udsc.equ

与MS-DOS兼容的DOS操作系统

;    File              : $UDSC.EQU$
;
;    Description       :
;
;    Original Author   : DIGITAL RESEARCH
;
;    Last Edited By    : $CALDERA$
;
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UDSC_BPB_LENGTH	equ	25

UDSC		struc
UDSC_NEXT	dd	?		; link to next UDSC_
UDSC_RUNIT	db	?		; ROS drive number (0/1/80/81)
UDSC_DRIVE	db	?		; logical drive
UDSC_BPB	db	UDSC_BPB_LENGTH dup (?)	; current BPB
UDSC_FATFLAG	db	?
UDSC_OPNCNT	dw	?		; # of files open on drive
UDSC_TYPE	db	?		; floppy drive type (0/1/2/7)
UDSC_FLAGS	dw	?		; various flags for drive
UDSC_NCYL	dw	?		; # of cylinders per drive
UDSC_DEVBPB	db	UDSC_BPB_LENGTH dup (?)	; device BPB
		db	7 dup (?)
UDSC_TIMER	dw	2 dup (?)	; tick count for MEDCHK
UDSC_LABEL	db	12 dup (?)	; ASCIIZ volume label
UDSC_SERIAL	dd	?		; serial number
UDSC_FSTYPE	db	9 dup (?)	; ASCIIZ "FAT12"/"FAT16" type
UDSC		ends

UDSC_LENGTH	equ	size UDSC

UDF_HARD	equ	0001h		; drive is a hard disk
UDF_CHGLINE	equ	0002h		; drive support disk change line
UDF_UNSURE	equ	0004h		; drive has just been formatted
UDF_VFLOPPY	equ	0010h		; drive shares physical drive
UDF_OWNER	equ	0020h		; logical drive "owns" physical drive
UDF_MEDIA	equ	0100h		; media id is from bootsec, not default

MAXPART		equ	26		; support up 26 drives