Single pipe non-blocking architecture

A bridge coupled between a host and a target, the target having a storage management component and a separately accessible disk command queue, the bridge comprising:

• a command FIFO used to temporarily store incoming commands from the host;
• a timer;
• and
• a processor configured to:
• determine if the incoming command is a data command or a management command;
• processing management commands separately from data commands, including:
• forward the incoming command to the storage management component of the target when the incoming command is a management command;
• when the incoming command is a data:
• determine if a disk command queue on the target is full;
• send the incoming command to the disk command queue when the disk command queue is not full;
• when the disk command queue is full:
• start a timer, the timer having a predetermined length;
• send the incoming command to the disk command queue when the disk command queue becomes not full prior to the expiration of the timer;
• and
• send a rejection of the incoming command to the host only if, upon expiration of the timer, if the disk command queue is still full;
• wherein the predetermined length of the time is selected to reduce a performance penalty for the host to process rejections of incoming data commands when there is a temporary disk command queue full state.

An apparatus for processing an incoming command from a host at a bridge, the incoming command destined for a target, the target having a storage management component and a separately accessible disk command queue, the apparatus comprising:

• means for determining if the incoming command is a data command or a management command;
• means for processing management commands separately than data commands, including:
• means for forwarding the incoming command to the storage management component of the target when the incoming command is a management command;
• means for, when the incoming command is a data command:
• determining if a disk command queue on the target is full;
• sending the incoming command to the disk command queue when the disk command queue is not full;
• when the disk command queue is full:
• starting a timer, the timer having a predetermined length;
• sending the incoming command to the disk command queue when the disk command queue becomes not full prior to the expiration of the timer;
• and
• sending a rejection of the incoming command to the host only if, upon expiration of the timer, if the disk command queue is still full;
• wherein the predetermined length of the time is selected to reduce a performance penalty for the host to process rejections of incoming data commands when there is a temporary disk command queue full state.

A non-transitory program storage device readable by a machine tangibly embodying a program of instructions executable by the machine to perform a method for processing an incoming command from a host at a bridge, the incoming command destined for a target, the method comprising:

• determining if the incoming command is a data command or a management command;
• processing management commands separately than data commands, including:
• forwarding the incoming command to a storage management component of the target when the incoming command is a management command;
• when the incoming command is a data command:
• determining if a disk command queue on the target is full;
• sending the incoming command to the disk command queue when the disk command queue is not full;
• when the disk command queue is full:
• starting a timer, the timer having a predetermined length;
• sending the incoming command to the disk command queue when the disk command queue becomes not full prior to the expiration of the timer;
• and
• sending a rejection of the incoming command to the host only if, upon expiration of the timer, if the disk command queue is still full;
• wherein the predetermined length of the time is selected to reduce a performance penalty for the host to process rejections of incoming data commands when there is a temporary disk command queue full state.