On Apr 27, 2008, at 11:26 AM, Binyamin Dissen wrote:
How is SRB to TCB percolation instantiated?
Is an automatic FRR added which does the percolation if nothing
recovers?
Stored somewhere in memory?
Its your obligation to initialize it.
In the case of STARTIO, you do it this way:
STARTIO SRB=xxxx,TCB=yyyy (original way)
or
STARTIO SRB=xxxx,TCB=0 (new way)
in the second case, the IECIOSCN grabs the TCB address from PSATOLD.
There are numerous cases where the first (and which was formerly the
only) way is required: when I/O is started from within a process
which itself is run under an SRB, or, possibly, is run in a disabled
interrupt exit (DIE) and for which the TCB and the SRB currently
dispatched are completely arbitrary (taken to mean indeterminate).
In the basic case of a SCHEDULE, the user initializes the field to
associate the SRB with its TCB.
No automatic FRR that I am aware of.
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