H.2 XHDI terminology

Definition of data types:

UWORD:  16-bit, unsigned
LONG:   32-bit, signed
ULONG:  32-bit, unsigned
char *: 32-bit, pointer to a zero terminated string

major:

Major Device Number

0..7:	Devices on the ACSI bus with ATARI-compatible command set
8..15:	Devices on the SCSI bus
16..17:	Devices connected to the primary IDE interface
18..19:	Devices connected to a secondary IDE interface
20..23:	Additional IDE devices
24..63:	Extensions as defined in the pun field in the PUN_INFO structure
64:	Devices on the standard floppy controller
65..255:	Extensions outside the scope of AHDI.

minor:

Minor Device Number (for `major' 0..15: LUN of the ACSI or SCSI device), maximal 255.

key:

A 16-bit key, returned by XHReserve, or 0 if the device is not locked or if the key is unknown

Notation:

Numerical values are, when not specified otherwise, decimal. Hex values (base 16) are introduced by a dollar sign (0x).