Siemens U3585-J-Z125-8-76 1 manual Paging I/O operations, Paging memory, Paging rate, Path info

Glossary

The PPC value is again supplied as a measure of how local a task is, but it is less precise here than with task-local management.

The check is made and working set pages are removed only if free page frames are required. This is why UPG may become greater than the working set, especially if the main memory is large. The UPG/PPC relationship which exists in task-local management thus does not apply to global management.

3.Selective management

A combination of both methods is provided by the selective management method for main memory pages. In this case all pages of the tasks are globally managed using the attributes SYSTEM and TP, and all pages of the tasks are managed locally using the attributes DIALOG and BATCH.

A common feature of both methods is that unassigned page frames are kept in a free page pool.

The optimum main memory management algorithm is set automatically, after which it can no longer be influenced by generation parameters or the startup parameter service. The replacement procedure valid at the start of a BS2000 session is SYS-WS.

paging I/O operations

All I/O operations performed in response to paging requests.

paging memory

The whole main memory area available to all users for paging.

paging rate

Number of required paging I/O operations per second (calls to the I/O control module).

path info

A 3-byte address comprising the channel address (2 bytes) and the device address of a complete data path between main memory and the device.

PGE task

System task required for restarting after hardware errors during paging I/O.

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