[HN Gopher] Petit Fat File System Module
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Petit Fat File System Module
Author : elvis70
Score : 85 points
Date : 2020-10-13 15:27 UTC (7 hours ago)
(HTM) web link (elm-chan.org)
(TXT) w3m dump (elm-chan.org)
| halayli wrote:
| Been checking elm-chan since 1999/2000 when I implemented his mp3
| player using atmel.
|
| I admire his consistency.
| andyjpb wrote:
| I've been using this recently and, because it doesn't ever modify
| the file system structures, you don't have to worry about
| unmounting the volume cleanly.
|
| It can write to files, but it can't create or resize them. For
| that (and more), you want FatFs, the full featured version:
| http://elm-chan.org/fsw/ff/00index_e.html
|
| elm-chan has also written an AVR bootloader that can update the
| flash from, for example, an SDCard. It uses this Petit FAT File
| System Module and requires a 4K bootloader section (so mostly of
| use on the ATMega1284).
| howerj wrote:
| I have noticed there are quite a few FAT-32 implementations out
| there, but none that do what I want. Ideally what I want is
| something that would do the following; allow the creation of a
| new FAT-32 image file of a specified length given a target
| directory.
|
| The program (or programs/scripts) must be command line driven and
| run under both Windows and Linux (so they can be integrated into
| our build system).
|
| The use case is the following; the creation of a single binary
| image containing some firmware and a (per-unit) custom FAT-32
| partition, both of which would effectively concatenated together.
|
| Does anyone have any ideas? Otherwise I might have to make
| something myself.
| a1369209993 wrote:
| > allow the creation of a new FAT-32 image file _of a specified
| length_ given a target directory [emphasis added]
|
| I think that's your problem: file systems are supposed to go
| onto a preexisting block device, which you'll need to create
| seperately. For example, on my system: dd
| if=/dev/zero of=/tmp/foo.dos bs=512 count=128K mkdosfs -F
| 32 /tmp/foo.dos
|
| Once you've created the filesystem, fill it with:
| mkdir /tmp/foo/ sudo mount -t msdos -o loop /tmp/foo.dos
| /tmp/foo/ # dump stuff into /tmp/foo/ sudo umount
| /tmp/foo.dos # or /tmp/foo/ # filesystem is in
| /tmp/foo.dos
| ptspts wrote:
| mtools, containing the mformat and mcopy tools.
| any1 wrote:
| There's also genimage [1] which uses mtools for FAT, but it
| can also do ext2 and more.
|
| [1] https://github.com/pengutronix/genimage
| howerj wrote:
| That looks like it might work, thank you. My search did not
| find this.
| jaclaz wrote:
| +1
|
| The mtools/mformat are not AFAIK released pre-built for
| Windows, in case of need here is a build:
|
| http://reboot.pro/topic/14354-buidlingmodifying-floppy-
| image...
|
| Syntax/option for mformat are a bit complex, again in case of
| need here is a small batch that hopefuly makes commands
| clearer:
|
| http://reboot.pro/topic/21664-makeiso/page-4#entry205455
| koolba wrote:
| I can't speak for Windows, but on any *nix OS you can do this
| with a loop back device. You'd have to determining in advance
| and likely round up a bit. But it's a literally a couple line
| shell script.
| shawnz wrote:
| On Windows you could create and mount a VHD file and format
| it as FAT32 by using the diskpart utility, with the commands
| "create vdisk", "attach vdisk", and "format"
| howerj wrote:
| Yeah, it is easy to do, but only on Unixen, the dev
| environment I am working on is primarily run under Windows
| (and also maybe Linux in the future).
| m463 wrote:
| WSL / WSL2 might be one answer
| kevin_thibedeau wrote:
| You can adapt FatFS to do this. You just have to implement a
| few low level I/O routines to work using an conventional file
| as a fake block device.
| morio wrote:
| Why does the author not just put it on github/gitlab/... instead
| of only offering a .zip? It's 2020 last time I checked.
| panic wrote:
| If it's that onerous to download the zip, maybe we should build
| a tool to browse .zip/.tgz source links instead of pressuring
| everyone to centralize all source code on the planet into just
| two web sites.
| tom_ wrote:
| Wait, what's the other one that isn't GitHub? Sounds like we
| need to start working on the people still putting their stuff
| there!
| SahAssar wrote:
| Not everyone wants to work that way, and having a public git as
| a requirement is ridiculous. The software is FOSS, why are you
| complaining?
| morio wrote:
| Never said it should be a requirement. But downloading a .zip
| file from a site which does not have a valid SSL certificate
| nor supports SSL in the first place does not instill
| confidence. Software security is a thing.
| SahAssar wrote:
| Agreed about the SSL/TLS, but the comment sounded more like
| not having a public git was the complaint.
| cbluth wrote:
| this link doesnt work
| theamk wrote:
| Works for me?
|
| > Petit FatFs is a sub-set of FatFs module for tiny 8-bit
| microcontrollers. It is written in compliance with ANSI C and
| completely separated from the disk I/O layer. It can be
| incorporated into the tiny microcontrollers with limited memory
| even if the RAM size is less than sector size.
| vosper wrote:
| Works fine for me - maybe it has intermittent errors?
| morio wrote:
| The site does not have a valid SSL certificate. Some browsers
| will block it.
| hinkley wrote:
| If it wasn't hugged to death before, it definitely is now. 403
| errors for this path and for /
| grawprog wrote:
| Works fine for me.
|
| >Petit FatFs is a sub-set of FatFs module for tiny 8-bit
| microcontrollers. It is written in compliance with ANSI C and
| completely separated from the disk I/O layer. It can be
| incorporated into the tiny microcontrollers with limited memory
| even if the RAM size is less than sector size. Also full
| featured FAT file system module is available here.
|
| http://elm-chan.org/fsw/ff/00index_e.html
|
| >Features Very small RAM consumption (44 bytes work area +
| certain stack). Very small code size (2K-4K bytes). FAT12,
| FAT16 and FAT32. Single volume and Single file. Streaming file
| read. File write function with some restrictions.
| arcadian33 wrote:
| PetitFatFS was handy in a recent build. I was creating a box that
| could be placed on marine equipment to collect vibrations data,
| but to capture the modes of interest it had to read accelerometer
| data and write it to a microSD card at >=660[Hz]. I don't have a
| programming background and thus had trouble creating code which
| fit onto the tiny memory of the microcontroller being used.
| PetitFatFS worked beautifully, and saved a ton of headache on my
| end. It added the step of creating the storage files on the
| microSD card prior to inserting it, but that was acceptable for
| this project.
| sgtnoodle wrote:
| I recently did a search for embedded fat implementations, and
| this one stood out well above the rest.
| nom wrote:
| Ah ELM. I always try to urge everyone interested in low-level
| embedded systems engineering to browse elm-chan.org, it's such a
| treasure trove.
|
| He describes himself as "Mediocre embedded system engineer" but
| he is way too humble, the skill he shows is so incredible that I
| often find myself speechless whenever I look at his projects.
|
| Go there, look around and recommend it to everyone. You will not
| regret it.
| rkagerer wrote:
| Agreed. Anyone know how to get in touch with him? I used his
| audio player code, found some bugs, and want to give him the
| fixes. Tried the email listed on his Profile page, but never
| heard back.
|
| ChaN, if you're out there:
|
| https://i.imgur.com/E8Z29VE.png
|
| The original code fails to load WAV's containing metadata -
| even though an intent to tolerate them appears written into
| some of the handlers (DISP, LIST FCC, etc). I can provide files
| from Audacity which reproduce the issue.
|
| Moved remaining details here to avoid boring the HN audience:
| https://pastebin.com/raw/XdneQ8xh
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(page generated 2020-10-13 23:00 UTC)