Browse Prior Art Database

Resetting Storage Unit Directories

IP.com Disclosure Number: IPCOM000050916D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Benhase, MT: AUTHOR

Abstract

This article describes a storage hierarchy having a data storage unit coupled to a main data storage unit(s) and having data access via hashing circuits and a directory. The directory will have hash-linked lists containing synonyms of the hashing addresses. Also, an LRU (least recently used) doubly-linked list for replacement control is contained in the directory. When the data storage units are reset, the directory is not altered unless the reset occurs during an updating cycle of the directory. When this event occurs, the hash-linked list is erased and reestablished based upon the control information stored in the directory. The LRU doubly linked list is reestablished in an arbitrary basis.

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Resetting Storage Unit Directories

This article describes a storage hierarchy having a data storage unit coupled to a main data storage unit(s) and having data access via hashing circuits and a directory. The directory will have hash-linked lists containing synonyms of the hashing addresses. Also, an LRU (least recently used) doubly-linked list for replacement control is contained in the directory. When the data storage units are reset, the directory is not altered unless the reset occurs during an updating cycle of the directory. When this event occurs, the hash-linked list is erased and reestablished based upon the control information stored in the directory. The LRU doubly linked list is reestablished in an arbitrary basis.

A data storage unit, such as a random-access volatile memory, buffers and caches data between a processor and a backing or main data storage unit(s), which may be either volatile data storage or retentive data storage. Retentive data storage is typically magnetic tape recorders or disk-type apparatus. A directory relates the addresses of the main data storage unit to addresses of the buffer data storage unit. Other control information such as congruency between the copies of data in the two data storage units, pinning controls, and the like, may be included. Accessing the buffer data storage unit requires supplying an address related to the main data storage unit to a hash circuit. The hash circuit generates a hash-class signal identifying a set of main data-storage unit addresses. This hash-class signal goes to a scatter ind...