From Mainframe to Minicomputer, 19591969

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From Mainframe to Minicomputer, 1959-1969

• Introduction
• Influence of the Federal Government
• Massachusetts Blue Cross
• NASA-Ames Research Center
• IRS
• NASAs Manned Space Program
• The Minicomputer
• Architecture
• The Digital Equipment Corporation
• The PDP-8
• The DEC Culture
• The MIT Connection

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Introduction

• The era of Mainframe computer
• From Mainframe to Minicomputer
• The Minicomputer
• IBM
• DEC Digital Equipment Corporation
• PDP-8
• IBM market share of 70
• System/360 System/370

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The Influence of the Federal Government

• US Defense Department funded major computing
  projects.
• DoD impact on the advancement of computing
  technology
• Massachusetts Blue Cross
• In 1960 Blue Cross acquired the IBM 7070 to
  process work that was previously done on
  tabulating machines
• Blue Cross uses the IBM 1401 data input and
  output only
• Blue Cross uses AUTOCODER instead of COBOL or
  FORTRAN in order to save memory and for faster
  compilation process
• In 1967 Blue Cross acquired IBMs System/360

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The Influence of the Federal Government

• NASA Ames Research Center
• In 1955 Ames acquired its first stored-program
  electronic computer IBM 650
• In 1958 Ames became part of the National
  Aeronautic Space Administration (NASA)
• NASA acquired IBM 704, and replaced it with IBM
  7090 - used for scientific calculations
• NASA acquired systems from various vendors the
  H-800 from Honeywell, and other machines for
  dedicated purposes (operating a flight simulator)
• Vendors were Honeywell, DEC, Scientific Data
  Systems, EAI, and IBM
• In 1963, the 7090 system was upgraded to a
  complex of machines called a Direct Couple System
• The purpose of this machine was to do scientific
  work

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The Influence of the Federal Government

• NASA Ames Research Center
• The 7094 was the main machine coupled with the
  7040 to handle I/O
• Each of these machine had a core memory of 32,768
  36-bit words
• IBM 7740 communication computer connected to
  several remote terminals
• Within the Direct Coupled System was the IBM 1401
  that handle printing results, and could operate
  as a stand alone computer
• The Direct Couple System cost about 1.6mil, and
  work well for NASA and was replaced by System/360
  model 50 at a rental fees of 21,000 a month for
  processor and 45,000 for entire system a month

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IRS

• IRS Internal Revenue Service
• The IRS
• In 1959 the US Treasury Department authorized the
  IRS to computerize its operation
• IRS selected IBM to provide its computing system
• IBM 1401 was installed in each of IRS regional
  center
• The 1401has a capacity of 4K core memory, a card
  reader, punch, line printer, and two tape drives

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NASA Manned Space Program

• NASA
• NASA use of computers to facilitate its space
  program
• Minicomputer
• From vacuum tubes to transistors to integrated
  circuits.
• Minicomputer comes out of demands from well
  funded customers
• Minicomputer was never a direct competitor to
  mainframe, rather it was for new application, and
  to satisfy new demand in cultural, economic, and
  technological progress
• Architecture

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Architecture

• Architecture
• The architecture of computer (minicomputer)
  varies in-term of packaging, third parties parts
  and applications, price, etc.
• IBM mainframe in the early 1960s operated on a
  36bits at a time using one or more registers in
  its central processors
• The fastest, most complex, and expensive
  circuits were built into this part of the computer

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Architecture

• Architecture
• Mode operation could refer to a register in which
  the desired memory location is stored
• Complexity?
• Double-precision?
• Improved and available new transistor in the late
  1950s result into a processor design that was
  simple, inexpensive, and fast system
• Commercial minicomputers begins with an inventor
  associated with large computers
• Seymour Cray Supercomputer
• In 1957 CDC was founded by William Norris

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Architecture

• Architecture
• A shorter word length computer lower the
  complexity and cost of the computer
• Shorter word length also meant less bits in an
  instruction to specify enough memory addresses
• IBM 7090 series with a 36-bit word gave the
  equivalent of ten decimal digits
• Minicomputers fixed this problem by making the
  computers instruction codes more complex
• Minicomputer used several bits of the code to
  specify different modes to extend memory space

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Architecture

• Architecture
• In 1960 CDC introduced its 1604 model computer
  intended for scientific customers
• Cray designed the 160 model to handle input and
  output for the 1604
• The 160 used short word length (12 bits) using
  ways of accessing memory beyond the limits of a
  short address field
• 160 directly address primary memory of eight
  thousand words, a fast clock (6.4microsecond) for
  memory access
• 160 was inexpensive to produce
• 160A a standalone version (60k)

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Architecture

• Architecture
• The 160A help to open the market of computers
  that were not tied to the mainframe architecture
  and size
• Jack Scantlin of Scantlin Electronic, Inc. In
  1962 - was one of the first to build a system
  like the 160A to provide on-line quotations from
  the NYSE to brokers across the country
• By 1963 SEIs Quotron II provide stock prices
  within 15 seconds

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The Digital Equipment Corp

• DEC
• In 1957 Kenneth Olsen and Harlan Anderson
  founded the DEC
• In 1955 Olson took charge of the TX-0 computer in
  the Lincoln Lab
• TX-0 first operated at Lincoln Lab in 1956
• TX-0 completed in 1957 was one of the most
  advanced computer in the world
• DEC PDP-1 designed by Gurley uses TX-0
  architecture and circuit innovations
• Although PDP-1 uses the TX-0 architectural
  features they were not exact copy each other

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The Digital Equipment Corp

• DEC
• PDP-1 I/O proceed directly from an I/O device to
  the core memory itself which makes the I/O
  faster with minimal operation on the central
  processor
• DMA Direct Memory Access was incorporated in
  nearly all DEC products and defined the
  architecture of the minicomputer
• DMA was built into the microprocessors used in
  modern computers
• DMA process allowed interrupts to occur at
  multiple levels (16) with circuits dedicated to
  handling them in the right order

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The Digital Equipment Corp

• DEC
• PDP-1 was sold to customers. It was not leased.
  Customers were encouraged to modified the PDP-1
• Initial selling price was 120,000
• It was described to cheaper than the IBM channel
  on its mainframe computer
• DEC educated its customers about its products
• DEC PDP-8
• PDP-8 show the market size. DEC installed over
  50,000 PDP-8 systems
• PDP-8 had a word length of 12 bits

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The Digital Equipment Corp

• DEC PDP-8
• Influences on PDP-8 from CDC-160, and LINC by Wes
  Clark 12 bit word length
• The success of PDP-8, and the minicomputer was
  due to a convergence including performance,
  storage, packaging, and price
• PDP-8s circuits used germanium transistors made
  by micro-alloy diffused process, pioneered by
  Philco.
• PDP-8 perform about 35,000 additions per second
• PDP-8 had 4 thousand words of memory, divided
  into 32 blocks of 128 words each

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Conclusion