System Control Blocks

Offset
16 (10)
11 (11)
18 (12)
19 (13)
Byte and
Alignment
1
o (0) n
1
. . . 1
. . . 1
m
UNIT CONTROL BLOCK DEVICE EXTENSION BLOCKS
Field
Field Description, Contents, Meaning
Byte 1 X-
0001 0001 -1
0001 0010 -2
Byte 2
Byte 3
0001 0000 10
Byte 4
0000 1010 OA
0000 1011 OB
UCBSNSXT
3210 Display System Devices
3284 and 3286 Printer Extension
Model Code.
Model 1.
Model 2.
No optional features.
Device Class.
Graphics.
Unit Type.
3284 Printer.
3286 Printer.
366 OS System Control Blocks (Release 21.1)
.t:nd of the 3284 and 3286 Printer Extension
UCB Sense Extension
This extension is pointed to by the UCBSNADR field of
the UCB, and is not contiguous to the UCB.
Sense information. The length n is the value in
UCBNBRSN.
Reserved. The length m is the number of bytes needed
to fill out the extension to a fullword boundary. to
fill out the extension to a fullword boundary.