Method and system for un-tagged command queuing

A system for processing tagged commands from a Fibre Channel host in a Fibre Channel network to one or more target devices through a SCSI router, comprising:

• instructions for receiving a command in the SCSI router from a Fibre Channel host for an intended one of the one or more target devices;
• instructions for determining whether the command is a tagged command;
• if the command is a tagged command, instructions for converting the command's format to an un-tagged command format if the intended one of the one or more target devices is a streaming target device;
• and
• instructions for forwarding the command to the intended one of the one or more target devices.

A method for processing multiple commands to a streaming target device through a SCSI router in a Fibre Channel network having a plurality of Fibre Channel hosts, comprising the steps of, in the SCSI router:

• creating a FIFO queue;
• receiving a first command from one of the plurality of Fibre Channel hosts;
• if the first command is a tagged command, converting the command's format to an un-tagged format;
• forwarding the first command to the streaming target device;
• processing a subsequent command from one of either said one of the plurality of Fibre Channel hosts or from one of other ones of the plurality of Fibre Channel hosts, comprising:
• (a) receiving the subsequent command in the SCSI router;
• (b) if the subsequent command is a tagged command, converting the command's format to an untagged format
• (c) determining whether the streaming target device has completed execution of the first command;
• (d) if the streaming target device has completed execution of the first command, forwarding the subsequent command to the streaming target device;
• (e) if the streaming target device has not completed executing the first command, placing the subsequent command in the FIFO queue;
• and
• (f) forwarding the subsequent command from the FIFO queue to the streaming target device upon completion of the first command by the streaming target device;
• and
• repeating the step of processing a subsequent command from one of either said one of the plurality of Fibre Channel hosts or said one of other ones of the plurality of the second Fibre Channel hosts for at least one additional subsequent command, wherein the subsequent command is the first command and the at least one additional subsequent command is the subsequent command.

A method for processing commands to a sequential access target device (“SATD”) through a SCSI router in a Fibre Channel network having a plurality of Fibre Channel hosts, comprising the steps of, in the SCSI router:

• (a) receiving a command from one of the plurality of Fibre Channel hosts;
• (b) if the command is a tagged command, converting the command's format to an un-tagged format;
• (b) if the command requires a transfer of data larger than a threshold size, streaming the data to the SATD;
• and
• (c) if the command requires a data transfer smaller than the threshold size, storing the data in one or more memory buffers as they become available and forwarding the data to the SATD.

A method for processing commands to a sequential access target device (“SATD”) through a SCSI router in a Fibre Channel network having a plurality of Fibre Channel hosts, comprising the steps of, in the SCSI router:

• (a) receiving a command from one of the plurality of Fibre Channel hosts;
• (c) if the command is a tagged command, converting the command's format to an un-tagged format;
• (b) if the command requires a data transfer larger than a threshold size, streaming the data from the SATD;
• and
• (c) if the command requires a data transfer smaller than the threshold size, storing the data in one or more memory buffers as they become available and forwarding the data to the Fibre Channel host that issued the command.