A proposal to establish a pseudo virtual memory via writable overlays

ABSTRACT

Many computer systems solve executable storage size problems for large programs by using overlays. However, it appears that no one overlay scheme contains a well-balanced combination of the most useful capabilities which are found in various existing techniques. A proposal is presented which utilizes several of the best capabilities from existing schemes and is complemented by several additional features, e.g. writable overlays. The writable overlay capability provides a virtual memory effect, although the programmer may still be required to design the overlay configuration. Since overlay structuring is a complex task, several tools (including a graphic display) are included in the proposal in order to aid the programmer in the design. The content of overlays is briefly discussed, and it is noted that many of the details of the final overlay configuration may be decided after the fact.

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INDEX TERMS

Keywords:
collector, folding, linkage editor, loader, overlay, overlay structure, paging, segment, segmentation, virtual memory