DOS ain't dead - BD-R with UDF filesystem

BD-R with UDF filesystem (Miscellaneous)

posted by Zyzzle, 20.12.2020, 10:06

> But, I think it should be possible to format all optical media as FAT32
> even though it is not normally done. I haven't actually yet experimented
> with anything other than DVD-RAM media, but one of the things I intend to
> do is see if I can format other types of optical media as FAT32 and have
> DOS (at least MS-DOS) be able to read it. Right now, I don't see a reason
> why it wouldn't work but I will need to try it and see if any unforeseen
> issues arise. Also, one reason I would like try to do it with other
> optical media besides DVD-RAM is that DVD-RAM media is VERY difficult to
> find these days, even though it's actually superior to the other optical
> media in some ways.

But, formatting optical media (especially BD-R) as FAT32 won't get you much, as of course FAT32 will not allow files > 4GB and MS-DOS won't allow long unsigned integer files between 2 and 4 GB to be read, since only signed integer file sizes seem to be supported. It's a VERY frustrating limitation, since filesizes can't be negative, why waste the upper bit? That limitation would need to be removed first. BD-Rs are UDF exclusively, I believe, and UDF allows creation of files up to 2TB (?) I believe, certainly well beyond 4GB, at least, since discs often contain single .m2ts files that are beyond 45 GB in length.

What are some of the hurdles in coding a UDF-capable file-system driver for DOS? Does MSCDEX allow only ISO9660 format, or does it also support FAT32? I also have wondered why UDF support was never envisioned for DOS, as such a driver, like the two or three existing NTFS filesystem drivers for MS-DOS would be very, very useful. Is the old High-Sierra format compatible with 2k sectors and / or file sizes larger than 4GB? So many questions, and few answers.

Along these lines, supporting 4Kb sector-size hard disks should be possible in MS-DOS, if 2048-byte sector sizes are possible and will work. Is it possible with a simple patch to IO.SYS and COMMAND.COM?

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Complete thread:

BD-R with UDF filesystem - david, 17.12.2020, 10:26 (Miscellaneous)
- BD-R with UDF filesystem - RayeR, 18.12.2020, 15:14
  - BD-R with UDF filesystem - bretjohn, 19.12.2020, 21:57
    - BD-R with UDF filesystem - Zyzzle, 20.12.2020, 10:06
      - BD-R with UDF filesystem - bretjohn, 21.12.2020, 21:33
        BD-R with UDF filesystem - RayeR, 21.12.2020, 23:01
        BD-R with UDF filesystem - RayeR, 25.12.2020, 09:19
        BD-R with UDF filesystem - RayeR, 26.12.2020, 22:53
        BD-R with UDF filesystem - Zyzzle, 27.12.2020, 04:02
        BD-R with UDF filesystem - RayeR, 27.12.2020, 21:10
        BD-R with UDF filesystem - Zyzzle, 22.12.2020, 04:44
        BD-R with UDF filesystem - RayeR, 22.12.2020, 05:46
        BD-R with UDF filesystem - Zyzzle, 22.12.2020, 06:14
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - ecm, 22.12.2020, 12:50
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - bretjohn, 22.12.2020, 19:03
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - tom, 22.12.2020, 22:05
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - RayeR, 22.12.2020, 23:43
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - bretjohn, 23.12.2020, 19:51
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - RayeR, 23.12.2020, 21:15
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - Zyzzle, 24.12.2020, 04:18
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - rr, 24.12.2020, 13:41
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - mceric, 23.12.2020, 02:31
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - RayeR, 23.12.2020, 19:37
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - bretjohn, 23.12.2020, 22:24
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - bretjohn, 27.12.2020, 16:40
        BD-R with UDF filesystem - FS redirector with 64-bit sizes - ecm, 25.12.2020, 21:24