Amstrad's implementation of CP/M+
Amstrad distributed CP/M+ on the side 4 of the system discs that came with the CPC6128. On side 1 was CP/M 2.2.
- Amstrad CP/M+ uses Amstrad's "System" format. This is 40 tracks, 1 side, 9 sectors per track numbered &41-&49. There are two reserved tracks, then the directory which has 64 entries, and then the data area.
- CP/M is booted using an RSX command "|CPM" which is implemented in the Amstrad disc rom (AMSDOS).
- |CPM loads track 0, side 0, sector &41 into RAM at &100-&2ff. This is the boot sector and contains the boot program.
- The boot program then loads the directory from track 2, sector &41.
- The boot program locates a program with extension "EMS".
- This program is loaded into RAM at &c00.
- This is then executed. (EMS contains the BIOS, BDOS and relocates and re-configures the memory. CP/M doesn't use the CP/M 2.2 BIOS from the Amstrad disc ROM.)