D: Example CP/M and DOS disc
structures
Below are examples of sorne of the disc formats that may be
encountered. Although this information is intended to be reliable
the format and layout of any alien disc should be very carefully
before details of its structure are used.
Refer to Chapter Nine for further information on the internals
of disc structures. Remember that the number and position of FAT
sectors and the root directory may vary from disc to disc. For
DOS formats the relevant information should be contained at the
beginning of sector zero.
DOS terminology is used here, though it should be noted that
many of these formats are CP/M rather than DOS.
Acorn DOS boot disc (DISK 1)
| Capacity |
640k |
| Sectors per track |
16 |
| Bytes per sector |
256 |
| Directory entries |
112 |
| Sectors per cluster |
8 = 2048 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
Acorn 512 DOS Plus
| Capacity |
800k |
| Sectors per track |
5 |
| Bytes per sector |
1024 |
| Directory entries |
192 |
| Sectors per cluster |
1 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
Acorn Z80
| Capacity |
400k |
| Sectors per track |
10 |
| Bytes per sector |
256 |
| Directory entries |
128 |
| Sectors per cluster |
8 = 2048 bytes |
| Reserved tracks |
1 |
| Number of FATs |
|
Archimedes MS DOS 800K
| Capacity |
800k |
| Sectors per track |
5 |
| Bytes per sector |
1024 |
| Directory entries |
192 |
| Sectors per cluster |
1 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
Almarc Spirit 16
| Capacity |
790K |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
128 |
| Sectors per cluster |
4 = 2048 bytes |
| Reserved tracks |
2 |
| Number of FATs |
|
Altos 586
| Capacity |
720K |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
176 |
| Sectors per cluster |
8 = 4096 bytes |
| Reserved tracks |
2 |
| Number of FATs |
Gemini CP/M
| Capacity |
790K |
| Sectors per track |
10 |
| Bytes per sector |
512 |
| Directory entries |
128 |
| Sectors per cluster |
8 = 4096 bytes |
| Reserved tracks |
2 |
| Number of FATs |
|
IBM PC CP/M-86 single sided
| Capacity |
160 Kb |
| Sectors per track |
8 |
| Bytes per sector |
512 |
| Directory entries |
64 |
| Sectors per cluster |
2 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
|
IBM PC CP/M86 double sided
| Capacity |
320 Kb |
| Sectors per track |
8 |
| Bytes per sector |
512 |
| Directory entries |
128 |
| Sectors per cluster |
4 = 2048 bytes |
| Reserved tracks |
1 |
| Number of FATs |
|
IBM PCDOS 160Kb
| Capacity |
160 Kb |
| Sectors per track |
8 |
| Bytes per sector |
512 |
| Directory entries |
64 |
| Sectors per cluster |
1 = 512 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
IBM PCDOS 180 Kb
| Capacity |
180 Kb |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
64 |
| Sectors per cluster |
1 = 512 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
IBMPCDOS 320 Kb
| Capacity |
320 k |
| Sectors per track |
8 |
| Bytes per sector |
512 |
| Directory entries |
112 |
| Sectors per cluster |
2 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
IBM PCDOS 360Kb
| Capacity |
360 k |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
112 |
| Sectors per cluster |
2 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
ICL PC CP/M
| Capacity |
720K |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
128 |
| Sectors per cluster |
4 = 2048 bytes |
| Reserved tracks |
4 |
| Number of FATs |
|
Motorola VME/10 CP/M-86
| Capacity |
320K |
| Sectors per track |
8 |
| Bytes per sector |
256 |
| Directory entries |
128 |
| Sectors per cluster |
8 = 2048 bytes |
| Reserved tracks |
2 |
| Number of FATs |
|
Nokia PC MS DOS format
| Capacity |
720K |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
144 |
| Sectors per cluster |
2 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
OTRONA Attache
| Capacity |
400K |
| Sectors per track |
10 |
| Bytes per sector |
512 |
| Directory entries |
128 |
| Sectors per cluster |
8 = 2048 bytes |
| Reserved tracks |
1 |
| Number of FATs |
|
Proteus
| Capacity |
800K |
| Sectors per track |
10 |
| Bytes per sector |
512 |
| Directory entries |
128 |
| Sectors per cluster |
8 = 4096 bytes |
| Reserved tracks |
2 |
| Number of FATs |
|
Philips PG9000 GEMDOS
| Capacity |
640K |
| Sectors per track |
16 |
| Bytes per sector |
256 |
| Directory entries |
128 |
| Sectors per cluster |
4 = 1024 bytes |
| Reserved tracks |
2 |
| Number of FATs |
2 |
RML Nimbus MS DOS format
| Capacity |
720 k |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
112 |
| Sectors per cluster |
2 = 1024 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |
Tandy model 2000 MS DOS
| Capacity |
720K |
| Sectors per track |
9 |
| Bytes per sector |
512 |
| Directory entries |
112 |
| Sectors per cluster |
4 = 2048 bytes |
| Reserved tracks |
0 |
| Number of FATs |
2 |