Format-7 DSCB

Common Name:: Format 7– –VTOC Data Set Control Block
Owning Component:: DADSM (DF107)
Eye-catcher ID:: X'07070707'
Subpool and Key:: Not applicable
Size:: 140 bytes.
Pointed to by:: The CCHHR address of the first format-7 DSCB is contained in the DS4EFPTR field of the format-4 DSCB.
Function:: Extent description for certain devices

Offset	Type/Value	Len	Name (Dim)	Description
0 (0)	CHARACTER	4	DS7KEYID	KEY IDENTIFIER (X'07070707')
SPACE FOR 5 F7 ENTRIES
4 (4)	CHARACTER	40	DS7EXTNT	SPACE FOR 5 EXTENT DESCRIPTIONS
44 (2C)	CHARACTER	1	DS7FMTID	FORMAT IDENTIFIER (X'F7')
SPACE FOR 11 F7 ENTRIES
45 (2D)	CHARACTER	88	DS7ADEXT	SPACE FOR 11 EXTENT DESCRIPTIONS
133 (85)	CHARACTER	2		RESERVED
DESCRIPTION OF THE F7 FORWARD POINTER
135 (87)	CHARACTER	5	DS7PTRDS	POINTER (CCHHR) TO NEXT FORMAT 7 DSCB OR ZERO
135 (87)		*	DS7CCPTR	TWO BYTES OF CYLINDER DATA (CC)
		*	DS7HHPTR	TWO BYTES OF HEAD DATA (HH)
		*	DS7RPTR	ONE BYTE OF RECORD DATA (R)
		*	DS7END	END OF THE DSCB 7 MAPPING
SINGLE FORMAT 7 RTA EXTENT DESCRIPTION EACH FORMAT 7 ENTRY HAS THE FOLLOWING FORMAT: BYTES 0-3 START RTA ADDRESS BYTES 4-7 END RTA ADDRESS + 1
	CHARACTER	8	DS7EXT	DESCRIPTION OF ONE F7 EXTENT DESCRIPTION ENTRY
	CHARACTER	4	DS7RTAST	STARTING RTA VALUE
	CHARACTER	4	DS7RTAED	ENDING RTA VALUE + 1