Disk cache management techniques using non-volatile storage

Details Disk cache management techniques using non-volatile storage Disk cache management techniques using non-volatile storage

1993-06-30

1997-06-03

Chan, Eddie P.

395470, G06F 1208

Patent

active

056363559

ABSTRACT:
A method, and apparatus for its use, for reducing the number of disk accesses needed to satisfy requests for reading data from and writing data to a hard disk. A non-volatile cache memory used to hold data blocks for which write requests have been made is purged of "dirty" blocks, not yet written to the disk, based on the proportion of dirty blocks in relation to an upper threshold and a lower threshold. A purge request flag is set when the proportion of dirty blocks goes above the upper threshold, but is not cleared until the proportion of dirty blocks goes below the lower threshold. So long as the purge request flag is set, dirty blocks are purged when the disk is not busy with read requests. Immediate purging is initiated when the write cache becomes totally full of dirty blocks. Purging of dirty blocks is also effected during disk read accesses, by "piggybacking" a writing operation with the reading operation, to write dirty blocks destined for the same track or cylinder in which the requested read data blocks are located.

REFERENCES:
patent: 4603380 (1986-07-01), Easton et al.
patent: 4636946 (1987-01-01), Hartung et al.
patent: 4920478 (1990-04-01), Furuya et al.
patent: 4956803 (1990-09-01), Tayler et al.
patent: 5119485 (1992-06-01), Ledbetter et al.
patent: 5309451 (1994-05-01), Noya et al.
patent: 5353410 (1994-10-01), Macon, Jr. et al.
"The IBM 3990 Disk Cache", Jai Menon, IBM Almaden Research Center, San Jose, California; Mike Hartung, IBM Tucson Laboratory, Tucson, Arizona, pp. 146-151 1988.

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