=== Technical information ===
CP/M 2.2 uses the firmware, . There are 2 BIOS jumpblocks in RAM and the platform specific part of "ENTER FIRMWARE" which can be patched. The normal CPM BIOS jumpblock and an extended one. CP/M uses the firmware extensively and enters it via "ENTER FIRMWARE". The BIOS is in the AMSDOS ROM, and this calls through to uses the firmware through jumpblocks in RAM. The AMSDOS ROM also uses part of the RAM for XDPB storage and a special "ENTER FIRMWARE" functionsector buffer. By having the BIOS in ROM, using the firmware and having the screen at &c000-&ffff, this gives 41K as the 33KB TPA for a CPC 64KB systemwhich is OK.
* Amstrad CPM2.2 uses Amstrad's "System" format. This is 40 tracks, 1 side, 9 sectors per track numbered &41-&49. Each sector holds 512Bytes. There are two reserved tracks, then the directory which has 64 entries, and then the data area.
* WBOOT loads multiple sectors from the reserved tracks, this is the platform independent CPM system (BDOS etc).
=== Memory Map ===