System information

You should use IBM-compatible disks rather than disks that have previously been used with any
ISIS version. In particular, the ISIS FORMAT operation produces nonstandard sector numbering
throughout the disk. This nonstandard numbering seriously degrades the performance of CP/M,
and causes CP/M to operate noticeably slower than the distribution version. If it becomes
necessary to reformat a disk, which should not be the case for standard disks, a program can be
written under CP/M that causes the MDS 800 controller to reformat with sequential sector
numbering (1-26) on each track.
Generally, IBM-compatible 8-inch disks do not need to be formatted. However, 5 1/4-inch disks
need to be formatted.
End of Section 1
1.8 Operation of CP/M on the MDS CP/M Operating System Manual