The ACS-1 and ACS-360 are two related supercomputers designed by
IBM as part of the IBM ''Advanced Computing Systems'' project from 1961 to 1969. Although the designs were never finished and no models ever went into production, the project spawned a number of organizational techniques and architectural innovations that have since become incorporated into nearly all
high-performance computers in existence today. Many of the ideas resulting from the project directly influenced the development of the
IBM RS/6000 and, more recently, have contributed to the
Explicitly Parallel Instruction Computing
Explicitly parallel instruction computing (EPIC) is a term coined in 1997 by the HP–Intel alliance to describe a computing paradigm that researchers had been investigating since the early 1980s. This paradigm is also called ''Independence'' a ...
(EPIC) computing paradigm used by
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...
and
HP in high-performance processors.
History
The ACS project began in 1961 as ''Project Y'' with a goal of “building a machine that was one hundred times faster than
Stretch”.
Initial work began at the
IBM Watson Research Center
The Thomas J. Watson Research Center is the headquarters for IBM Research. The center comprises three sites, with its main laboratory in Yorktown Heights, New York, U.S., 38 miles (61 km) north of New York City, Albany, New York and wi ...
. A number of significant computer pioneers contributed to the project, including
John Cocke,
Herb Schorr,
Frances Allen
Frances Elizabeth Allen (August 4, 1932August 4, 2020) was an American computer scientist and pioneer in the field of optimizing compilers. Allen was the first woman to become an IBM Fellow, and in 2006 became the first woman to win the Turing ...
,
Gene Amdahl, and
Lynn Conway
Lynn Ann Conway (born January 2, 1938) is an American computer scientist, electrical engineer and transgender activist.
She worked at IBM in the 1960s and invented generalized dynamic instruction handling, a key advance used in out-of-order ...
.
A decision by IBM in May 1968 to modify the project to support
S/360 compatibility resulted in the name change from ''ACS-1'' to ''ACS-360'' for the computer being designed. At its peak, the ACS-360 project involved over 200 engineers and staff.
The ACS-360 project was canceled in May 1969; however, many of the innovations resulting from the project would eventually find direct realization in the
IBM RS/6000 series of machines (later known as the
IBM System p
The IBM System p is a high-end line of RISC (Power)/ UNIX-based servers. It was the successor of the RS/6000 line, and predecessor of the IBM Power Systems server series.
History
The previous RS/6000 line was originally a line of workstation ...
line of workstations and servers), apart from influencing the design of other machines and architectures.
Influence
Although neither the ACS-1 nor the ACS-360 was ever manufactured, the IBM Advanced Computing Systems group responsible for their design developed architectural innovations and pioneered a number of
RISC
In computer engineering, a reduced instruction set computer (RISC) is a computer designed to simplify the individual instructions given to the computer to accomplish tasks. Compared to the instructions given to a complex instruction set comp ...
CPU design techniques that would become fundamental to the design of modern computer architectures and systems:
* Aggressive reduction in the number of logic gate levels for pipeline stages to reduce the cycle time
* Tight integration between processor and memory
* Cache memory with streamlined I/O to/from cache
* Compiler optimization techniques
* Virtual-memory operating systems
* Multiple instruction decode and issue (a first)
* Use of a branch target buffer (a first)
* Multithreading implemented in hardware (a first for IBM)
* Dynamic instruction scheduling/
out-of-order execution
In computer engineering, out-of-order execution (or more formally dynamic execution) is a paradigm used in most high-performance central processing units to make use of instruction cycles that would otherwise be wasted. In this paradigm, a proces ...
* Hardware
register renaming
In computer architecture, register renaming is a technique that abstracts logical registers from physical registers.
Every logical register has a set of physical registers associated with it.
When a machine language instruction refers to a partic ...
* Instruction predication
*
Level-sensitive scan design (used by IBM)
* Fixed-head hard disks
* Air-cooled high-speed LSI circuits
* Advanced simulation tools used in the design process
Notes
Further reading
*
External links
IBM Advanced Computing Systems (ACS) — 1961–1969— Documentation project for the IBM ACS-1 supercomputer maintained by Mark Smotherman
{{IBM
Advanced Computing Systems project
Advanced Computing Systems project