Disk array controller with connection path formed on connection request queue basis

A disk array controller comprising:

• first interface units to a host computer;
• second interface units to a plurality of disk drives;
• a cache memory unit for temporarily storing data to be stored in the disk drives or data stored in the disk drives;
• and
• a selector unit provided between said first and second interface units and said cache memory unit,
• wherein said selector unit comprises:
• a plurality of first ports to be connected to said first and second interface units;
• a plurality of second ports to be connected to said cache memory unit;
• and
• means for connecting, if a first connection request for one port A of the second ports is issued from any one of the first ports, thereafter a second connection request for the port A is issued from any one of the first ports, and thereafter a third connection request for another port B different from the port A of the second ports is issued from any one of the first ports, the port A to the port from which the first connection request was issued, and the port B to the port from which the third connection request was issued.

A disk array controller comprising:

• first interface units to a host computer;
• second interface units to a plurality of disk drives;
• a cache memory unit for temporarily storing data to be stored in the disk drives or data stored in the disk drives;
• and
• a selector unit provided between said first and second interface units and said cache memory unit,
• wherein said selector unit comprises:
• means for connecting a plurality of input ports from said first and second interface units to a plurality of output ports to said cache memory unit;
• means for storing connection requests from said input ports to said output ports in an arrival order of the connection requests;
• and
• arbitor means for arbitrating a plurality of connection requests and assigning an output port to a connection request from an input port, said arbitor means:
• assigns, if a top connection request among the connection requests stored in the arrival order is a connection request to a vacant output port, the output port to the connection request;
• checks a second connection request, if the top connection request among the connection requests stored in the arrival order is a connection request to an occupied output port, and assigns, if the second connection request is a connection request to a vacant output port, the output port to the second connection request;
• checks a third connection request, if the second connection request is a connection request to an occupied output port, and thereafter repeats an assignment of an output port to a connection request at the most by several times equal to the number of vacant output ports.