The Distributed Array Processor (DAP) produced by
International Computers Limited
International Computers Limited (ICL) was a British computer hardware, computer software and computer services company that operated from 1968 until 2002. It was formed through a merger of International Computers and Tabulators (ICT), English Ele ...
(ICL) was the world's first commercial
massively parallel computer. The original paper study was
complete in 1972 and building of the prototype began in 1974.
The first machine was delivered to
Queen Mary College
Queen Mary University of London (QMUL, or informally QM, and previously Queen Mary and Westfield College) is a public university, public research university in Mile End, East London, England. It is a member institution of the federal University of ...
in 1979.
Development
The initial 'Pilot DAP' was designed and implemented by Dr Stewart
F Reddaway with the aid of David J Hunt and Peter M Flanders at the
ICL Stevenage Labs. Their manager and a major contributor was
John K Iliffe who had designed the Basic Language Machine—he is well known nowadays for
Iliffe vector
In computer programming, an Iliffe vector, also known as a display, is a data structure used to implement multi-dimensional arrays. An Iliffe vector for an ''n''-dimensional array (where ''n'' ≥ 2) consists of a vector (or 1-dimension ...
s.
The ICL DAP had 64×64 single bit processing elements (PEs) with 4096 bits of storage per PE. It was attached to an ICL mainframe and its memory was mapped into the mainframe's memory. Programs for the DAP were written in
DAP FORTRAN which was
FORTRAN extended with 64×64 matrix and 64 element vector primitives. DAP Fortran compiled to an
assembly language
In computer programming, assembly language (or assembler language, or symbolic machine code), often referred to simply as Assembly and commonly abbreviated as ASM or asm, is any low-level programming language with a very strong correspondence be ...
called APAL (Array Processor Assembly Language). The DAP had a
Single Instruction Multiple Data (SIMD) architecture. Each operation could be performed under the control of a mask which controlled which elements were affected. Array programs were executed as subroutines of normal mainframe FORTRAN programs and IO was handled by the mainframe.
Operationally, there was an overhead to transfer computational data into and out of the array, and problems which did not fit the 64×64 matrix imposed additional complexity to handle the boundaries (65×65 was perhaps the worst case!)—but for problems which suited the architecture, it could outperform the current
Cray
Cray Inc., a subsidiary of Hewlett Packard Enterprise, is an American supercomputer manufacturer headquartered in Seattle, Washington. It also manufactures systems for data storage and analytics. Several Cray supercomputer systems are listed ...
pipeline architectures by two orders of magnitude. The
ICL 2980 was not a popular machine and this held back the use of the DAP as an attached processor was restricted initially to this one range.
The design as described in Reddaway's 1973 paper is pretty much that which was implemented in the first commercial version except the facility to supply address bits from the processing elements was removed. This change greatly simplified hardware error detection. A notable extra facility was carry propagation to simplify vector mode addition.
After ICL
The DAP
Pwas sold off to a
venture capital
Venture capital (often abbreviated as VC) is a form of private equity financing that is provided by venture capital firms or funds to startups, early-stage, and emerging companies that have been deemed to have high growth potential or which ha ...
-funded
start-up company
Active Memory Technology
(AMT) which was then taken over by
Cambridge Parallel Processors (CPP).
It was enhanced and made smaller and faster as the Gamma series.
An 8-bit processor with some local 8-bit wide memory was added to the
processor and fast IO capabilities were implemented. It could be programmed in either
C++
C++ (pronounced "C plus plus") is a high-level general-purpose programming language created by Danish computer scientist Bjarne Stroustrup as an extension of the C programming language, or "C with Classes". The language has expanded significan ...
or
Fortran-Plus. These were more flexible than DAP FORTRAN, in particular they automatically took care of choosing a mapping from user specified matrix and vector bounds to the underlying hardware.
Sample DAPs are in storage at the
Computer History Museum
The Computer History Museum (CHM) is a museum of computer history, located in Mountain View, California. The museum presents stories and artifacts of Silicon Valley and the information age, and explores the computing revolution and its impact on ...
.
CPP ceased trading in 2004.
Mini-DAP and Mil-DAP
A smaller 32x32 version was created between 1984 and 1987. The commercial version was called the Mini-DAP, normally attached to a
PERQ
The PERQ, also referred to as the Three Rivers PERQ or ICL PERQ, was a pioneering workstation computer produced in the late 1970s through the early 1980s. In June 1979, the company took its very first order from the UK's Rutherford Appleton La ...
system (so was sometimes called the PERQ-DAP), and the ruggedised military version was called the Mil-DAP.
See also
*
Goodyear MPP
The Goodyear Massively Parallel Processor (MPP) was a
massively parallel processing supercomputer built by Goodyear Aerospace
for the NASA Goddard Space Flight Center. It was designed to deliver enormous computational power at lower cost than oth ...
*
Thinking Machines
Thinking Machines Corporation was a supercomputer manufacturer and artificial intelligence (AI) company, founded in Waltham, Massachusetts, in 1983 by Sheryl Handler and W. Daniel "Danny" Hillis to turn Hillis's doctoral work at the Massachuset ...
Connection Machine
A Connection Machine (CM) is a member of a series of massively parallel supercomputers that grew out of doctoral research on alternatives to the traditional von Neumann architecture of computers by Danny Hillis at Massachusetts Institute of Techno ...
*
MasPar
MasPar Computer Corporation was a minisupercomputer vendor that was founded in 1987 by Jeff Kalb. The company was based in Sunnyvale, California.
History
While Kalb was the vice-president of the division of Digital Equipment Corporation (DEC) t ...
*
Parsytec
*
SUPRENUM
SUPRENUM (german: SUPerREchner für NUMerische Anwendungen, en, super-computer for numerical applications) was a German research project to develop a parallel computer from 1985 through 1990. It was a major effort which was aimed at developing a n ...
References
External links
*
DAP personal history
{{DEFAULTSORT:Icl Distributed Array Processor
DAP
DAP or Dap may refer to:
Science
* DAP (gene), human gene that encodes death-associated proteins, which mediate programmed cell death
* Diamidophosphate, phosphorylating compound
* Diaminopimelic acid, amino acid derivative of lysine
* Diamin ...
Massively parallel computers
DAP
DAP or Dap may refer to:
Science
* DAP (gene), human gene that encodes death-associated proteins, which mediate programmed cell death
* Diamidophosphate, phosphorylating compound
* Diaminopimelic acid, amino acid derivative of lysine
* Diamin ...