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:
Apr. 21, 2009
Filed:
Sep. 18, 2006
Giora Biran, Zichron-Yaakov, IL;
Luis E. DE LA Torre, Austin, TX (US);
Bernard C. Drerup, Austin, TX (US);
Jyoti Gupta, Austin, TX (US);
Richard Nicholas, Pflugerville, TX (US);
Giora Biran, Zichron-Yaakov, IL;
Luis E. De la Torre, Austin, TX (US);
Bernard C. Drerup, Austin, TX (US);
Jyoti Gupta, Austin, TX (US);
Richard Nicholas, Pflugerville, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A direct memory access (DMA) device is structured as a loosely coupled DMA engine (DE) and a bus engine (BE). The DE breaks the programmed data block moves into separate transactions, interprets the scatter/gather descriptors, and arbitrates among channels. The DE and BE use a combined read-write (RW) command that can be queued between the DE and the BE. The bus engine (BE) has two read queues and a write queue. The first read queue is for 'new reads' and the second read queue is for 'old reads,' which are reads that have been retried on the bus at least once. The BE gives absolute priority to new reads, and still avoids deadlock situations.