From CPCWiki - THE Amstrad CPC encyclopedia!
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  (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)
- 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)