README.dosfstools-2.x 2.8 KB

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  1. Atari format support
  2. ====================
  3. Both mkdosfs and dosfsck now can also handle the Atari variation of
  4. the MS-DOS filesystem format. The Atari format has some minor
  5. differences, some caused by the different machine architecture (m68k),
  6. some being "historic" (Atari didn't change some things that M$
  7. changed).
  8. Both tools automatically select Atari format if they run on an Atari.
  9. Additionally the -A switch toggles between Atari and MS-DOS format.
  10. I.e., on an Atari it selects plain DOS format, on any other machine it
  11. switches to Atari format.
  12. The differences are in detail:
  13. - Atari TOS doesn't like cluster sizes != 2, so the usual solution
  14. for bigger partitions was to increase the logical sector size. So
  15. mkdosfs can handle sector sizes != 512 now, you can also manually
  16. select it with the -S option. On filesystems larger than approx. 32
  17. MB, the sector size is automatically increased (stead of the
  18. cluster size) to make the filesystem fit. mkdosfs will always use 2
  19. sectors per cluster (also with the floppy standard configurations),
  20. except when directed otherwise on the command line.
  21. - From the docs, all values between 0xfff8 and 0xffff in the FAT mark
  22. an end-of-file. However, DOS usually uses 0xfff8 and Atari 0xffff.
  23. This seems to be only an consmetic difference. At least TOS doesn't
  24. complain about 0xffff EOF marks. Don't know what DOS thinks of
  25. 0xfff8 :-) Anyway, both tools use the EOF mark common to the
  26. system (DOS/Atari).
  27. - Something similar of the bad cluster marks: On Atari the FAT values
  28. 0xfff0 to 0xfff7 are used for this, under DOS only 0xfff7 (the
  29. others can be normal cluster numbers, allowing 7 more clusters :-)
  30. However, both systems usually mark with 0xfff7. Just dosfsck has to
  31. interpret 0xfff0...0xfff7 differently.
  32. - Some fields in the boot sector are interpreted differently. For
  33. example, Atari has a disk serial number (used to aid disk change
  34. detection) where DOS stores the system name; the 'hidden' field is
  35. 32 bit for DOS, but 16 bit for Atari, and there's no 'total_sect'
  36. field; the 12/16 bit FAT decision is different: it's not based on
  37. the number of clusters, but always FAT12 on floppies and FAT16 on
  38. hard disks. mkdosfs nows about these differences and constructs the
  39. boot sector accordingly.
  40. - In dosfsck, the boot sector differences also have to known, to not
  41. warn about things that are no error on Atari. In addition, most
  42. Atari formatting tools fill the 'tracks' and 'heads' fields with 0
  43. for hard disks, because they're meaningless on SCSI disks (Atari
  44. has/had no IDE). Due to this, the check that they should be
  45. non-zero is switched off.
  46. - Under Atari TOS, some other characters are illegal in filenames:
  47. '<', '>', '|', '"', and ':' are allowed, but all non-ASCII chars
  48. (codes >= 128) are forbidden.
  49. - Roman <Roman.Hodek@informatik.uni-erlangen.de>