Storage Control Unit Channel Communication
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Speed of connection of a channel to a storage device control unit in a contention environment is enhanced by moving the point of contention inboard of the control unit from the channel interface. (Image Omitted) A normal multi-channel storage control unit is shown in Fig. 1, having a plurality of channel interfaces 10 controlled by a channel switch 11, each interface 10 connected to an independent channel 12. The channel switch 11 and the command and data transfer logic 13 can service only one channel interface at a time. Therefore, the control unit transmits "Control Unit Busy" status at the interface to each of the other channel interfaces. When the control unit completes a task, it transmits a "Control Unit End" status to all channels, which scan for pending work and restart the I/O operation.