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Browse Prior Art Database

Dynamic Validation of a Large Virtual Partition Space

IP.com Disclosure Number: IPCOM000080361D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Huang, CC: AUTHOR

Abstract

For a system with various optionally system generated functions and system space requirements, it is difficult to predetermine and preallocate the total validated virtual storage required at an early stage of system initialization. Initializing resident programs and data, or allocating system space for such a system usually requires a large virtual partition to satisfy storage requirements, so that no restriction of system function size or limitation of options will be set.

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Dynamic Validation of a Large Virtual Partition Space

For a system with various optionally system generated functions and system space requirements, it is difficult to predetermine and preallocate the total validated virtual storage required at an early stage of system initialization. Initializing resident programs and data, or allocating system space for such a system usually requires a large virtual partition to satisfy storage requirements, so that no restriction of system function size or limitation of options will be set.

This algorithm allows a virtual storage system to initialize an extremely large virtual partition, without requiring all the page tables to address the entire virtual partition space at system initialization. The virtual partition space required is dynamically validated as needed, an important consideration for systems with limited real storage. The technique also reduces the real storage requirements for building the page tables, and avoid the over-commitment of real pages at system initialization.

Fig. 1 describes the logic flow necessary to accomplish the virtual address space validation. In order to run in dynamic address translation (DAT) mode, the system initializes the control registers and the entire segment table. Initially, only the virtual storage of the top few segments are validated to address the required pageable nucleus and system functions, and most of the Virtual=Real (V=R) space are fixed and mapped one-to-one to the real storage which contains the basic nucleus of the system. (See Fig. 2.)...