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Optimized Save Procedure Using Physical Disk Addresses

IP.com Disclosure Number: IPCOM000047245D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Crowley, TR: AUTHOR [+2]

Abstract

The IBM System/38 has a virtual memory in the form of a single level store where the main storage and disk enclosure storage are treated as a single-level storage space. The System/38 Control Program Facility (CPF) program provides utilities to save and restore user libraries, objects, and basic system information required by CPF for system operation. To save all of the data on the disk enclosures, the user must perform many separate save operations. These CPF utilities run concurrently with normal system operations and compete for system resources. A major disadvantage of the CPF utilities is that access paths are not saved. An access path provides a logical organization to the data base file.

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Optimized Save Procedure Using Physical Disk Addresses

The IBM System/38 has a virtual memory in the form of a single level store where the main storage and disk enclosure storage are treated as a single-level storage space. The System/38 Control Program Facility (CPF) program provides utilities to save and restore user libraries, objects, and basic system information required by CPF for system operation. To save all of the data on the disk enclosures, the user must perform many separate save operations. These CPF utilities run concurrently with normal system operations and compete for system resources. A major disadvantage of the CPF utilities is that access paths are not saved. An access path provides a logical organization to the data base file. If it becomes necessary to restore, CPF must restore all the user libraries, objects, and data bases, and then rebuild the access paths. If many different paths exists, the process of rebuilding them is very time consuming. Instead of using CPF utilities for the save/restore function, an Auxiliary Storage Save/Restore (ASR) process is provided which reads and saves all the data from each of the disk enclosures comprising the system single-level store. The important difference between CPF and the ASR process is that the ASR process will read each disk enclosure by sequential physical disk address. The concept of reading all the data on the disk enclosure by physical disk address minimizes disk head movement. Disk head movement typically requ...