SCSI - handling of I/O scans to multiple LUNs during write/read command disconnects
OwnerSimon Pelly, Neil Johnsoninventors
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Abstract
There is disclosed a method of handling of I/O scans to multiple logical unit numbers used to identify individual peripheral devices on a small computer system interface, wherein a peripheral device, upon receiving an inquiry command, checks whether a write/read I/O command is outstanding, if a write/read I/O command is outstanding, sets a delay flag delaying said peripheral device for a predetermined period of time; on expiry of said delay time, initiates a data transfer with the host device.
Claims13
A method of operating a peripheral device enabled to communicate using a small computer system interface protocol, said method comprising:
- receiving a SCSI command write/read signal;
- receiving a SCSI inquiry signal;
- in response to receipt of said received SCSI command write/read signal and said received SCSI inquiry signal, causing said peripheral device to delay initiating a response to the SCSI inquiry signal for a predetermined time period.
A tape data storage device comprising:
- a tape drive mechanism for accepting a removable tape data storage media for storage of data;
- at least one buffer memory for temporarily storing data to be read to said tape data storage media and to be written from said tape data storage media;
- a small computer system interface driver;
- a controller device for controlling said buffer memory, said tape drive mechanism and said small computer system interface driver;
- wherein said tape data storage device operates to:
- receive a SCSI command write/read signal;
- receive a SCSI inquiry signal;
- in response to receipt of said received SCSI command write/read signal and said received SCSI inquiry signal, cause said peripheral device to delay initiating a response to the SCSI inquiry signal for a predetermined time period.
A driver for operating a small computer system interface enabled peripheral device enabled to communicate with at least one other SCSI enabled device according to the SCSI protocol, said driver comprising:
- means for receiving a SCSI command write/read signal;
- means for receiving a SCSI inquiry signal;
- and
- a delay timer;
- wherein in response to receipt of said received SCSI command write/read signal and said received SCSI inquiry signal, said driver causes said peripheral device to delay initiating a response to the SCSI inquiry signal for a predetermined time period.
A system of computer entities, communicating via a small computer system interface, said system comprising:
- at least one host computer entity;
- at least one target computer entity;
- said system operating such that:
- arbitration is initiated by the target entity, to select the host computer and commencement of data transfer between the host computer and target entity can occur during a bus free period comprising the inquiry period of an inquiry initiated by said host computer to said target entity.
Program data comprising program instructions for causing a processor to operate a small computer system interface (SCSI) protocol driver, said driver operating to:
- receive a SCSI command write/read signal;
- receive an SCSI enquiry signal;
- in response to receipt of said received SCSI command write/read signal and said received SCSI inquiry signal, set a delay timer to extend for a predetermined time period;
- and
- on expiry of said time period, respond to said SCSI enquiry.
A driver for operating a small computer system interface enabled peripheral device enabled to communicate with at least one other SCSI enabled device according to the SCSI protocol, said driver operable to:
- receive SCSI command write/read signal;
- receive a SCSI inquiry signal;
- and
- a delay timer;
- wherein in response to receipt of said received SCSI command write/read signal and said received SCSI inquiry signal, said driver operates to cause said peripheral device to delay initiating a response to said SCSI inquiry signal for a predetermined time period.
Dependencies are inferred from the claim text.