Disc format

Revision as of 12:52, 21 February 2019 by JohnElliott (Talk | contribs)

CPCs could read discs formatted in three separate ways. Several high-capacity disc operating systems existed to add new formats to the three standard ones.

Standard CPC disc formats

  • Data: 180k single-sided. 40 tracks of nine 512-byte sectors each. Sectors numbered &C1 to &C9. 64 directory entries. Can also be read by PCWs. The useable capacity is 178k.
  • System: 180k single-sided. 40 tracks of nine 512-byte sectors each. Sectors numbered &41 to &49. 64 directory entries. Two reserved tracks containing CP/M BIOS. The useable capacity is 169k.
  • IBM: 160k single-sided. 40 tracks of eight 512-byte sectors each. Sectors numbered &01 to &08. Provided for compatibility with CP/M-86 (and DR-DOS 1.0). Used by very few CPC purchasers, but Locomotive Software stated that this was invaluable for cross-assembly. The useable capacity is 158k.
  • Vendor: Term used for System format discs with no software in the reserved tracks. The useable capacity is 169k.

All these disc formats use a CP/M based filesystem.

Third-party CPC disc formats

  • FAT formats [1] (invented by MS-DOS; supported by SymbOS, DOS Copy, ReadDSK, DSK-CPC)
  • MS800 formats
  • Prem format (supported by Stream2)
  • RODOS formats
  • ROMDOS formats (also supported by ParaDOS: D80 supported by S-DOS and 400K/S)
  • Ultraform
  • Vortex (80 tracks, 2 sides, 9 sectors of 512 bytes, 2 reserved tracks, 704 KB; supported by FutureOS and XD-DOS)
  • Xexor formats (also supported by ParaDOS)
  • XD-DOS (supports 0.7 MB Data-, System- and Vortex- formats)
  • etc.??

References