A system and method are described for enforcing the validity of circulating pointers stored in a pointer FIFO (first-in-first-out) memory. One or more target pointers are generated and compared to circulating pointers. If a pointer does not circulate through the system within a pre-specified time, then a pointer has been lost and an error is reported. If a circulating pointer matches a target pointer, it is suppressed by being removed from the set of circulating pointers. Another timer is then set to determine whether further circulating pointers match a target pointer. If so, then multiple pointers to the same location are present and all duplicate pointers are suppressed. After expiration of the second time, the target pointers are added to the set of circulation pointers. This process repeats with new target pointers, so that the validity of the set of circulating pointers is verified.

A queuing system that avoids live-locking is provided. A representative implementation of this system 1) selects a first queue item pointed to by a rotating pointer if the first queue item is ready to be serviced, 2) selects a second queue item pointed to by a find-first-pointer if the first queue item is not ready to be serviced, and 3) updates the rotating pointer so that the rotating pointer points to a third queue item.

A computer system having a plurality of processing nodes interconnected by a message transfer network. Each node includes an instruction processor, a transmit circuit to transmit messages to other processing nodes through the message transfer network and a plurality of postings in a memory storage. Each message includes a header part and a data part with the header part having distinguishing fields that are used to distinguish messages. Each posting includes message specification fields corresponding to each distinguishing field of a message header part wherein the message specification fields selectively matching the distinguishing fields of a message. Each posting further includes a posted control field wherein the posted control field is used to control the operation of a receive circuit with respect to a message matching the posting. The receive circuit enables receiving of messages sent by other processing nodes through the network, searching upon reception of each message for and locating a posting having message specification fields that match the corresponding distinguishing fields of the message being received and to control upon location of a posting, the posted control field to control the operation of the receive circuit with respect to the message being received.

Aspects for preventing deadlock in a log structured array are described. In an exemplary method aspect, and system for providing same, the method includes monitoring available segments to determine when to reserve an open segment, identifying a process type requesting access to the open segment, and limiting access to one process type for the reserved segment. Limiting access further includes limiting access to a garbage collection process.

A method and apparatus for delivering multimedia video data from a server (host processor) to a plurality of clients connected to a communications network. More specifically, with this invention, preprocessed video and multimedia data packets are stored in switches of the network. When a client desires to receive the video and multimedia data, sends a request to the host processor which in turn sends a control message to the switches storing the requested data. These switches in turn send the requested data to the requesting client. If the data is not stored in the switches, the data must then be forwarded directly from the server to the requesting client.