International Business Machines Corporation

Robert G Iseminger

James Wilson Bishop

George A Fax

Richard Allen Kelley

Douglas R Chisholm

Wan Lin Leung

James T Moyer

Mark C Snedaker

A programmable timing circuit on an integrated circuit chip for testing the cycle time of functional circuits on the chip. The timing circuit includes a selectable input having at least two sources, one of which is a toggle circuit; a minimally delayed control path including a control latch; a programmable delay path in parallel with the control path and including a sample latch; and a comparator for comparing the state of the control latch and sample latches to provide a signal indicative of the delay path being longer than the control path. A plurality of configuration latches and multiplexers are provided for selecting the input source and routing an input signal through specific delay blocks to control the amount of delay in the delay path.

Programmable timing circuit for testing the cycle time of functional circuits on an integrated circuit chip

In a computer system, a plurality of input/output processors (IOP's) are connected via an asynchronous input/output bus, called an 'SPD' bus, to one side of an input/output interface controller (IOIC). The other side of the IOIC is connected to a storage controller (SC) via a synchronous bus called an 'adapter' bus. The SC is connected to a common system memory and possibly also to an instruction processing unit. The IOIC comprises at least one shared DMA facility for executing DMA read/write storage operations requested by the IOP's via the SPD bus. Each shared DMA facility includes a buffer for holding control information and data to be transmitted between the SC and one of the IOP's. This enables the SPD bus to be released for utilization by otehr IOP's connected thereto during periods of 'storage latency' that occur after a DMA storage operation has been initiated by one IOP.

Method and apparatus for increasing system throughput via an

Growing community of inventors

Vestal, NY, United States of America

Robert G Iseminger