Burroughs was one of the nine major United States computer companies in the 1960s, with
IBM the largest,
Honeywell,
NCR Corporation,
Control Data Corporation (CDC),
General Electric (GE),
Digital Equipment Corporation (DEC),
RCA and
Sperry Rand (
UNIVAC line). In terms of sales, Burroughs was always a distant second to
IBM. In fact, IBM's market share was so much larger than all of the others that this group was often referred to as "IBM and the Seven Dwarves." By 1972 when GE and RCA were no longer in the mainframe business, the remaining five companies behind IBM became known as the
BUNCH, an
acronym based on their initials. At the same time, Burroughs was very much a competitor. Like IBM, Burroughs tried to supply a complete line of products for its customers, including Burroughs-designed printers,
disk drives,
tape drives, computer printing paper and
typewriter ribbons.
Developments and innovations The Burroughs Corporation developed three highly innovative
architectures, based on the design philosophy of "
language-directed design". Their machine instruction sets favored one or many
high level programming languages, such as
ALGOL,
COBOL or
FORTRAN. All three architectures were considered
mainframe class machines: • The
Burroughs Large Systems machines started with the B5000 in 1961. The B5500 came a few years later when large rotating disks replaced drums as the main external memory media. These B5000 Series systems used the world's first virtual memory multi-programming operating system. They were followed by the B6500/B6700 in the later 1960s, the B7700 in the mid-1970s, and the A series in the 1980s. The underlying architecture of these machines is similar and continues today as the
Unisys ClearPath MCP line of computers:
stack machines designed to be programmed in an extended
Algol 60. Their
operating systems, called MCP (
Master Control Program—the name later borrowed by the screenwriters for
Tron), were programmed in
ESPOL (Executive Systems Programming Oriented Language, a minor extension of ALGOL) and DCALGOL (Data Communications ALGOL) and later in NEWP (with further extensions to ALGOL) almost a decade before
Unix. The command interface developed into a compiled
structured language with declarations, statements and procedures called WFL (
Work Flow Language). Many
computer scientists consider these series of computers to be technologically groundbreaking. Stack-oriented processors with 48-bit word length where each word was defined as data or program contributed significantly to a secure operating environment, long before
spyware and
viruses affected computing. The modularity of these large systems was unique: multiple
CPUs, multiple memory modules and multiple
I/O and Data Comm processors permitted incremental and
cost effective growth of system performance and reliability. In industries like banking, where continuous operations was mandatory, Burroughs Large Systems penetrated nearly every large bank, including the
Federal Reserve Bank. Burroughs built the backbone
switching systems for
Society for Worldwide Interbank Financial Telecommunication (SWIFT) which sent its first message in 1977. Unisys is still the provider to SWIFT today. • Burroughs produced the
B2500 or "medium systems" computers aimed primarily at the business world. The machines were designed to execute
COBOL efficiently. This included a BCD (
binary-coded decimal) based arithmetic unit, storing and addressing the main memory using
base 10 numbering instead of
binary. The designation for these systems was Burroughs B2500 through B49xx, followed by Unisys V-Series V340 through V560. • Burroughs produced the
B1700 or "small systems" computers that were designed to be
microprogrammed, with each process potentially getting its own
virtual machine designed to be the best match to the
programming language chosen for the program being run. • The smallest general-purpose computers were the B700 "microprocessors" which were used both as stand-alone systems and as special-purpose data-communications or disk-subsystem controllers. • Burroughs manufactured an extensive range of
accounting machines including stand-alone systems such as the
Sensimatic, L5000 and B80 and dedicated terminals including the TC500 and specialised check processing equipment. • In 1982, Burroughs began producing
personal computers, the
B20 and B25 lines with the
Intel 8086/
8088 family of 16-bit chips as the processor. These ran the
BTOS operating system, which Burroughs licensed from
Convergent Technologies. These machines implemented an early
local area network to share a
hard disk between
workgroup users. These microcomputers were later manufactured in
Kunming,
China for use in China under agreement with Burroughs. • Burroughs collaborated with
University of Illinois on a multiprocessor architecture developing the
ILLIAC IV computer in the early 1960s. The ILLIAC had up to 128 parallel processors while the B6700 & B7700 only accommodated a total of 7 CPUs and/or I/O units (the 8th unit was the memory tester). • Burroughs made military computers, such as the D825 (the "D" prefix signifying it was for defense industrial use), in its Great Valley Laboratory in
Paoli, Pennsylvania. The D825 was, according to some scholars, the first true multiprocessor computer. Paoli was also home to the Defense and Space Group Marketing Division. • In 1964 Burroughs had completed the D830 which was another variation of the D825 designed specifically for real-time applications, such as airline reservations. Burroughs designated the B8300 after
Trans World Airlines (TWA) ordered one in September 1965. A system with three instruction processors was installed at TWA's reservations center in
Rockleigh, New Jersey in 1968. The system, which was called George, with an application programmed in
JOVIAL, was intended to support some 4000 terminals, but the system experienced repeated crashes due to a filing system disk allocation error when operating under a large load. A fourth processor was added but did nothing to resolve the problem. The problem was resolved in late 1970 and the system became stable. The decision to cancel the project was being made at the very time that the problem was resolved. TWA cancelled the project and acquired one
IBM System/360 Model 75, two IBM System/360 model 65s, and IBM's
PARS software for its reservations system. TWA sued Burroughs for non-fulfillment of the contract, but Burroughs counter-sued, stating that the basic system did work and that the problems were in TWA's applications software. The two companies reached an out-of-court settlement. • Burroughs developed a half-size version of the D825 called the D82, cutting the word size from 48 to 24 bits and simplifying the computer's instruction set. The D82 could have up to 32,768 words of core memory and continued the use of separate instruction and I/O processors. Burroughs sold a D82 to
Air Canada to handle reservations for trips originating in
Montreal and
Quebec. This design was further refined and made much more compact as the
D84 machine which was completed in 1965. A D84 processor/memory unit with 4096 words of memory occupied just . This system was used successfully in two military projects: field test systems used to check the electronics of the Air Force
General Dynamics F-111 Aardvark fighter plane and systems used to control the countdown and launch of the Army's
Pershing 1 and
1a missile systems. ==Merger with Sperry==