switch the channels of one processor to the other processor. The channel set
switching instructions that the control program can use to connect and disconnect a
channel set to a processor are:CONCS DISCS connect channel aet disconnect channel set
Note: When you generateVM/SP as an MP system it does not use the channel set
switching facility even if the facility is installed on the hardware.
Advantages of the AP IMP Environment
AnAP IMP environment provides additional processing capability when compared
to a uniprocessor environment. An APIMP environment also provides increased
availability. In case of hardware malfunction on one processor, the other processor
can frequently continue operating. Serviceability is enhanced because it is possible
to use the VARYON/OFF PROCESSOR command to vary a processor offline for
system repair or to upgrade the system.
Facilitating an AP IMP EnvironmentI Prefixing
In anAP or MP environment, two processors share main storage. To facilitate this
sharing,VM/SP provides for the unique features and requirements of this envi
ronment: prefixing, processor address identification, processor signaling,
time-of-day clock synchronization, interlocks on certain fetch and store
instructions, locks, and affinity setting. The system programmer should be familiar
with the instructions used to accomplish these tasks.
WhenVM/SP is executing in an AP IMP environment both processors cannot use
absolute page zero for status information. Instead, each processor has its own pre
fixed storage area(PSA) in the high end of real storage. However, if the system
operator varies a processor online afterCP initialization completes, the processor's PSA may be located in any page of the dynamic paging area. See Figure 29 on
page210 for a storage map of the V=R machine after CP initialization. CP in Attached Processor and Multiprocessor Modes 209
switching instructions that the control program can use to connect and disconnect a
channel set to a processor are:
Note: When you generate
switching facility even if the facility is installed on the hardware.
Advantages of the AP IMP Environment
An
to a uniprocessor environment. An AP
availability. In case of hardware malfunction on one processor, the other processor
can frequently continue operating. Serviceability is enhanced because it is possible
to use the VARY
system repair or to upgrade the system.
Facilitating an AP IMP Environment
In an
sharing,
ronment: prefixing, processor address identification, processor signaling,
time-of-day clock synchronization, interlocks on certain fetch and store
instructions, locks, and affinity setting. The system programmer should be familiar
with the instructions used to accomplish these tasks.
When
absolute page zero for status information. Instead, each processor has its own pre
fixed storage area
operator varies a processor online after
page