Browse Prior Art Database

Request for Storage Hierarchy

IP.com Disclosure Number: IPCOM000077180D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Bidwell, AW: AUTHOR [+3]

Abstract

Employing a request log reduces the amount of request traffic flowing in a storage hierarchy and avoids the allocation and reservation of memory space, until such time as the requested data is actually available for insertion into that space.

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Request for Storage Hierarchy

Employing a request log reduces the amount of request traffic flowing in a storage hierarchy and avoids the allocation and reservation of memory space, until such time as the requested data is actually available for insertion into that space.

When a processor 10 requests data from a local store 12 and the data is not present, a signal is transmitted to a scanner 14. The signal is a multibit signal which identifies the data being requested by its virtual address and the requesting processor 10. The scanner first transmits the signal to the transmit control unit 16 of first storage level 18. The transmit control unit then determines whether the data is stored in the first storage level 18 by interrogating the control map circuitry 20 for the first storage level, and also determines if the data had been previously requested by interrogating the request log 22 for the first storage level. If the data is in the first storage level (whether or not the data had been previously requested), the location of the requestor is added to the request already in request log 22 and a request for data transmittal to local store 12 is made to the transmit control unit, which will honor this request at its earliest convenience. In the request log 22 at the first level, the virtual address and requestor are added to the request log. The requestor's identity is used to pass the data to the proper sink once the request can be fulfilled from this level.

If the data is not present in the first level storage...