed the LFN?
    Isn't Linux access to FAT different?
    .
    Even though the FAT filesystem was limited to 8.3 characters, don't you think that DOS was "hardcoded" to 8.3 characters. Thus it was a constraint of the "Operating System" that this patent was addressing. The Linux situation seems completely different. Linux does not have this constraint, thus the Linux "idea" for implemeting dual directory entries is different than the "idea" for Windows GUI on DOS as expressed in the given patent - ie thus the "idea" for Linux is compatability, whereas the "idea" for Windows was to get around the 8.3 constraint.
    .
    Fig 2 shows LFNDE alongside SFNDE. Is that required technically for compatability, or can they be stored apart?
    Alternatively ONLY create long filename, then have some sweeper task come along and create the short filenames from the long ones.
    .
    It talks about only creating a LFN when it is longer than 8.3.
    Well then, create a LFNDE "EVERY TIME".
    .
    The patent says "At a minimum, a short filename will be created."
    Have linux do it differently, at a minimum create both a long and a short filename.
    .
    The patent describes using "both SFN APIs and LFN APIs".
    Does linux have both or does it do it "differently" with just LFN APIs?

    • Re: (Score:3, Insightful)

      by cdrguru (88047)

      Uh, no.

      The FAT file system stores 11 characters per file name in the directory entry, period. By convention, these are allocated to eight file name characters and three extension charcters. These are stored as 8-bit bytes.

      No, Windows 95 is not a GUI on DOS. All Windows versions before 95 were that. Windows 95 introduced several new concepts such as the VxD and a different virtualization structure. Yes, Windows 95 through Windows Me had a primarily 16-bit kernel and a few 32-bit extensions and much of t

  • by DaveV1.0 (203135) on Thursday July 02, 2009 @12:02PM (#28559785) Journal

    It looks like someone has forgotten that what is good for one's self is not necessarily good for everyone else.

    The Linux Foundation says that the best solution at this point is for vendors to ditch FAT and come up with a new vendor-neutral format that can be used without having to pay licensing fees.

    An industry-wide shift towards an open royalty-free format in the hardware space could potentially liberate device makers from this dependence on Microsoft's encumbered technology.

    It may be the best solution for Linux advocates, but it is probably not the best solution for the device manufacturers. 90% of their market uses Windows. If the manufacturers moved to a "new vendor-neutral format", they would break the automatic compatibility with 90% of their market and they would also have to ship driver disks to install the drivers needed to read and write the new format with every device. This would increase the cost of manufacturing and packaging as well as make it harder to use the devices.

    Perhaps Linux supporters should stop being so self-centered and start thinking of the larger picture before making such statements.

  • by spitzak (4019) on Thursday July 02, 2009 @12:07PM (#28559917) Homepage

    The patent is (or should not be) on the obvious parts of the system. There is a clever thing in VFAT, in that they use hidden "volume label" directory entries to store the long name, and this work-around does not change that.

    This is not just long filenames (unless the patent system is broken much worse than anybody thinks). It is blatently obvious how to add long filename support to a file system that has short filenames. However the "obvious" solution would be to use a single hidden file to store all the names. Microsoft chose another solution, and for a good reason (their solution has an advantage that if an "old" system deletes all the files in a directory, the directory looks empty. A hidden file would either be too easy to delete by accident or would be "locked" and thus the old system would be unable to empty the directory).

    It is also blatently obvious that an 8.3 replacement filename must be made for the file, so that can't be patented. They may have patented the pattern but I'm fairly certain that any unique pattern of characters with the same extension would not break any software (they could have made a system where "part" of the long filename is stored in the 8.3 name, but they did not because they were probably worried about handling collisions of these short names, or just rushed with their implementation).

    So I really don't see how this works around the actually patentable part of this, since the use of volume label directory entries is still being done.

    It also appears that *reading* the long filenames is allowed without a license. So anybody can read these disks.

    My suggestion would be to use a new method to store the long names. Users of Windows looking at the disk would see only the short names. People say that the users will blame Linux for that, but they are seriously underestimating the stupidity of users, they will blame the Windows machine, since when they put the disk back in the Linux machine the filenames work!

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