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Hex Dec Type/Val Lng Label (dup) Comments
---- ---- --------- ---- -------------- --------
0000 0 Structure RSHBK RSPBK Header Block
0000 0 Signed 4 RSHCOUNT Count of number of RSPBKs
0004 4 Address 4 RSHANCH Pointer to first RSPBK
Notes : There will be three versions of the RSHBK present on
any system. One will represent the head of the reader
RSPBKs, one will represent the head of the printer
RSPBKs and one will represent the head of the punch
RSPBKs. They will be anchored in SYSCM at SYSRDRT,
SYSPRTT and SYSPUNT, respectively.
No attempt should be made to acquire the lock
represented by RSHLOCK while an RDEV lock is held.
Furthermore, if more than one of these locks needs
to be acquired, they should be acquired in the order
of reader, printer and punch and released in the
oppposite order to prevent possible dead-locks.
These locks may be acquired by threads that are holding
an RDEV lock.
0008 8 Dbl-Word 8 RSHLOCK (3) Lockwords used by HCPLCK to allow
us to manipulate RSPBK chains
0020 32 Signed 4 * Reserved for future IBM Use
0024 36 Signed 4 * Reserved for future IBM Use
00000028 RSHBKLEN *-RSHBK Length of RSHBK area
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