Abstract: A computer I/O system which includes a dynamic switch having a plurality of ports and a plurality of link-level facilities, with each link-level facility being attached to an individual one of the ports. Whenever the state of a port or its attached link-level facility is changed in such a way that the attached link-level facility's ability to communicate with another link-level facility might be affected, this fact is recognized by a dynamic switch control unit which causes a state change notification (SCN) frame to be transmitted to all other link-level facilities which might be affected. The link-level facilities receiving such a state change notification then determine if any of the associations or potential associations with the link-level facility which caused the state change notification are affected.

Abstract: A computer interconnection system provides dynamic switch cascading with a plurality of circuit switches having circuit switch ports coupled by a dynamic connection to provide a dynamically cascadable switching network having a plurality of nodes, including end point and switch nodes. Two individual circuit switches of the network are interconnected by a cross-link group of one or more links. The system transmits frame information including a source endpoint address and a destination endpoint address, each of which can be associated with an endpoint port or a cross-link group, and forms a connection between an endpoint port or a cross-link group to make a connection between a circuit switch port corresponding to a source endpoint address and a circuit switch port corresponding to the destination endpoint.

Abstract: An inexpensive and low power consumption power control unit that does not require a separate interface or network. In the power off state only a detector and a power controller require power, this power is supplied from a power source. Upon detection of traffic a frame decoder is powered up to receive frames. When the link is quiet, the decoder is powered down while the power controller and receiver remain powered and await further traffic.

Abstract: A computer system, including at least one host (processor and operating system), a channel subsystem and at least one switch (together with an associated switch controller) for switchably connecting an I/O device (together with an associated I/O device control unit) to a host via said channel subsystem, in combination with means for dynamically managing I/O connectivity in said computer from each host. The I/O manager's functions are centralized at the host level across the computer system. Each host is responsible for an instance of the manager.

Abstract: A dynamic switch and its protocol for establishing dynamic connections in a link by the use of frames, each frame having an identification of the source of the frame, an identification of the destination of the frame for the requested connection, and link controls to maintain, initiate or terminate a connection between the source and the destination. The frames are bounded by a start of frame delimiter and an end of frame delimiter which may also act as a connect link control and a disconnect link control, respectively, and the connections are made through the dynamic switch having dynamic-switch ports. The state of a dynamic-switch port is changed dependent on its present state, the dynamic connection requested, and the direction and type of frames passing through the dynamic-switch port.