The BIOS begins with the following jumps to service routines:
JMP BOOT ;-3: Cold start routine
JMP WBOOT ; 0: Warm boot - reload command processor
JMP CONST ; 3: Console status
JMP CONIN ; 6: Console input
JMP CONOUT ; 9: Console output
JMP LIST ;12: Printer output
JMP PUNCH ;15: Paper tape punch output
JMP READER ;18: Paper tape reader input
JMP HOME ;21: Move disc head to track 0
JMP SELDSK ;24: Select disc drive
JMP SETTRK ;27: Set track number
JMP SETSEC ;30: Set sector number
JMP SETDMA ;33: Set DMA address
JMP READ ;36: Read a sector
JMP WRITE ;39: Write a sector
In CP/M 2 and later, the following extra jumps appear:
JMP LISTST ;42: Status of list device
JMP SECTRAN ;45: Sector translation for skewing