| D: Example CP/M and DOS disc structures |
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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 verified 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 |
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 |
Altos 586
| |
Capacity |
720K |
| |
Sectors per track |
9 |
| |
Bytes per sector |
512 |
| |
Directory entries |
176 |
| |
Sectors per cluster |
8 = 4096 bytes |
| |
Reserved tracks |
2 |
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 |
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 |
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 |
IBM PC-DOS 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 PC-DOS 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 |
IBM PC-DOS 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 PC-DOS 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 |
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 |
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 |
Proteus
| |
Capacity |
800K |
| |
Sectors per track |
10 |
| |
Bytes per sector |
512 |
| |
Directory entries |
128 |
| |
Sectors per cluster |
8 = 4096 bytes |
| |
Reserved tracks |
2 |
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 |