Virtual Memory Hierarchy
Original Publication Date: 1979-Mar-01
Included in the Prior Art Database: 2005-Feb-19
A Virtual Memory Hierarchy (VMH) Image Storage Subsystem for an Image Recognition Unit is shown in the drawing. The subsystem is so named since it requires, as a minimum, two levels of storage with levels two and higher being virtually addressed. The VMH differs from earlier "virtual memories" utilized on processors in several important aspects. The first level of storage acts as more than simply a buffer for the second level of storage. Two additional and significant functions of the first level of storage are1) to provide a filter action of image video to the second level of storage, such that only video pertinent to processing the document is copied down to the second level, and to provide translation and rotation of video signals depending upon the orientation of the images on the source document scanned.