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:
Jan. 04, 2000
Filed:
Nov. 03, 1997
Reinhard C Schumann, Stow, MA (US);
Yong S Oh, Belmont, MA (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A memory controller for optimizing direct memory access (DMA) read transactions wherein a number of cache lines are prefetched from a main memory as specified in a prefetch length field stored in a page table. When all prefetch data has been fetched, the memory controller waits to determine whether the initiator of the DMA read transaction will request additional data. If additional data is needed, additional cache lines are fetched. Once the initiator terminates the DMA read transaction, the prefetch length field for a selected page other entry in the table is updated to reflect the actual DMA read transaction length. As a result, an optimum number of cache lines are always prefetched thereby reducing the number of wait states required.