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Module Packing in a Virtual Memory Environment Disclosure Number: IPCOM000084857D
Original Publication Date: 1976-Jan-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 3 page(s) / 37K

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This is a method for determining optimum module placement patterns in a virtual storage system.

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Module Packing in a Virtual Memory Environment

This is a method for determining optimum module placement patterns in a virtual storage system.

An area of virtual space, e.g., the link pack area (LPA) of OS/VS2, contains pageable shared system and installation modules involved in intermodule linkages. This module packing algorithm or analyzer is essentially a problem program that may be initiated at any time to monitor the intermodule linkage activity occurring in the system, and produce lists which govern placement of modules in a page or a series of pages at system initialization time.

Once started, the structure of the existing nonoptimized area is analyzed to determine the name, location and size of each module residing in the area. After the structure of the pageable area has been determined, the next phase of the algorithm is to monitor and record all the linkage activity within the system. The trace record of collected data is then sorted into a series of linkage sequences timeordered on a per-task basis.

After the sorted trace of linkage system activity is established, then affinity values are assigned to the modules in each sequence. For example, if the intermodule linkage sequence A--> B--> C --> D --> E --> P is observed, then the affinity of A to B (A,B) is X(1). Similarly, A also has an affinity for C (A,C). Since A does not go directly to C, but must first invoke B, the affinity (A,C) is less than (A,B) and is expressed as X(2), where X(2) is smaller than X(1).

If affinities are considered to be significant to a depth of 5, then in a linkage sequence A --> B--> C--> D--> E--> F -->G, affinities between A and B, C, D, E, and F would be considered and arbitrarily assigned values based upon the proximity of each linkage, e.g., (A,B)=5; (A,C)=4; (A,D)=3; (A,E)=2; (A,F)=1.

An (n) x (n) affinity ma...