This requires a HD20 capable X-DDOS because it checks for a specific variable set by X-DDOS if it detects the hard-disk. The main hard disc functions are in bank 0, with common hard disk buffer read/write in the common C7 bank at &FE00. The hard disc is accessible in CPM+ with drive D,E,F and G.
DPB description:
SPT: &00cc (204) (128 byte records)
BSH: 5
BLM: &1f
EXM: &1
DSM: &50D
DRM: &1ff (512 entries in directory)
AL0/AL1: &00f0 (4 blocks for directory)
CKS: &8000 (fixed disc)
OFFS: &0001
PSH: &02
PHM: &03
* supports both 50hz and 60hz displays.
If 60hz is detected the Vertical Sync is set to 16 lines and the hsync is set to 4. Otherwise it remains unchanged.