Browse Prior Art Database

Dumping Real Storage Under OS/VS Release 2

IP.com Disclosure Number: IPCOM000079383D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 29K

Publishing Venue

IBM

Related People

Rathjen, JC: AUTHOR

Abstract

I. BACKGROUND. For OS/VS2 Release 2, the concept of virtual address spaces was developed to release a job from storage confinements and fear of interference from other jobs. Each job runs in its own virtual address space.

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Dumping Real Storage Under OS/VS Release 2

I. BACKGROUND.

For OS/VS2 Release 2, the concept of virtual address spaces was developed to release a job from storage confinements and fear of interference from other jobs. Each job runs in its own virtual address space.

A virtual address space is a large block of virtual storage with virtual addresses ranging from 0 - 16 million. Each virtual address space contains a common area and a private area, and has the same range of virtual addresses (0 - 16 million). The common area is the same for each virtual address space. The private area is different and is protected from other virtual address spaces. That is, a job running in virtual address space A can reference data in the common area and in his own private area, but cannot reference data in the private area of any other virtual address space.

Virtual address spaces share real storage; while many virtual address spaces may be in real storage at the same time, a complete virtual address space will probably never be in real storage. Only those parts of a virtual address space necessary to execute the next instruction are in real storage. When instructions are executing in real storage, the virtual addresses of the virtual address space are translated to the real addresses of real storage that the parts of the virtual address space currently occupy.

If another part of the virtual address space is needed to execute the next instruction, it will be brought into real storage from a secondary storage device and assigned a real-storage location. Likewise, when a part of a virtual address space is no longer needed, it will be saved on a secondary storage device for future use, freeing up the real-storage location.
II. PROBLEM.

If an error occurs in a virtual address space, a dump program, running under the control program, may dump those parts of the virtual address space needed to debug or service the problem. If data, currently on a secondary storage...