Format of DOS 4.0+ data segment subsegment control blocks

[ Back ] [ Next ]

Offset

Size

Description

00h

BYTE

subsegment type (blocks typically appear in this order)

"D"	device driver
"E"	device driver appendage
"I"	IFS (Installable File System) driver (MS-DOS 7) high-loaded drive data table array (see #02603)
"F"	FILES=	control block storage area (for FILES>5)
"X"	FCBS=	control block storage area, if present
"C"	BUFFERS EMS workspace area (if BUFFERS /X option used)
"B"	BUFFERS=	storage area
"L"	LASTDRIVE=	current directory structure array storage area
"S"	STACKS=	code and data area, if present (see #01634,#01635)
"T"	INSTALL=	transient code

01h

WORD

paragraph of subsegment start (usually the next paragraph)

03h

WORD

size of subsegment in paragraphs

05h

3 BYTEs

unused

08h

8 BYTEs

for types "D" and "I", base name of file from which the driver was loaded (unused for other types)