System Control Blocks

offset
-36 (-24) 4
-32 (-20) 4
-28 (-lC) 4
-24 (-18) 4
-20 (-14) 4
-36 (-24) 4
-32 (-20) 4
-28 (-lC) 4
-24 (-18) 4
-20 (-14) 4
-i6 (-iO; i
-15 (-F) • 7
-8 (-8) 4
-4 (-4) 1
-3 (-3) • 3
Bytes and Field
Alignment Name
(End of
Extent)
(Start I/O)
(PCI)
(Channel
End)
(Abnormal
End)
DEBEOEA
DEBSIOA
DEBPCIA
DEBCEA
DEBXCEA
DEBWKARA
DEBDSCBA
DEBDCBMK
DEBLNGTH
DATA EXTENT BLOCK -- ORDINARY
Field Description, Contents, Meaning
APPENDAGE TABLE
BSAM, QSAM, BPAM, BDAM, GAM
Address of the end-of-extent appendage routine.
Address of the start I/O appendage routine.
Address of the program-controlled-interruption
appendage routine.
Address of the channel-end appendage routine.
Address of the abnormal-end appendage routine.
BTAM, QTAM MESSAGE CONTROL
Address of the end-of-extent appendage routine.
Address of the start I/O appendage routine.
Address of the program-controlled-interruption
appendage routine.
Address of the channel-end appendage routine.
Address of the abnormal-end appendage routine.
END OF APPENDAGE TABLE
PREFIX SECTION
DIRECT-ACCESS STORAGE DEVICES
I/O support work area.
DSCB address (BBCCHHR) used by I/O support.
ALL DEVICES
DCB modification mask used by I/O support.
Length of DEB in double words.
Reserved.
DEB 119