Digital Equipment Corporation

Ajai Thirumalai

William F Bruckert

Thomas D Bissett

Jay Amirmokri

A process for transferring data via DMA between a system resource and a controller via switching logic. During a setup write transaction, the switching logic is set up to enable DMA data to be transferred between a particular system memory and a selected system resource. The setup write transaction also is used to initialize the DMA byte counter. During a subsequent write transaction, DMA pointer registers are initialized with appropriate starting addresses. The controller then transmits a DMA start code and the system resource responds by transmitting an acknowledge code. At that time, DMA data is transmitted between the controller and the system resource via the switching logic.

Protocol for transfer of DMA data

A process for transferring information including a source or destination address between two nodes in a network via data switching logic. The switching logic must decode commands and addresses in order to adopt the proper configuration so that the commands and addresses can be forwarded from one system resource to another system resource. A read or write address is transmitted to the switching logic and decoded in order to configure the switching logic. The same read or write address is then retransmitted to the switching logic for forwarding to the appropriate system resource. As a result, there is no need for extra storage logic in order to retain read and write addresses while the switching logic is being configured.

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Marlboro, MA, United States of America

Ajai Thirumalai