[HN Gopher] BigFAT - Backward compatible FAT extension for unlim...
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       BigFAT - Backward compatible FAT extension for unlimited file size
        
       Author : FrankSansC
       Score  : 170 points
       Date   : 2022-09-07 11:17 UTC (11 hours ago)
        
 (HTM) web link (www.segger.com)
 (TXT) w3m dump (www.segger.com)
        
       | kmeisthax wrote:
       | >Unfortunately, exFAT has been adopted by the SD Association as
       | the default file system for SDXC cards larger than 32 GB. In our
       | view, this should never have happened, as it forces anyone who
       | wants to access SDXC cards to get a license from Microsoft,
       | basically making this a field owned by Microsoft.
       | 
       | So, this is a bit of a cultural/perception gap between FOSS
       | developers and standards bodies. Most standards bodies have a
       | patent policy of "as long as all the standards-essential patents
       | are licensable for a uniform fee, we're good". Convincing patent
       | holders to not extract royalties from their patents for the sake
       | of easing the lives of FOSS implementers is much, much harder[0].
       | 
       | Microsoft isn't even the only SEP holder for SD, and the standard
       | makes no attempt at being a royalty-free standard. In fact, early
       | SD standards were NDA'd[1] and prohibited FOSS implementation _at
       | all_.
       | 
       | [0] In fact, so hard that the EU has a conspiracy theory that
       | Google/AOM bullied a patent holder into doing this
       | 
       | [1] Remember, SD cards were basically MMC with primitive DRM
        
       | CodesInChaos wrote:
       | Are the exFAT patents still a problem nowadays?
       | 
       | > exFAT was a proprietary file system until 2019, when Microsoft
       | released the specification and allowed OIN members to use their
       | patents.
       | 
       | https://en.wikipedia.org/wiki/ExFAT#Legal_status
        
         | NotYourLawyer wrote:
         | > We also support the eventual inclusion of a Linux kernel with
         | exFAT support in a future revision of the Open Invention
         | Network's Linux System Definition, where, once accepted, the
         | code will benefit from the defensive patent commitments of
         | OIN's 3040+ members and licensees.
         | 
         | I don't know exactly what that means. But it sounds like
         | something different from "we hereby grant everybody a license
         | to any and all exFAT patents."
        
           | [deleted]
        
         | loeg wrote:
         | Good for OIN, but it doesn't help non-Linux systems.
        
         | slavik81 wrote:
         | The patent will also expire in 2027 [1]. We can look forward to
         | it being entirely unencumbered at that point.
         | 
         | https://patents.google.com/patent/US20090164440?oq=US2009164...
        
           | ksec wrote:
           | I sometimes wonder if companies could choose to expire their
           | patents earlier. Especially in cases when there are little to
           | no strategic value to uphold them, but lots of potential
           | value to unlock when they are gone.
        
       | [deleted]
        
       | tzahifadida wrote:
       | Looks good. Keep at it!
        
       | ninefathom wrote:
       | I'm a bit puzzled as to how split files with name standardization
       | is an "extension." It seems to me that SEGGER is simply proposing
       | a de facto file naming convention, and offering a few free tools
       | (including a few abstraction drivers) to encourage adoption.
       | 
       | Can somebody fill me in, here- where's the value in what SEGGER
       | is proposing, as opposed to what the entire IT community has
       | already been doing for decades?
        
         | didgetmaster wrote:
         | I think many programmers have used file splitting technology at
         | the application level for decades. I know I wrote one for a
         | backup utility (Drive Image) back in the 90s that would split
         | the output files into smaller pieces for transfer to removable
         | media (floppies, Zip drives, CDs, DVDs, etc.).
         | 
         | It sounds like BigFat is an extension that takes away the need
         | to do this at the application level. The code does all the
         | splitting and merging for you so you can write a program that
         | acts like the file is on a file system that supports files >
         | 4GB.
        
         | jaclaz wrote:
         | I had the same impression, I cannot see how it is different
         | from the tools that allow file splitting (for later archiving
         | on floppies. CD's, DVD's, etc.) that exist since forever,
         | when/if implemented in OS filesystem drivers then it will be
         | more "transparent", but until then it seems to me not different
         | from multi-part archives, such as rar or similar.
         | 
         | If I may it would make more sense (to me at least) to use a
         | directory and have a descriptor file, not entirely unlike
         | multi-part vmdk's are implemented.
        
           | noAnswer wrote:
           | Using split, cat or rar doesn't allow random access.
        
             | jaclaz wrote:
             | But also this "extension" doesn't seem like allowing it.
             | 
             | On the contrary (but it is a specific "niche" case) the
             | mentioned vmdk split format allows to mount the vmdk same
             | as monolithic, with full random access.
        
               | noAnswer wrote:
               | Of course it does. "BigFAT allows random read and write
               | access to any file, even if larger than 4GB, as required
               | by databases."
        
               | jaclaz wrote:
               | I think we are talking of two different things, I was
               | talking of the extension document/specification, that one
               | seems to bring no particular innovation.
               | 
               | The actual implementation (by SEGGER or by someone else):
               | 
               | >Q: Can I implement BigFAT myself?
               | 
               | >A: Absolutely. BigFAT is a specification made available
               | by SEGGER. Anybody is free to write a piece of software
               | implementing it. No fees, no royalties, no headaches. You
               | do not even have to let SEGGER or anybody else know.
               | 
               | is what may allow that (random access), this
               | implementation would be useful if - instead of a
               | "feature" of a given app/program - it would be
               | implemented as a filesystem driver of sorts.
        
         | netsharc wrote:
         | Edit: I guess my first look is wrong, on second look, it
         | appears it needs their own filesystem driver. If the hack as I
         | wrote would've worked, it would've been very clever, and
         | dangerous...
         | 
         | > de facto file naming convention
         | 
         | From a first look, like it's using Microsoft's own hack of long
         | file names[1] to create file entries that look like they belong
         | to 1 file. A file that has a long file name (more than the 8+3
         | character limit) is actually several file entries, but they're
         | empty files. Seems like the tool is creating non-empty files
         | instead, that Windows is chaining together as one.
         | 
         | [1]
         | https://en.wikipedia.org/wiki/Design_of_the_FAT_file_system#...
        
         | mort96 wrote:
         | Well, if we view FAT32 + this name convention as a new
         | filesystem, then filesystem drivers could let you transparently
         | operate on files bigger than 4GB (GiB?) and take care of the
         | splitting for you. FAT32 + this convention would essentially
         | become a filesystem which supports files up to around 4TB. You
         | wouldn't have to make the choice between the patent-encumbered
         | exFAT and the open but limited FAT32.
        
       | tumetab1 wrote:
       | The thing missing on the page is some kind of performance
       | benchmark which I would love to read/see.
        
       | mikece wrote:
       | > Why not exFAT... Microsoft owns several patents, and anyone who
       | implements or uses exFAT technology needs Microsoft's permission,
       | which typically also includes paying fees to Microsoft.
       | 
       | While BigFAT not being encumbered by any patents is a good thing,
       | the camera industry have pretty much standardized on exFAT for
       | their removable file storage format. Something I'm curious about
       | is how a 5GB video file (quite common and actually on the smaller
       | size for 4K and 8K recording sessions) is written and accessed
       | between the two file systems. BigFAT says that the file would be
       | written in 4GB chunks; is there something similar happening with
       | exFAT or is the file "one chunk?" (Apologies if I have the terms
       | wrong -- I'm not a filesystem expert.) The author laments that
       | the exFAT format has been adopted for SDXC cards but given who
       | all is in this group and what their use cases are I can discount
       | "because Microsoft strong-armed them" as a reason for them
       | selecting it.
        
         | cmurf wrote:
         | The industry could have used UDF. Derived from ISO 9660, but it
         | supports read-write random access storage.
         | 
         | I'm guessing they didn't if FAT12/16/32->exFAT driver changes
         | are comparatively simple, and/or results in a smaller code base
         | to support FAT32 and exFAT on the same device (e.g. a camera).
        
           | mikece wrote:
           | And on a camera that costs anywhere from USD$1000 to USD$6500
           | does the cost of an exFAT license really matter?
        
             | vetinari wrote:
             | Yes, it does.
             | 
             | If you manufacture 100K of them, and save 10 dollars on
             | every piece, you got an extra million in savings.
        
               | xxpor wrote:
               | From the wiki, my understanding is the licence is $0.25 a
               | unit, not $10?
        
               | vetinari wrote:
               | It was a number to illustrate a point, not exact figure
               | for this specific case.
               | 
               | Yes, the manufacturers will go great lengths to minimize
               | variable costs. If they can shave $0.25, they will. At
               | volumes, it matters.
        
         | lathiat wrote:
         | ExFAT is not limited to a 4GB maximum file size. It just has
         | more than 4GB in the file.
         | 
         | I guess 4GB seemed like a reasonable limit when FAT32 was
         | designed.
         | 
         | Most likely FAT32 has a 32bit number for file size and ExFAT
         | presumably has either a 64bit one or stores file size in some
         | format other than bytes.
        
           | creshal wrote:
           | > I guess 4GB seemed like a reasonable limit when FAT32 was
           | designed.
           | 
           | FAT32 was always seen as stop-gap measure for low-end
           | consumer hardware when introduced in 1996; NTFS was
           | introduced 3 years prior to handle terabyte-scale data for
           | enterprise users.
           | 
           | > Most likely FAT32 has a 32bit number for file size and
           | ExFAT presumably has either a 64bit one
           | 
           | Correct.
        
         | zinekeller wrote:
         | I actually am disappointed that Microsoft has a chance to fix
         | some inherent problems with FAT but didn't, even considering
         | the main use case of a simple FS. Notably, it still has the
         | notorious year 2100 bug (or 2108 bug, depending on the
         | implementation), the metadata is weird and not at all
         | straightforward, it's basically just extending FAT32 and some
         | minor updates since Unicode and UTC are now here.
        
       | sampa wrote:
       | If only they released it back when exFAT was released. Now it has
       | no future.
        
       | mort96 wrote:
       | I like the idea. Making it backwards compatible with FAT means
       | that, in principle, regular FAT filesystem implementations could
       | be transparently changed to support big fat files (hehe)
       | transparently.
       | 
       | However, reading the spec, it doesn't look fully backwards
       | compatible? It seems like there are file structures which are
       | possible to represent in FAT which aren't possible to represent
       | in BigFAT. In FAT, I could have a 4GB-128kB size file called
       | "hello.txt", and next to it, a file called
       | "hello.txt.000.BigFAT". A FAT filesystem will show this as
       | intended, but a BigFAT implementation will show it as one file'
       | "hello.txt". That makes this a breaking change.
       | 
       | I would kind of have hoped that they had found an unused but
       | always-zero bit in some header which could be repurposed to
       | identify whether a file has a continuation or not, or some other
       | clever way of ensuring that you can represent all legal FAT32
       | file structures.
        
         | NelsonMinar wrote:
         | What FAT32 filesystem in the real world has a file named
         | "foo.000.BigFAT" on it?
        
           | londons_explore wrote:
           | I can imagine that if bigfat is successful, such files will
           | start to exist.
           | 
           | Imagine someone takes a bigfat drive and puts it in a non-
           | bigfat capable machine, then zips up a directory and
           | publishes it.
           | 
           | When that directory is unzipped on a bigfat machine, should
           | the bigfat files be re-joined, or should they show as
           | separate files? One breaks the OS file API and the unzip
           | program might crash/fail, while the other leads to the
           | application trying to create filenames which can't exist in
           | the filesystem.
        
             | jonny_eh wrote:
             | > should the bigfat files be re-joined, or should they show
             | as separate files
             | 
             | They're only "rejoined" by the BigFAT compatible filesystem
             | driver on access. By running such a driver, you're agreeing
             | that such files should "appear" as one.
        
               | mort96 wrote:
               | Hey, notice that you're suggesting that BigFAT should be
               | disabled by default here; you think the user should have
               | to choose to be running a driver with BigFAT-support.
               | Maybe reflect on whether that's a desirable situation, or
               | if it would've been preferable if the feature could've
               | been enabled by default.
        
           | mort96 wrote:
           | See my response to
           | https://news.ycombinator.com/item?id=32753207. I'm not saying
           | it will break everyone's FAT32 drives, but it _is_ a breaking
           | change in a filesystem, which seems like something kernel
           | people would usually try to avoid.
        
         | DannyBee wrote:
         | It's as backwards compatible as any other fat extension done so
         | far.
         | 
         | For example, LFN fails if you create too many files with the
         | same first 6 letters :)
         | 
         | I'm actually honestly not sure why representing all legal FAT32
         | file structures is a particularly useful goal?
         | 
         | FAT in particular, in all of it's forms, has always had
         | limitations and weirdness in filenames, etc.
        
           | mort96 wrote:
           | I don't understand your LFN example. Which FAT file structure
           | can be represented with LFN disabled that's no longer
           | possible to represent if you add support for LFN?
           | 
           | If BigFAT was actually backwards compatible, it would've been
           | a no-brainer to add support for in filesystem drivers. But
           | since it changes the interpretation of some legitimate
           | structures, adding support for BigFAT is a breaking change. I
           | don't know whether operating systems will want to make
           | breaking changes to their FAT32 filesystems, but it certainly
           | seems like a bigger ask.
        
             | lproven wrote:
             | My favourite sobriquet for MS has long been the DOS view of
             | an Office 97 installation in the filesystem:
             | 
             | MICROS~1
             | 
             | (Long name, Microsoft Office.)
             | 
             | So if you create files called MICROS~2 - MICROS~0 in theory
             | you can create enough abbreviated names that there are not
             | available short names for long filenames you wish to
             | create. Every LFN _must_ have a  "real" 8.3 counterpart.
        
         | chasil wrote:
         | There are so many good filesystems out there. Is it really
         | necessary to keep dragging FAT along?
         | 
         | ReactOS is using btrfs, which has so many useful options that
         | FAT will never see (zstd, xxhash, flash-aware options,
         | snapshots, send/receive, etc.). This is positioned both for
         | Linux and Windows.
         | 
         | Microsoft itself restrains ReFS to enterprise use, and btrfs
         | offers so much more functionality. We should stop using a file
         | system from the '80s.
        
           | selfhoster11 wrote:
           | BtrFS is unsafe for production use unless it's coupled with
           | really good backups.
           | 
           | On the other hand, NTFS on Windows, Ext* on Linux, or ZFS on
           | any supported OS, has not been known to eat data as
           | frequently.
        
             | chasil wrote:
             | With all due respect, this is now far from true.
             | 
             | "So, we'll repeat this once more: as a single-disk
             | filesystem, btrfs has been stable and for the most part
             | performant for years."
             | 
             | https://arstechnica.com/gadgets/2021/09/examining-btrfs-
             | linu...
        
             | Tijdreiziger wrote:
             | Synology uses Btrfs + mdadm RAID for their NAS boxes, which
             | are regarded as rock-solid.
             | 
             | https://www.synology.com/en-global/dsm/Btrfs
        
             | winter_blue wrote:
             | Is BtrFS _without RAID_ safe?
             | 
             | According to them
             | (https://btrfs.wiki.kernel.org/index.php/Status) only
             | RAID56 is unstable.
        
               | rleigh wrote:
               | There are still major bugs in the rest of it. You can
               | trivially corrupt a mirror. There are examples for how to
               | reproduce it exactly in qemu with virtual drives. I
               | caused me total dataloss on my first Btrfs filesystem at
               | least 8 years back. That bug is apparently still there.
               | The unbalancing issues are still there. I have zero trust
               | of Btrfs in any form.
        
           | mort96 wrote:
           | Camera manufacturers and SD card manufacturers can't start
           | shipping SD cards formatted with btrfs until Windows supports
           | it out of the box. They can start shipping SD cards formatted
           | with FAT32 and software/firmware which reads and writes
           | FAT32+BigFAT.
        
             | jchw wrote:
             | Now that exFAT is "open", I've seen it cropping up much
             | more often. SD cards often ship with it, especially large
             | ones.
        
               | LinAGKar wrote:
               | That happened before it was open. exFAT is the standard
               | filesystem on SDXC
        
             | umanwizard wrote:
             | If they can ship software that reads BigFAT, why can't they
             | ship software that reads btrfs?
        
               | guipsp wrote:
               | Because you only need the software for >4gb files and
               | block level access requires root or admin usually. This
               | is can be fully userspace if your OS already supports
               | Fat32 (it does).
        
               | creshal wrote:
               | 1. BTRFS is a lot more complex.
               | 
               | 2. Switching to BTRFS would be a breaking change. BigFAT
               | wouldn't be. You can still use the card in devices that
               | do not support it, without needing to reformat. Those
               | devices would just lose access to some files.
        
               | m-p-3 wrote:
               | Probably simplicity. It would be easier for a
               | manufacturer to do a quick firmware update that
               | implements BigFAT than having them support BTRFS.
        
               | mort96 wrote:
               | Other people have given good answers, but here's another
               | one: People's computers can already mount BigFAT-
               | formatted drives.
               | 
               | Do you know what happens when you insert a btrfs-
               | formatted SD card or USB stick into a Windows or macOS
               | machine? It tells you that the drive is unreadable and
               | asks if you want to initialize it. If the user answers
               | yes to that question, the system formats the drive and
               | all of their data is lost.
               | 
               | With a BigFAT-formatted drive, the system will mount it
               | no problem, the user will be able to browse the contents,
               | and the only weird part is that their largest files are
               | split into parts.
        
             | chasil wrote:
             | I guess what is needed is a BSD implementation of btrfs.
             | 
             | Still, something similar to fuse might help with the
             | licensing.
        
               | mort96 wrote:
               | No, what is needed is for Windows and macOS to support
               | btrfs out of the box.
        
             | axiolite wrote:
             | > can't start shipping SD cards formatted with btrfs until
             | Windows supports it out of the box
             | 
             | 3rd parties can write drivers for Windows, you know. A
             | small, read-only FAT partition on a USB stick or SD card
             | could contain the installable drivers necessary to
             | read/write the rest of the disk.
             | 
             | However, that's unnecessary. The best option for a
             | universal file system is UDF. Windows, Mac, and Linux all
             | have full read/write support.
             | 
             | See: https://github.com/JElchison/format-udf
        
             | georgyo wrote:
             | More specifically, they need a filesystem that both Windows
             | and MacOS can read. No one wants to take their SD card to a
             | friend's computer and have it not work for reasons they
             | won't understand.
             | 
             | The shared set there is basically just fat and exfat.
             | 
             | If Microsoft and Apple collaborated on a new filesystem, or
             | even just supported it, then we might have a possible
             | successor. However even with that, the millions of already
             | shipped devices won't support it. This during the
             | transition period of many years there will still need to be
             | support for fat.
             | 
             | That keeps fat the lowest common denominator and everything
             | supporting it.
        
               | BearOso wrote:
               | Remember last time they tried a universal media
               | filesystem with UDF? It was implemented in the most
               | incompatible ways as a token gesture by both Microsoft
               | and Apple. These companies want their own, patented,
               | proprietary fs so they can maintain lock-in.
               | 
               | The only way to get a universal standard is to have the
               | community do it and have enough people use it that the
               | big companies have to capitulate.
        
               | ComodoHacker wrote:
               | The problem is you can't get there without out-of-the-box
               | support.
        
           | mschuster91 wrote:
           | > Is it really necessary to keep dragging FAT along?
           | 
           | Anything involving embedded and without deep pockets has no
           | other option, FAT (sadly) still is the least common
           | denominator. Some speak ExFAT, but not sure how good the
           | tooling support is outside of Microsoft, and there are still
           | patent concerns.
        
             | creshal wrote:
             | Even without patent concerns, exFAT takes more effort to
             | implement (lots of features you might not need) and ends up
             | requiring more ROM space that may or may not be
             | available... even if you want to write files exceeding 4GB
             | to some external media.
             | 
             | e.g. some widget without network connection that optionally
             | logs an audit trail to an attached USB media, could still
             | end up with only a couple hundred kilobytes of soldered-on
             | ROM to store the whole firmware, while wanting to write
             | more than 4GB of audit logs.
        
             | loeg wrote:
             | I believe the exFAT patents expire or expired this year.
        
           | kreco wrote:
           | Nothing beats the simplicity of FAT.
           | 
           | Btrfs has a lot of bugs while being active for a long time.
           | This is mostly related to its complexity.
           | 
           | If I'm going to implement a filesystem for a custom hardware
           | I would definitely not chose btrfs.
        
             | jonny_eh wrote:
             | > Nothing beats the simplicity of FAT.
             | 
             | Or the sheer ubiquity, and therefore cross-device
             | compatibility.
        
             | chasil wrote:
             | If you want snapshots, dedup, transparent compression, and
             | scrubs then you have precisely three open and/or available
             | choices: ZFS, btrfs, and ReFS.
             | 
             | By all means, choose the Microsoft solution, because patent
             | licensing is good for everyone.
             | 
             | And the bug myth past into history years ago.
             | 
             | "So, we'll repeat this once more: as a single-disk
             | filesystem, btrfs has been stable and for the most part
             | performant for years."
             | 
             | https://arstechnica.com/gadgets/2021/09/examining-btrfs-
             | linu...
        
               | guipsp wrote:
               | But I just want 5GB files
        
               | chasil wrote:
               | Microsoft just wants a check from you.
               | 
               |  _We are all forced to pay for this ancient software
               | every time we buy a device that uses it._
               | 
               | Wouldn't this money be better used elsewhere?
               | 
               | https://en.m.wikipedia.org/wiki/File_Allocation_Table#Pat
               | ent...
        
               | Dylan16807 wrote:
               | You know patents have a limited life, right?
               | 
               | x86_64 with SSE2 is also patent-free right now, as an
               | example.
        
               | guipsp wrote:
               | Microsoft isn't getting a check from me using FAT32.
        
               | teknopaul wrote:
               | Hmm that's like saying Google is free.
        
               | ksec wrote:
               | AFAIK, FAT32 is Patent Free, even the Long File Name
               | Patent has expired. The only patent left are on exFAT.
        
       | scohesc wrote:
       | Would it not be possible to create a filesystem with modern
       | capabilities but with backwards compatibility with FAT? Why can't
       | we just have "legacy" commands built into the ReFS filesystem
       | that process any FAT filesystem access?
       | 
       | I'm very ignorant to this but I'd love some insight from someone
       | vastly more knowledgeable than me.
        
       | quickthrower2 wrote:
       | Is the big file handling seemless? If not why not just split
       | files and use regular FAT32.
       | 
       | And what about converting FAT32 to a linux partition? Or buy a
       | new disk and move data over to that.
       | 
       | Edit: it is a genuine question. downvote implies not but honestly
       | it is.
        
       | JAA1337 wrote:
       | Awesome concept, especially for academia ... but is there a value
       | proposition?
       | 
       | I love seeing this, don't get me wrong. I am just curious is
       | there are any real world applications for this?
        
         | Bakary wrote:
         | I already use FAT32 for some USB sticks when I need to be able
         | to use them on various OSes without having to give it any
         | thought, or for long term archiving.
         | 
         | This would be extremely niche but would have its audience.
         | Heck, I wouldn't be surprised if HN readers adopted it just to
         | taste the thrill of unlimited and obscene power.
        
         | noAnswer wrote:
         | > but is there a value proposition?
         | 
         | Straight from their FAQ: We see emFile customers asking for
         | solutions for bigger files. Implementing exFAT is not an option
         | for us, as it is patent encumbered. SEGGER would need
         | Microsoft's permission to implement and offer it, and our
         | customers need to deal with Microsoft again to be able to use
         | it in their products. This can be time-consuming and also
         | expensive. We feel there should be a free alternative. The more
         | popular BigFAT becomes, the better.
         | 
         | I guess using anything but FAT would make it hard for their
         | developer base.
        
         | mort96 wrote:
         | It would be great to have a non-patent-encumbered simple file
         | format that's supported everywhere. The fact that this is based
         | on FAT32 might help adoption, everyone's computers can already
         | at least read a BigFAT drive, and BigFAT support could be added
         | at the application level for systems which don't support it at
         | an OS level.
        
           | prmoustache wrote:
           | Are the filesystem used on bsd and linux distros patent
           | encumbered? Isn't UFS2 simple enough?
        
             | mort96 wrote:
             | UFS2 might be the technically perfect tool for the job, but
             | that doesn't matter when Windows doesn't support it. A
             | camera manufacturer or SD card manufacturer can't start
             | shipping their customers SD cards formatted with UCS2 when
             | it's not supported by Windows. They could start shipping
             | FAT32 SD cards and software and firmware which can read and
             | write FAT32+BigFAT.
        
             | yyyk wrote:
             | If you wish for an fs common to both BSD and Linux, ext2fs
             | would be perfect - better than UFS for the job.
        
       | bArray wrote:
       | Is this only compatible with FAT32, or is it also compatible with
       | FAT12/16? It would be very cool if this would support floppy
       | disks.
       | 
       | Regarding the format, once you convert it, does the target device
       | need to have a driver to support the format? It mentions that
       | this would allow for > 4GB files for TVs, but these are typically
       | non-updated very out of date OSes.
       | 
       | I think MS missed a trick by not making the boot sector also
       | contain a simplistic driver, although it would have been a push
       | to keep it all down at 512 bytes.
        
         | Dylan16807 wrote:
         | > Is this only compatible with FAT32, or is it also compatible
         | with FAT12/16? It would be very cool if this would support
         | floppy disks.
         | 
         | It's simple enough to work on basically anything, but for what
         | purpose?
         | 
         | The max file size on FAT12/16 is the same as the max drive
         | size.
         | 
         | And FAT32 is very easy to implement for any system dealing with
         | multiple megabytes.
        
         | pantalaimon wrote:
         | How do you get files > 4 GiB on a floppy disk?
        
       | steeleduncan wrote:
       | Is there a linux kernel driver for this somewhere?
        
       | phkahler wrote:
       | The question I have is, why Segger? When I saw this I was like
       | "the debugger company?!?!" Clearly this wouldn't fall under their
       | business, so it makes sense for them to open it up, but why did
       | they do it in the first place?
        
         | matja wrote:
         | They have an entire RTOS ecosystem which supports a gazillon
         | different microcontrollers.
        
         | weinzierl wrote:
         | They offer their own file system implementation (emFile) which
         | supports either their own storage format (EFS) or FAT. The
         | BigFAT article is posted in the emFile section of their
         | website.
         | 
         | My suspicion is that customers are bugging them to support
         | large files in emFile and they don't want to pay the license
         | fee for exFAT. I think they even can't do that with their
         | current licensing model, which is one-time per product (not
         | item) or product-family payment.
         | 
         | EDIT: I tried to find out if Microsoft's exFAT is licensed per
         | product or per unit and I found that it used to be a 300000 USD
         | flat fee in 2009 but seems to be free since 2019. So my theory
         | from above has no basis and I wonder why Segger does not simply
         | implement exFAT?
        
           | noAnswer wrote:
           | It is not true that is "free since 2019".
           | 
           | Source:
           | 
           | https://www.microsoft.com/en-
           | us/legal/intellectualproperty/t...
           | 
           | https://www.paragon-software.com/exfat-license/
           | 
           | https://en.wikipedia.org/wiki/ExFAT#Legal_status
           | 
           | You maybe of the hook if you use Linux >= 5.7. And it seem
           | that you are of the hook if you are a member of the Open
           | Invention Network (OIN).
           | 
           | But SEGGER's embOS is not based on Linux and their costumers
           | a OEMs themselves. So their costumers would need to be OIN
           | members or pay royalties to MS.
        
             | weinzierl wrote:
             | This is interesting, thanks. So the Linux kernel contains
             | essentially non-free code that is, despite being under GPL,
             | in effect not usable by others because of patents.
        
       | stuaxo wrote:
       | If they want it to spread they should also write a fuse
       | implementation and think about operating system support for Linux
       | or BSD.
        
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