Patent ID: 6076128
Filing Date: 2000-06-13
Classification: G06F

Abstract:
A method for transferring data between buses, in a data processing system that has a first bus, a second bus interconnected with said first bus through a first bridge device, and a third bus interconnected with said second bus through a second bridge device, with devices on said second bus using addresses within a predetermined address space and devices on the other buses using addresses outside said predetermined address area, comprising the steps of:(a) a device on said second bus issuing a request to access a device on said third bus;(b) said first bridge device acknowledging and transmitting said access request to said first bus;(c) said first bridge device, when no acknowledgement of said access request is issued by any device on said first bus, storing an address of a device to be accessed and terminating said access request;(d) said device on said second bus retrying said access request;(e) said first bridge device comparing an address of a device to be accessed to said stored address and ignoring said access request when said addresses match; and(f) said second bridge device, when no acknowledgement of said access request is issued by any device on said second bus, acknowledging and transmitting said access request to said third bus.