51 lines
1.9 KiB
PHP
51 lines
1.9 KiB
PHP
|
BREAK <DPB structure>
|
|||
|
|
|
|||
|
|
;
|
|||
|
|
; Microsoft Confidential
|
|||
|
|
; Copyright (C) Microsoft Corporation 1991
|
|||
|
|
; All Rights Reserved.
|
|||
|
|
;
|
|||
|
|
|
|||
|
|
;** DPB - Drive Parameter Block
|
|||
|
|
;
|
|||
|
|
; BUGBUG - this isn't authorative - it's my probably incomplete and
|
|||
|
|
; possibly inaccurate deductions from code study... - jgl
|
|||
|
|
;
|
|||
|
|
; The DPB is DOS's main structure for describing block devices.
|
|||
|
|
; It contains info about the "Drive" intermingled with info about
|
|||
|
|
; the FAT file system which is presumably on the drive. I don't know
|
|||
|
|
; how those fields are used if it's not the FAT file system - BUGBUG
|
|||
|
|
;
|
|||
|
|
; The DPBs are statically allocated and chained off of DPBHead.
|
|||
|
|
; Users scan this chain looking for a match on DPB_DRIVE.
|
|||
|
|
; The DPBs are built at init time from info in the SYSDEV structure.
|
|||
|
|
|
|||
|
|
|
|||
|
|
DPB STRUC
|
|||
|
|
|
|||
|
|
DPB_DRIVE DB ? ; Logical drive # assoc with DPB (A=0,B=1,...)
|
|||
|
|
DPB_UNIT DB ? ; Driver unit number of DPB
|
|||
|
|
DPB_SECTOR_SIZE DW ? ; Size of physical sector in bytes
|
|||
|
|
DPB_CLUSTER_MASK DB ? ; Sectors/cluster - 1
|
|||
|
|
DPB_CLUSTER_SHIFT DB ? ; Log2 of sectors/cluster
|
|||
|
|
DPB_FIRST_FAT DW ? ; Starting record of FATs
|
|||
|
|
DPB_FAT_COUNT DB ? ; Number of FATs for this drive
|
|||
|
|
DPB_ROOT_ENTRIES DW ? ; Number of directory entries
|
|||
|
|
DPB_FIRST_SECTOR DW ? ; First sector of first cluster
|
|||
|
|
DPB_MAX_CLUSTER DW ? ; Number of clusters on drive + 1
|
|||
|
|
DPB_FAT_SIZE DW ? ; Number of records occupied by FAT
|
|||
|
|
DPB_DIR_SECTOR DW ? ; Starting record of directory
|
|||
|
|
DPB_DRIVER_ADDR DD ? ; Pointer to driver
|
|||
|
|
DPB_MEDIA DB ? ; Media byte
|
|||
|
|
DPB_FIRST_ACCESS DB ? ; This is initialized to -1 to force a media
|
|||
|
|
; check the first time this DPB is used
|
|||
|
|
DPB_NEXT_DPB DD ? ; Pointer to next Drive parameter block
|
|||
|
|
DPB_NEXT_FREE DW ? ; Cluster # of last allocated cluster
|
|||
|
|
DPB_FREE_CNT DW ? ; Count of free clusters, -1 if unknown
|
|||
|
|
|
|||
|
|
DPB ENDS
|
|||
|
|
|
|||
|
|
DPBSIZ EQU SIZE DPB ; Size of the structure in bytes
|
|||
|
|
|
|||
|
|
DSKSIZ = DPB_max_CLUSTER ; Size of disk (temp used during init only)
|
|||
|
|
|