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:
May. 05, 1998
Filed:
May. 31, 1996
Timothy C Ng, Cary, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Apparatus for providing slave direct memory access (DMA) support on a computer system bus that does not support slave devices, such as the personal computer interconnect or 'PCI' bus. An adapter card or microprocessor has a local DMA controller that can act as a busmaster and simulate a system DMA controller which would normally be used during slave DMA operations. Alternatively, the local DMA controller can work with an existing system DMA controller so that application software receives the correct status when polling registers in the system DMA controller. The local DMA controller allows the system DMA controller to operate as if the system DMA controller is controlling DMA transfers. In this way device contention between the system DMA controller and the local DMA controller is avoided.