Quantum Corporation

Seagate Technology Incorporated

Eric Kvamme

Erhard Theodor Schreck

Michael M Lee

Don Brunnett

Bernhard Hiller

Bruce C Schardt

Maurice L Schlumberger

Chandra Shaker Buddhavaram

David Chew

Pantelis Alexopoulos

Jeffery H Appelbaum

Samuel Richard Duell

Farrokh Mottahedin

Leroy L Leach

Richard Sonnenfeld

Robert L Kimball

Kathleen Fitzgerald, Legal Representative

Robert Milby

Thierry Chatard

Jeff Griffiths

Johanna Hernandez

James McGrath

A RAID system is provided which can be implemented as a hardware RAID system while avoiding certain shortcomings of previous RAID systems. The RAID system makes it possible to avoid or reduce the number of buffers or processors and can take advantage of drive logic to achieve RAID functions or enhancements. RAID functionality can be provided in a manner to accommodate one or more ATA drive interfaces. To avoid drive replacement problems, host requests for drive serial numbers are responded to with a mirror serial number. In one embodiment, the read address is used to select which drive will perform a read operation.

RAID system and method compatible with improved drive select

A cable detection method is provided for detecting the existence of an 80-conductor cable used in connecting a host device to peripheral devices of a computer system. An 80-conductor cable is required for Ultra-ATA to function at data transfer rates of modes 3 or 4. In compliance with ATA/ATAPI standards and requirement, the cable detection method includes the placement of a capacitor on the PDIAG- signal at the host. A device would assert the PDIAG- signal to a low state for a predetermined length of time to discharge the capacitor, release the signal then measure the state of the signal within a window of time, thereby assuring a high state for an 80 conductor cable and a low state for a non-80 conductor cable.

Method for detecting a cable type by utilizing the peripheral device to measure and send a state of the PDIAG-signal to the host

A synchronous DMA burst transfer method is provided for transferring data between a host device and a peripheral drive device connected by an ATA bus. The method provides synchronous data transfer capability in an asynchronous system by having one device in charge of both a strobe signal and a data signal. When a host read or write command is delivered to the peripheral drive device, the peripheral device decides when to start the synchronous DMA burst. For a read command, the peripheral device requests the synchronous DMA burst then drives a data word onto the ATA bus after the host acknowledges that it is ready to begin the burst. After allowing time for the data signal to settle, the peripheral device toggles a strobe signal from a high state to a low state. The host sees the edge of the strobe signal at which time the host latches the data word on the bus. Additional data words can be driven on the bus and the strobe signal can be retoggled to latch the additional data words into the host. After all data words have been transferred, the strobe signal is returned to a high state so that it is ready to be used for another host command. By reducing the hold time of the receiving device and controlling the hold time of the sending device, the method reduces timing delays and provides a data transfer rate up to 66.7 MBytes/sec. The method is easily implemented in existing systems and is backward compatible with existing transfer protocols.

System for increasing data transfer rate using sychronous DMA transfer protocol by reducing a timing delay at both sending and receiving devices

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Scotts Valley, CA, United States of America

Eric Kvamme