Astronautics ZS-1
RICM Online Computer Crypt - Astronautics ZS-1, S/N 005, ca. 1986
Articles on this machine:
Lecture 1 Early ILP Processors and Performance Bound Model
ZS-1 Demonstrator “Annette”
In the 1980’s the Astronautics Corporation of America maintained a research facility in Madison, Wisconsin in the former Queen of Apostles Seminary where the ZS-1 super mini computer was developed. the Pallottine Fathers decided to close the school in 1979. The property was purchased by Nathaniel Zelazo and his sister Norma Paige of Astronautics Corp. of America to continue their space research for the University of Wisconsin.
Zelazo (1918-2018) and Norma Paige (1922-2017) founded Astronautics Corporation of America in 1959. The company makes aircraft navigation aids. The ZS systems claimed a performance of 45 MIPS and 22.5 MFLOPS, with from 32Mb to 1,024Mb memory. The ZS-2 was a dual processor version, and both could be expanded to take up to four CPUs. They ran BSD Unix 4.3 and Sun’s Network File System, The ZS-Series was the result of a four year development project, and the two models – the ZS-1 and ZS-2 – were aimed primarily at the general scientific and engineering applications market. Prices for the ZS Series went from $400,000 to $700,000.
During January 2002 Merle Peirce drove to Wisconsin to retrieve this Astronautics ZS-1 system. Jon Auringer and Andre Boeder of Astronautics, Richard Shauer, Jerry ?, and ?, of the Illinois Railway Museum's Trackless Department, and Dr. Gunter Schadow assisted in loading the equipment in Wisconsin. Dr. James E. Smith, professor at the University of Wisconsin-Madison was involved in the design and took a sabbatical from 1985-1989 to work on the ACA ZS-1 project. The ZS programme had hardly come to fruition when Cray released its EL-98 model which was more popular. As a result, only six ZS-1’s were constructed.
An additional double unit, serial number 7 was probably the ZS-2 prototype. This was scrapped in 2002. One unit was retained for display at the Astronautics general headquarters in Milwaukee, Wisconsin. Serial number 5 was the ZS-1 demonstrator named “Annette” after Mr. Zelazo’s daughter and was given to the Rhode Island Computer Museum. The remaining four units found homes at NASA’s John C. Stennis Space Research Centre in Hancock County, Mississippi, the University of Wisconsin, the University of Michigan and New York University where Norma Paige was a Trustee of the NYU School of Law.
During January 2002 Merle Pierce drove to Wisconsin to retreive this Astronautics ZS-1 system. Jon Auringer and Andre Boeder of Astronautics, Richard Shauer, Jerry ?, and ?, of the Illinois Railway Museum's Trackless Department, and Gunter Schadow assisted in loading the equipment in Wisconsin.
This machine was designed by Dr. James E. Smith when he worked for the Astronautics Corporation of America in Madison, WI. The CPU is DAE (decoupled access/execute) architecture which increases the amount of parallelism and can hide a large amount of memory latency. The CPU provides (a really impressive for the time) 45 MIPS and 22.5 MFLOPS peak, has 64 bit floating point, and 128KBytes of cache. The Interconnect Network has 1.42 GBytes/s bandwidth and the I/O Multiplexer provides an aggregate of 180 MBytes/s of bandwidth. The system supports a maximum of 256 MBytes of 16 way interleaved memory with a bandwidth of 350 MBytes/s.
The decoupled architecture allows the CPU to fetch a maximum of two instructions per 45 ns clock period. The two instructions are split into individual steams and are then processed by its own pipeline. One pipeline containe the "A" instructions and does all of the memory accesses. The other pipeline contains the "X" instructions and does the floating point operations. Several instructions may be in some phase of execution concurently. The access and execution sections are connected with queues. The queues are buffered seperately which allows the access instruction stream to run ahead of the execute instruction stream. This results in a major reduction in memory access time.
The system runs 4.3 BSD UNIX. The Fortran compiler creates code that optimizes the performance of the pipelines. The compiler also unrolls loops to reduce the number of branch instructions that are executed.
This machine, S/N 005, was the first production quality system and is the only ZS-1 that is not in possession of Astronautics.
The RICM also received many spare boards for this system.
The CPU.
Dual SMD Disk Drives.
The Interconnect Network.
The I/O Multiplexor.
The VME based I/O Processor.
Memory.
The Service Processor.