received by
(2314/2319,
selected in the following manner:
1. CP tries to allocate a space on the cylinder at which the arm on
the selected device is currently positioned.
2. If slots are not available on the current cylinder, CP tries to
allocate space on a cylinder for which paging
3. If the above conditions cannot be
to the center of the volume as is possible.
Before
on the device is
a device, the paging channel programs are slot-sorted and chained
PAGING
spooling pages.
channel programs, expands the compressed slot addresses, and maintains a
queue of
calls
In either case, all that needs to be passed to
address of the CORT1BLE entry for the page that is to be .oved, the
address of a
code, and the address of a
dispatching after the
necessary I/O, and uses the device code that is part of the page address
to index into the syste.'s
the
rotational position sensing, the required sector is computed and a
proper device.
primary
is unstacked to the interruption return address, waitpage, in
then stacks the queued
which they were received. The address of the real page
into the appropriate page table entry and the pointers denoting the
ownership of the real page fraae are filed into the
the processing routines in
the related page fraae, the
and the dispatcher,
activates the pending task. The error recovery followed depends on the
operation being perforaed. Paging
operations are discussed in
CP Introduction 1-113