SCSI-message parity error handling during data phase
OwnerSimon Pelly, Neil Johnsoninventors
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Abstract
There is disclosed a method and apparatus for affecting recovery from an inappropriate message received on a SCSI bus, immediately after a data transfer phase. Where a message parity error message is received by a SCSI peripheral device immediately after a data transfer phase, or interrupting a data transfer phase, the peripheral device recognizes the message parity error message as a no-operation message, and re-initiates a full data transfer from the host device.
Claims9
A method of operation of a SCSI enabled device, said method comprising the steps of:
- receiving a message parity error message over a SCSI bus;
- determining whether said SCSI enabled device is in a data transfer state;
- if said SCSI enabled device is in a data transfer state, then generating a response message to an initiator, said response message notifying said initiator device that a previous data transfer operation will be recommenced.
A method of operating a SCSI driver, said method comprising the steps of:
- carrying out a data transfer phase;
- receiving a message parity error message following said data transfer phase;
- and
- sending a restore data pointer message, after receiving said message parity error message.
A SCSI enabled device, comprising:
- means for receiving a message parity error message over a SCSI bus;
- means for determining whether said SCSI enabled device is in a data transfer state;
- and
- means for generating a response signal to an initiator device from which a data transfer phase was initiated, said response message notifying said initiator device that a previous data transfer operation will be recommenced.
A SCSI driver comprising:
- means for carrying out a data transfer phase;
- means for receiving a message parity error message following said data transfer phase;
- means for recognising that a message parity error message has occurred immediately after a data transfer phase;
- and
- means for sending a restore data pointer message, after receiving said message parity error message.
Program data for instructing a processor to perform SCSI operations said operations comprising:
- determining whether a SCSI message parity error message has been received;
- determining whether said device is in a data transfer state;
- if said device is in data transfer state, generating a response message, said response message for notifying a SCSI initiator device that a previous data transfer operation is to be recommenced.
Dependencies are inferred from the claim text.