The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 23, 1997
Filed:
May. 23, 1995
James Thomas Brady, San Jose, CA (US);
Alden B Johnson, Los Gatos, CA (US);
John Chi-Shing Lui, Shatin, HK;
Jaishankar Moothedath Menon, San Jose, CA (US);
Shin-Yuan Tzou, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and means are disclosed in a Log Structure Array (LSA) storage subsystem for managing said subsystem without a need for an access to a complete LSA directory in a RAM. This object is achieved by maintaining (1) a subset of the LSA directory (referred to as LSA sub-directory) in a RAM where the LSA sub-directory comprises the logical track address of a predetermined number of most recently accessed logical tracks; (2) a journal of changes to the LSA directory which is maintained on a different power boundary than the LSA directory power boundary; and, (3) an array of bit maps, one bit map per segment which is used for fast garbage collection thus eliminating the need for having an access to a complete LSA directory in a RAM during garbage collection.