Electrical computers and digital data processing systems: input/ – Intrasystem connection – Bus access regulation
Patent
1996-07-01
1999-11-02
Sheikh, Ayaz R.
Electrical computers and digital data processing systems: input/
Intrasystem connection
Bus access regulation
711146, G06F 1300
Patent
active
059788747
ABSTRACT:
Snooping is implemented on a split transaction snooping bus for a computer system having one or many such buses. Circuit boards including CPU or other devices and/or distributed memory, data input/output buffers, queues including request tag queues, coherent input queues ("CIQ"), and address controller implementing address bus arbitration plug-into one or more split transaction snooping bus systems. All devices snoop on the address bus to learn whether an identified line is owned or shared, and an appropriate owned/shared signal is issued. Receipt of an ignore signal blocks CIQ loading of a transaction until the transaction is reloaded and ignore is deasserted. Ownership of a requested memory line transfers immediately at time of request. Asserted requests are queued such that state transactions on the address bus occur atomically logically without dependence upon the request. Subsequent requests for the same data are tagged to become the responsibility of the owner-requestor. A subsequent requestor's activities are not halted awaiting grant and completion of an earlier request transaction. Processor-level cache changes state upon receipt of transaction data. A single multiplexed arbitration bus carries address bus and data bus request transactions, which transactions are each two-cycles in length.
REFERENCES:
patent: 5191649 (1993-03-01), Cadambi et al.
patent: 5732244 (1998-03-01), Gujral
Fenwick, D.M., et al., "The AlphaSaver 800 Series: High-End Server Platform Development," Digital Technical Journal, 7(1):43-65 (1995).
Galles, M., "The Challenge Interconnect: Design of a 1.2 GB/s Coherent Multiprocessor Bus," Silicon Graphics Computer Systems Brochure (Jul. 12, 1993) pp. 1.1.1-1.1.7.
Sindhu, P., et al., "HDBus: A High-Performance, Consistent, Packet-Switched VLSI Bus," to appear in Compcom (Spring 1993), San Francisco (Feb. 1993).
Agarwal Nalini
Broniarczyk David
Cerauskis Frederick M.
Cheung Gerald
Hagersten Erik
Sheikh Ayaz R.
Sun Microsystems Inc.
Wiley David A.
LandOfFree
Implementing snooping on a split-transaction computer system bus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Implementing snooping on a split-transaction computer system bus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Implementing snooping on a split-transaction computer system bus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2150594