Browse Prior Art Database

Forward and Backward Referenced Associative Search Mechanism

IP.com Disclosure Number: IPCOM000091553D
Original Publication Date: 1968-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Boland, LJ: AUTHOR

Abstract

The drawing shows an organization of storage arrays to effect an associatively-addressed Data Buffer. The latter is a local copy of the contents of some groups of core memory. All memory fetches attempt to fetch from the Data Buffer. If the operand is not contained in the Data Buffer, Core Memory is selected. An operand group which contains the desired operand is transmitted from Core Memory to the Data Buffer. Store operations are executed into Core Memory and also into the Data Buffer if the operand is contained in it. Directory Array This array contains an 8-bit byte for each group of double-words within the Effective Address spectrum. A group is composed of 32 double-words. There are 16K groups in the Memory spectrum. The 8-bit byte points forward to a physical group location in the Data Buffer.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Page 1 of 3

Forward and Backward Referenced Associative Search Mechanism

The drawing shows an organization of storage arrays to effect an associatively-addressed Data Buffer. The latter is a local copy of the contents of some groups of core memory. All memory fetches attempt to fetch from the Data Buffer. If the operand is not contained in the Data Buffer, Core Memory is selected. An operand group which contains the desired operand is transmitted from Core Memory to the Data Buffer. Store operations are executed into Core Memory and also into the Data Buffer if the operand is contained in it. Directory Array This array contains an 8-bit byte for each group of double-words within the Effective Address spectrum. A group is composed of 32 double-words. There are 16K groups in the Memory spectrum. The 8-bit byte points forward to a physical group location in the Data Buffer. Back Reference Array This array contains a 14-bit byte for each physical group of data contained in the Data Buffer. Up to 256 groups can be contained in the Data Buffer. Each 14-bit byte represents the Effective Address of the group in the physical group location of the Data Buffer. The byte points backward to the Effective Address in the Directory Array. Activity Map This array contains a 1-bit byte for each physical group in the Data Buffer. Whenever a physical group is referenced, the bit for the group is set on. Relative activity among the physical groups can be measured by sensing these bits. Whenever a physical group in the Data Buffer needs to be acquired, the Activity Map gives a good choice for a replaceable group.

The Effective Address tries to translate into a physical group address. If the addressed Directory Array byte contains a nonzero, the Data Buffer contains the desired data in the physical group addressed by the Directory Array byte. If the Directory Array byte is a zero, the Activity Map is interrogated to point to a physical group of the Data Buffer to be...