(12) United States Patent ao) Patent No.: us 6,539,460 B2
Castelli et al. (45) Date of Patent: Mar. 25,2003
(54) SYSTEM AND METHOD FOR STORING
DATA SECTORS WITH HEADER AND
TRAILER INFORMATION IN A DISK
CACHE SUPPORTING MEMORY
(75) Inventors: Vittorio Castelli, Croton-on-Hudson,
NY (US); Peter A. Franaszek, Mt.
Kisco, NY (US); Philip Heidelberger,
Cortlandt Manor, NY (US); John T.
Robinson, Yorktown Heights, NY (US)
(73) Assignee: International Business Machines Corporation, Armonk, NY (US)
( * ) Notice: Subject to any disclaimer, the term ol this patent is extended or adjusted under 35 U.S.C. 154(b) by 29 days.
(21) Appl. No.: 09/765,563
(22) Filed: Jan. 19, 2001
(65) Prior Publication Data
US 2002/0099907 Al Jul. 25, 2002
(51) Int. CI.7 G06F 12/00
(52) U.S. CI 711/154; 711/112; 711/114;
(58) Field of Search 711/104, 111,
711/112, 144, 170, 173, 118, 154; 710/68
(56) References Cited
U.S. PATENT DOCUMENTS
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* cited by examiner
Primary Examiner—Do Hyun Yoo
Assistant Examiner—Ngoc V Dinh
(74) Attorney, Agent, or Firm—Scully, Scott, Murphy & Presser; Derek S. Jennings, Esq.
A computing system includes a storage server having a memory organization that includes a compressed memory device for storing sectors, each sector having a sector data portion and associated header and trailers, either attached by the hosts or by components ol the computing system. The compressed memory device comprises a memory directory and a plurality ol fixed-size blocks. The system implements a methodology for detaching headers and trailers from sectors before storing the sectors in the memory, and storing the headers and trailers in the memory disk cache, separate from the sector data portion; and, reattaching headers and trailers to sector data portions when the sectors are sent from the memory to a host or to a mass storage device. The header and trailer data are managed through the same memory directory used to manage the compressed main memory. The process ol detaching headers and trailers from sectors for separate storage results in increased efficacy ol data compression, thus yielding better compression ratios, and decreased memory traffic generated by host reads, host writes, cache stages and cache destages.
41 Claims, 17 Drawing Sheets