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Algorithm for Memory Allocation

IP.com Disclosure Number: IPCOM000076492D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Grossman, DD: AUTHOR

Abstract

This is an improvement to the memory allocation procedure utilized in the IBM System 360 operating system (OS/360). The OS/360 process operates as follows: control blocks describing free storage space are chained in address order. Then, allocation of space is provided from the first block of storage represented on the chain which can satisfy the request.

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Algorithm for Memory Allocation

This is an improvement to the memory allocation procedure utilized in the IBM System 360 operating system (OS/360). The OS/360 process operates as follows: control blocks describing free storage space are chained in address order. Then, allocation of space is provided from the first block of storage represented on the chain which can satisfy the request.

The algorithm modifies the process as follows: When the request is for a small amount of storage, a search of the chain of available storage is made in ascending address order similar to the OS/360. However, when the request is for a large amount of storage, the chain of available storage space is searched backwards from the end in descending order.

For the purpose of more specifically defining what is meant by small and large storage request, let L(o) be a fixed cutoff parameter. If the request is less than L(o), it is defined as a small core request, and if it is greater or equal to L(o), then it is defined as a large core request.

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