Atari 400 Technical Reference Manual page 6

Cartridges A and B
Mapped 1/0
Resident OS and Floating Point Package ROM
Central Data Base Description
Memory Dynamics
System Initialization Proce'ss
Changing Screen Modes
5 1/0 SUBSYSTEM
Central 1/0 Utility
CIO Design Philosophy
DEVICE INDEPENDENCE
DATA ACCESS METHODS
MULTIPLE DEVICEIFILE CONCURRENCY
UNIFIED ERROR HANDLING
DEVICE EXPANSION
CIO CALLING MECHANISM
HANDLER ID -- ICHID [0340]
DEVICE NUMBER -- ICDNO [0341]
COMMAND BYTE -- ICCMD [0342J
STATUS -- ICSTA [0343J
BUFFER ADDRESS
ICBAL[0344J AND ICBAH [0345]
PUT ADDRESS --
ICPTL [0346] AND ICPTH [0347]
BUFFER LENGTHIBYTE COUNT --
ICBLL [0348] and ICBLH [0349]
AUXILIARY INFORMATION --
ICAX1 [034AJ and ICAX2 [034B]
REMAINING BYTES (ICAX3-ICAX6)
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