IBM 801
Encyclopedia
The 801 was an experimental minicomputer designed by IBM. The resulting architecture was used in various roles in IBM until the 1980s. The 801 was started as a pure research project led by John Cocke
in October 1975 at the Thomas J. Watson Research Center
. The name 801 comes from the building the project was housed in, number 801. IBM was looking for ways to improve performance of its existing machines, with project team members studying traces of programs running on System/370
mainframes and looking at the compiler code. From this project came the idea that it was possible to make a very small and very fast core, which could then be used to implement the microcode
for any machine.
The project subsequently developed the 'fast core' design as a CPU, also called the 801. The resulting CPU was operational by the summer of 1980 and was implemented using Motorola MECL-10K technology on large wire wrapped custom boards. The CPU was clocked at 66 ns cycles (approximately 15.15 MHz) and could compute at the then-fast speed of approximately 15 MIPS. This prototype design was a 24-bit implementation without virtual memory
. The 801 architecture was used in a variety of IBM devices including channel controllers for their S/370 mainframes, various networking devices, and eventually the IBM 9370 mainframe core itself.
In the early 1980s the lessons learned on the 801 were put back into the new America Project, which led to the IBM POWER
architecture and the RS/6000
deskside scientific microcomputer.
John Cocke
later won both the Turing award
and the Presidential Medal of Science for his work on the 801.
John Cocke
John Cocke was an American computer scientist recognized for his large contribution to computer architecture and optimizing compiler design. He is considered by many to be "the father of RISC architecture."...
in October 1975 at the Thomas J. Watson Research Center
Thomas J. Watson Research Center
The Thomas J. Watson Research Center is the headquarters for the IBM Research Division.The center is on three sites, with the main laboratory in Yorktown Heights, New York, 38 miles north of New York City, a building in Hawthorne, New York, and offices in Cambridge, Massachusetts.- Overview :The...
. The name 801 comes from the building the project was housed in, number 801. IBM was looking for ways to improve performance of its existing machines, with project team members studying traces of programs running on System/370
System/370
The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...
mainframes and looking at the compiler code. From this project came the idea that it was possible to make a very small and very fast core, which could then be used to implement the microcode
Microcode
Microcode is a layer of hardware-level instructions and/or data structures involved in the implementation of higher level machine code instructions in many computers and other processors; it resides in special high-speed memory and translates machine instructions into sequences of detailed...
for any machine.
The project subsequently developed the 'fast core' design as a CPU, also called the 801. The resulting CPU was operational by the summer of 1980 and was implemented using Motorola MECL-10K technology on large wire wrapped custom boards. The CPU was clocked at 66 ns cycles (approximately 15.15 MHz) and could compute at the then-fast speed of approximately 15 MIPS. This prototype design was a 24-bit implementation without virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
. The 801 architecture was used in a variety of IBM devices including channel controllers for their S/370 mainframes, various networking devices, and eventually the IBM 9370 mainframe core itself.
In the early 1980s the lessons learned on the 801 were put back into the new America Project, which led to the IBM POWER
IBM POWER
POWER is a reduced instruction set computer instruction set architecture developed by IBM. The name is an acronym for Performance Optimization With Enhanced RISC....
architecture and the RS/6000
RS/6000
RISC System/6000, or RS/6000 for short, is a family of RISC and UNIX based servers, workstations and supercomputers made by IBM in the 1990s. The RS/6000 family replaced the IBM RT computer platform in February 1990 and was the first computer line to see the use of IBM's POWER and PowerPC based...
deskside scientific microcomputer.
John Cocke
John Cocke
John Cocke was an American computer scientist recognized for his large contribution to computer architecture and optimizing compiler design. He is considered by many to be "the father of RISC architecture."...
later won both the Turing award
Turing Award
The Turing Award, in full The ACM A.M. Turing Award, is an annual award given by the Association for Computing Machinery to "an individual selected for contributions of a technical nature made to the computing community. The contributions should be of lasting and major technical importance to the...
and the Presidential Medal of Science for his work on the 801.
External links
- The evolution of RISC technology at IBM by John Cocke – IBM Journal of R&D, Volume 44, Numbers 1/2, p.48 (2000)
- The 801 Minicomputer - An Overview
- IBM System 801 Principles of Operation, Version 2
- 801 I/O Subsystem Definition