In
<CAE1XxDEE02g1BCOv-2Utmz+3abtMGxSdD=A8bub-nJXHXY=3...@mail.gmail.com>,
on 06/22/2012
at 08:26 AM, John Gilmore <[email protected]> said:
>RESERVE is not a special form of ENQ. It was then and is now
>hardware implemented.
Wrong again. There is a RESERVE macro, going back to the early days of
OS/360, and it is a special form of ENQ. The fact that there is also a
Reseve CCW opcode does not change that.
63.0 RESERVE -- Reserve a Device (Shared DASD)
63.1 Description
The RESERVE macro reserves a device for use by a particular system;
it
must be issued by each task needing to reserve a device shared with
one or
more systems. The RESERVE macro protects the caller from
interference by
other tasks in the system and locks out other systems. The reserve
actually occurs when the first I/O is done to the device after the
RESERVE
macro is issued. When the reserving program no longer needs the
reserved
device, it should issue a DEQ macro to release the resource.
--
Shmuel (Seymour J.) Metz, SysProg and JOAT
Atid/2 <http://patriot.net/~shmuel>
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)
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