Browse Prior Art Database

Dynamic Address Translation Extension

IP.com Disclosure Number: IPCOM000085734D
Original Publication Date: 1976-May-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Alvarez, JA: AUTHOR

Abstract

A solution is proposed to the problem in IBM System/370 Dynamic Address Translation where two users desire to access the same page of virtual storage. The solution requires that the user be given direct and expeditious access to portions of a number of virtual spaces without having to go to the supervisor program.

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Dynamic Address Translation Extension

A solution is proposed to the problem in IBM System/370 Dynamic Address Translation where two users desire to access the same page of virtual storage. The solution requires that the user be given direct and expeditious access to portions of a number of virtual spaces without having to go to the supervisor program.

The number of segments to which a user can have direct access is determined by the number of "segment registers" available to the user. The segment registers allow the user's virtual space to be defined as a composite of segments from many virtual spaces, which can be loaded by the user from a predefined set of segment descriptors such that access to a large number of segments is possible.

Each segment register contains the information required to access one segment of virtual space. The required information includes the segment table address, the size of the segment, the address of the page table associated with the segment, the size of the page, and a validity bit. The segment registers are ordered and present a profile of a user's virtual space at any point and time.

All segments which the user has a need to access are specified in a predefined Segment Register Table in main storage. The user is given access to the segment register table through an instruction defined to load the user's segment registers from the segment register table. The segment register table is established by the supervisor program and the u...