Mr. Robert Marco Tomasulo

A computer scientist and the inventor (in 1967) of the Tomasulo algorithm, a computer architecture hardware algorithm for dynamic scheduling of instructions that allows out-of-order execution, designed to efficiently utilize multiple execution units. He was the recipient of the 1997 Eckert?Mauchly Award, "for the ingenious Tomasulo algorithm, which enabled out-of-order execution processors to be implemented." The major innovations of Tomasulo algorithm include register renaming in hardware, reservation stations for all execution units, and a common data bus (CDB) on which computed values broadcast to all reservation stations that may need them. These developments allow for improved parallel execution of instructions that would otherwise stall under the use of scoreboarding or other earlier algorithms. He joined IBM research in 1956 after graduating from Manhattan College in New York City, New York. After nearly a decade gaining broad experience in a variety of technical and leadership roles, he transitioned to mainframe development, including the IBM System/360 Model 91 and its successors. Following his 25 year career with IBM, he worked on an incubator project at Storage Technology Corporation to develop the first CMOS-based mainframe system. He co-founded NetFrame, a mid-80s startup, to develop one of the earliest microprocessor-based server systems; and worked as a consultant on processor architecture and microarchitecture for Amdahl Consulting. On January 30, 2008, he spoke at the University of Michigan College of Engineering about his career and the history and development of out-of-order execution.