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Memory Relocation

IP.com Disclosure Number: IPCOM000095570D
Original Publication Date: 1964-Mar-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Ang, WS: AUTHOR [+2]

Abstract

This computer system provides for a computer memory hard protection (neither read nor write) and relocation, and soft protection (read only) within a part of the relocated area. In the computer, memory protect register P stores high-order bits to be compared in comparator CR with corresponding high-order bits in memory address register M. The required capacity of P is dependent on the memory design and, in the example, is seven.

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Memory Relocation

This computer system provides for a computer memory hard protection (neither read nor write) and relocation, and soft protection (read only) within a part of the relocated area. In the computer, memory protect register P stores high-order bits to be compared in comparator CR with corresponding high-order bits in memory address register M. The required capacity of P is dependent on the memory design and, in the example, is seven.

Compare register C controls the number of bits actually compared, seven, and, depending upon the outcome, a decision is made whether or not to abort the store cycle, thus preventing data, stored in the locations accessible through the designated high-order bits, from being destroyed. Relocation and hard protection are accomplished by altering certain high order bits in a sought address stored in address register Y. Thus, the program is caused to operate in an area other than originally specified and preventing it from accessing information stored outside of the relocated area.

In control switch CS, the number of high-order bits specified in R are replaced in Y by corresponding bits of P, to set up the relocated address in M (see CS operation table). Comparator CR compares the bits from P specified by C, here seven, with corresponding bits from M (see CR operation table). A decision is then made whether or not to abort the store cycle (soft protection). In the example of the drawing, the following memory arrangement resul...