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Offset<br />
49 (31) • 1<br />
50 (32) •• 2<br />
50 (32)<br />
51 (33)<br />
40 (28) 2<br />
42 (2A) •• 2<br />
44 (2C) 1<br />
45 (2D) • 3<br />
48 (30) 1<br />
Bytes and Field<br />
Alignment Name<br />
DCBIFLG<br />
00 ••<br />
01 ••<br />
11 ••<br />
• .00 00 ••<br />
11 ••<br />
10 ••<br />
01 ••<br />
•• xx<br />
DCBMACR<br />
Byte 1<br />
00 ••<br />
• .1.<br />
• .• 1 1 ••.<br />
.1 ..<br />
Byte 2<br />
00 ••<br />
• .1.<br />
..• 1<br />
• . 1.<br />
• •• 1<br />
1 •••<br />
• x ••<br />
• .1.<br />
•.. 1<br />
DCBTIOT<br />
DCBMACRF<br />
DCBIFLGS<br />
DCBDEBAD<br />
DCBOFLGS<br />
80 OS <strong>System</strong> <strong>Control</strong> <strong>Blocks</strong> (Release 21.7)<br />
DATA CONTROL BLOCK -- BDAM<br />
Field Description, Contents, Meaning<br />
FOUNDATION SEGMENT -- BEFORE OPEN (Continued)<br />
Used by I/O sUfervisor in communicating error<br />
conditions and in determining corrective procedures.<br />
Not in error procedure.<br />
Error correction in process.<br />
Permanent error condition.<br />
Always zeros.<br />
Always use I/O supervisor error routine.<br />
Never use I/O supervisor error routine.<br />
Never use I/O supervisor error routine.<br />
Never use I/O supervisor error routine.<br />
(Reserved bits)<br />
Macro instruction reference.<br />
Major macro instructions and various options<br />
associated with them that will be used.<br />
R<br />
K<br />
I<br />
S<br />
x<br />
C<br />
W<br />
K<br />
I<br />
A<br />
Always zero for BDAM.<br />
READ<br />
Key segment with READ.<br />
ID argument with READ.<br />
<strong>System</strong> provides area for READ (dynamic<br />
buffering>.<br />
Read exclusive.<br />
CHECK macro instruction.<br />
Always zero for BDAM.<br />
WRITE<br />
Key segment with WRITE •<br />
ID argument with WRITE.<br />
Reserved.<br />
Add type of WRITE.<br />
Unblocked spanned records, with BFTEK=R<br />
specified and no dynamic buffering: The user's<br />
program has provided a segment work area pool<br />
and stored the address of the segment work area<br />
control block in DCBDYNB (offset 100).<br />
FUNDATION SEGMENT -- AFTER OPEN<br />
Offset from the TIOT origin to the TIOELNGH field in<br />
the TIOT entry for the DD statement associated with<br />
this DCB.<br />
Contents and meaning are the same as DCBMACR in the<br />
foundation before OPEN.<br />
Contents and meaning are the same as DCBIFLG in the<br />
foundation before OPEN.<br />
Address of the associated DEB.<br />
Note: The above fields overlay the DCBDDNM field<br />
during OPEN and are restored to their original form<br />
at CLOSE.<br />
Contents and meaning are the same as DCBOFLGS in the<br />
foundation before OPEN.
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