Table of Contents
Advertisement
Appendix
J
Physical Format
Of Hard
Disks
CP/M-86 restricts the maximum size of a disk to 8MB. The APC hard disk units
have a 10MB capacity. Therefore, to maintain compatibility with CP/M-86, the
APC CBIOS views each physical hard disk unit as two logical disk drives. This
structure provides additional benefits.
• The drives may be initialized independently.
• Free space is allocated independently for the two drives.
• The system can physically copy from one drive to the other.
The system supports up to two physical hard disk units, labelled 0 and 1. The drives
are labelled E and F (unit 0), G and H (unit 1).
PHYSICAL FORMAT
Each drive is organized in the following format, as shown in Figure J-1.
• 89.5 cylinders
• 562 allocation blocks
• 4.60MB disk space
• 24 tracks free space (for track reallocation)
The disk space is organized as follows:
• 256 bytes/sector
• 26 sectors/track (0-25)
• 8 tracks/cylinder (0-7)
• 181 cylinders/unit (0-180)
J-l
Advertisement
Table of Contents
