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:
Nov. 03, 2009
Filed:
Nov. 20, 2003
James C. Chen, Tucson, AZ (US);
Minh-ngoc L. Huynh, San Jose, CA (US);
Matthew J. Kalos, Tucson, AZ (US);
Chung M. Fung, San Francisco, CA (US);
James C. Chen, Tucson, AZ (US);
Minh-Ngoc L. Huynh, San Jose, CA (US);
Matthew J. Kalos, Tucson, AZ (US);
Chung M. Fung, San Francisco, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Methods, system and computer program product are provided to improve the efficiency of data transfers in a PPRC environment. Any or all of three features may be implemented, each of which reduces the number of round trips required for the exchange of handshaking, data and control information. A first feature includes disabling the 'transfer ready' acknowledgment which normally occurs between a primary storage controller and a secondary storage controller. A second feature includes pre-allocating payload and data buffers in the secondary storage controller. A third feature includes packaging write control information with a write command in an extended command descriptor block (CDB). Such a step eliminated the need for a separate transmission of the write control information. The CDB is transmitted along with a data block from the primary storage controller to the secondary storage controller and placed in the respective, pre-allocated buffers. Data may also be pipelined to the secondary. By decreasing the response time for data transfers, the distance separating the primary and secondary storage controllers may be increased.