Abstract: Data is transmitted from a sending processor over a network to one or more receiving processor in a forward direction during an allocated slot, and acknowledge signals are sent in a reverse direction during the same allocated slot, to indicate whether the receiving processor is able to receive data If one or more of the receiving processors indicates that it is unable to receive the data, the data is retransmitted during the next allocated slot. This means that the sending processor is able to determine within the slot period whether a retransmission is necessary, but that the slot period only needs to be long enough for one-way communication.

Abstract: An array of processing elements can incorporate a degree of redundancy. Specifically, the array includes one or more spare, or redundant, rows of array elements, in addition to the number required to implement the intended function or functions of the device. If a defect occurs in one of the processors in the device, then the entire row which includes that defective processor is not used, and is replaced by a spare row.

Abstract: There is described a processor architecture having a plurality of processing elements, each element having at least one input port and at least one output port, each port having at least a data bus and a valid data signal line; and a bus structure which contains a plurality of switches which are arranged so as to allow an output port of any first processing element to be connected to the input port of any second processing element for a time interval, in which each processing element is enabled to set a value on the valid data signal line of its output port to a first logic state when the associated data bus contains a transfer value, and to a second logic state when the data bus does not contain a transfer value, and in which each processing element is further enabled to enter a waiting state for a predetermined time interval when the value on the valid data signal line of the associated input port is in the second logic state. This reduces the power consumption of the device.