Abstract: A method and system to verify the passage of one or more write commands sent from an originating location through a PCI bus system. An addressable data storage is located substantially at the end of the PCI bus system with respect to the originating location. A write command is sent by the originator subsequent to the one or more write commands, to a predetermined special end location address identifying the addressable storage. The command is accompanied by data comprising a predetermined special return address at the originating location. The PCI bus system transmits the write commands on a FIFO basis, so the one or more write commands precede the subsequently sent write command. Logic senses the subsequently sent write command, and responds to the command, sending a return echo write command to the predetermined special return address. The returning echo write command verifies the passage of the write commands and data through the PCI bus system.

Abstract: In a PCI bus system, a method and system check for errors in rite data transferred from a PCI data source across a PCI bus to the PCI bus system, the data comprising a plurality of blocks. Redundancy calculation logic receives the write data across the PCI bus, calculates a check value for each block of the data transferred across the PCI bus, and updating any previously calculated check value with the calculated check value at a storage location of a storage memory. Data path logic is coupled to the PCI bus and to the storage memory, and responds to a unique identifier of a redundancy write command sent subsequent to completion of the transfer of the write data across the PCI interface. The data path logic responds to the write command unique identifier, detecting the updated calculated check value at the storage location of the storage memory.

Abstract: To exchange a digital data input stream, a transmitter sends the digital data input stream to a receiver, and the receiver sequentially divides the stream into different interleaved substreams and later combines the substreams to provide an output including the original digital data input stream. The original digital data input stream includes multiple subgroups of data, such as bytes. Each subgroup is stored in a selected buffer of the receiver. Buffers are selected in a predetermined order of rotation to store sequentially received subgroups. Thus, each buffer receives subgroups in a defined order. Later, each buffer outputs its stored subgroups in the same order as received. A data assembler assembles the subgroups output by the various buffers, reconstructing the original digital input stream.

Abstract: To exchange a digital data input stream, a transmitter sends the digital data input stream to a receiver, and the receiver sequentially divides the stream into different interleaved substreams and later combines the substreams to provide an output including the original digital data input stream. The original digital data input stream includes multiple subgroups of data, such as bytes. Each subgroup is stored in a selected buffer of the receiver. Buffers are selected in a predetermined order of rotation to store sequentially received subgroups. Thus, each buffer receives subgroups in a defined order. Later, each buffer outputs its stored subgroups in the same order as received. A data assembler assembles the subgroups output by the various buffers, reconstructing the original digital input stream.

Abstract: A data storage system is described which allows data storage devices with different characteristics, such as differing data rates and transfer speeds, to be connected, and intermixed, along a single data and communication link. The data storage system comprises a storage controller, a first data storage device, a second data storage device, and a data and communication link coupled therebetween. The storage controller transfers data to and from the first data storage device using data locations within the data and communication link to transfer a data byte, a parity location to transfer the associated parity bit, and a communication signal location to transfer a data clocking signal. The storage controller further transfers data to and from the second data storage device using the data locations to transfer a data byte and the parity location to transfer a data clocking, or a data strobe, signal.

Abstract: A device controller is described within a data storage system for pre-fetching device work information from multiple data storage devices, and accumulating the device work information to immediately respond to a subsequent device poll command from a storage controller. The device controller includes a device receiver to receive the device poll command, a device transmitter to transmit a response to the device poll command, a device information register for storing the pre-fetched device work information for each data storage device, and a sequencer for periodically pre-fetching the device work information from each data storage device. The sequencer pre-fetches such information by verifying that no device subsystem command from the storage controller is pending in the device receiver, then issuing a background poll command to a selected device to query the device for its device work information, and storing the device work information in the device information register.

Abstract: A data transfer system providing parity uses a method and apparatus for transmitting a data clocking signal in a parity bit location along a data bus to latch an accompanying data byte at a receiving device. A transmitting device, coupled to the receiving device through the data bus, generates a data clock signal and latches the clock signal into the parity bit location of the data bus. The clock signal and data byte are then transmitted along the data bus to the receiving device. The receiving device uses the clock signal to latch the data byte from the data bus. Thus, the data transfer system uses the data clock signal transmitted in the parity bit location of the data bus to validate and synchronize the accompanying data byte at the receiving device.