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:
Dec. 23, 1997
Filed:
Aug. 16, 1996
Vernon J Legvold, Tucson, AZ (US);
Julia Liu, Sunnyvale, CA (US);
Carol S Michod, Tucson, AZ (US);
Chan Yiu Ng, San Jose, CA (US);
William G Sherman, II, Tucson, AZ (US);
Jeffrey R Steffan, San Jose, CA (US);
Steven R Van Gundy, Gilroy, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system and method for changing the number of logical volumes in a drawer in a rack in a direct access storage device subsystem is disclosed. The method and system are able to change the number of logical volumes without disrupting access to the other logical volumes in the rack. Channel connection addresses, which are logical volume addresses as known by the CPUs, are freed by removing the old drawer and then are mused. If the new drawer has more logical volumes than the old drawer, the next unused channel connection addresses are used with the new drawer. In a subsystem having a storage controller for providing control for a plurality of direct access storage devices, the logical volumes are spread across multiple physical devices. The storage controller maintains configuration data for the entire subsystem in redundant, non-volatile storage locations reserved specifically for its use. Each logical volume address for the rack is set by the drawer location and the logical sequence of the volumes within the drawer. As drawers are installed, the control unit sequentially assigns the volume addresses for the control unit and the channel connection addresses for the CPUs.