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The JOHNNIAC was an early computer built by the RAND Corporation (not Remington Rand, maker of the contemporaneous UNIVAC I computer) and based on the von Neumann architecture that had been pioneered on the IAS machine. It was named in honor of von Neumann, short for John von Neumann Numerical Integrator and Automatic Computer. [1]
After being rescued from the scrap heap twice, the machine is currently at the Computer History Museum in Mountain View, California. [2]
Like the IAS machine, JOHNNIAC used 40-bit words, and included 1024 words of Selectron tube main memory, each holding 256 bits of data. Two instructions were stored in every word in 20-bit subwords consisting of an 8-bit instruction and a 12-bit address, the instructions being operated in series with the left subword running first. The initial machine had 83 instructions. A single register, named A, supplied an accumulator and the machine also featured a register named Q, for quotient. There was only one test condition, whether or not the high bit of the A register was set. There were no index registers, and as addresses were stored in the instructions, loops had to be implemented by modifying the instructions as the program ran. Since the machine only had 10 bits of address space, two of the address bits were unused and were sometimes used for data storage by interleaving data through the instructions.
JOHNNIAC weighed 5,000 pounds (2.5 short tons; 2.3 t). [3]
Numerous modifications were made to the system over its lifetime. In March 1955, 4096 words of magnetic-core memory were added to the system, replacing the earlier Selectrons. This required all 12 bits of addressing, and caused programs that stored data in the "spare bits" to fail. Later in 1955 a 12k-word drum memory secondary storage system was added as well. A transistor-based adder replaced the original tube-based adder in 1956. Numerous changes were made to the input/output peripherals as well, and in 1964, a real-time clock was added to support time-sharing.
One JOHNNIAC legacy was the JOSS programming language (the JOHNNIAC Open Shop System), an easy-to-use language which catered to novices. JOSS was an ancestor of DEC's FOCAL and of MUMPS.
The CYCLONE at Iowa State University was a direct clone of JOHNNIAC, and was instruction compatible with it; the ILLIAC I at the University of Illinois may have been as well. Cyclone was later updated to include hardware for floating-point arithmetic.
A central processing unit (CPU)—also called a central processor or main processor—is the most important processor in a given computer. Its electronic circuitry executes instructions of a computer program, such as arithmetic, logic, controlling, and input/output (I/O) operations. This role contrasts with that of external components, such as main memory and I/O circuitry, and specialized coprocessors such as graphics processing units (GPUs).
Computer data storage is a technology consisting of computer components and recording media that are used to retain digital data. It is a core function and fundamental component of computers.
The Harvard architecture is a computer architecture with separate storage and signal pathways for instructions and data. It is often contrasted with the von Neumann architecture, where program instructions and data share the same memory and pathways.
EDVAC was one of the earliest electronic computers. It was built by Moore School of Electrical Engineering, Pennsylvania. Along with ORDVAC, it was a successor to the ENIAC. Unlike ENIAC, it was binary rather than decimal, and was designed to be a stored-program computer.
JOSS was one of the first interactive, time-sharing programming languages. It pioneered many features that would become common in languages from the 1960s into the 1980s, including use of line numbers as both editing instructions and targets for branches, statements predicated by boolean decisions, and a built-in source-code editor that can perform instructions in direct or immediate mode, what they termed a conversational user interface.
The IBM 650 Magnetic Drum Data-Processing Machine is an early digital computer produced by IBM in the mid-1950s. It was the first mass produced computer in the world. Almost 2,000 systems were produced, the last in 1962, and it was the first computer to make a meaningful profit. The first one was installed in late 1954 and it was the most-popular computer of the 1950s.
The IBM 701 Electronic Data Processing Machine, known as the Defense Calculator while in development, was IBM’s first commercial scientific computer and its first series production mainframe computer, which was announced to the public on May 21, 1952. It was invented and developed by Jerrier Haddad and Nathaniel Rochester based on the IAS machine at Princeton.
The IAS machine was the first electronic computer built at the Institute for Advanced Study (IAS) in Princeton, New Jersey. It is sometimes called the von Neumann machine, since the paper describing its design was edited by John von Neumann, a mathematics professor at both Princeton University and IAS. The computer was built under his direction, starting in 1946 and finished in 1951. The general organization is called von Neumann architecture, even though it was both conceived and implemented by others. The computer is in the collection of the Smithsonian National Museum of American History but is not currently on display.
The Cyclone is a vacuum-tube computer, built by Iowa State College at Ames, Iowa. The computer was commissioned in July 1959. It was based on the IAS architecture developed by John von Neumann. The Cyclone was based on ILLIAC, the University of Illinois Automatic Computer. The Cyclone used 40-bit words, used two 20-bit instructions per word, and each instruction had an eight-bit op-code and a 12-bit operand or address field. In general IAS-based computers were not code compatible with each other, although originally math routines which ran on the ILLIAC would also run on the Cyclone.
The ILLIAC IV was the first massively parallel computer. It is part of the ILLIAC series of computers. The system was originally designed to have 256 64-bit floating point units (FPUs) and four central processing units (CPUs) able to process 1 billion operations per second. Due to budget constraints, only a single "quadrant" with 64 FPUs and a single CPU was built. Since the FPUs all had to process the same instruction – ADD
, SUB
etc. – in modern terminology the design would be considered to be single instruction, multiple data, or SIMD.
The UNIVAC 1100/2200 series is a series of compatible 36-bit computer systems, beginning with the UNIVAC 1107 in 1962, initially made by Sperry Rand. The series continues to be supported today by Unisys Corporation as the ClearPath Dorado Series. The solid-state 1107 model number was in the same sequence as the earlier vacuum-tube computers, but the early computers were not compatible with the solid-state successors.
The IBM 700/7000 series is a series of large-scale (mainframe) computer systems that were made by IBM through the 1950s and early 1960s. The series includes several different, incompatible processor architectures. The 700s use vacuum-tube logic and were made obsolete by the introduction of the transistorized 7000s. The 7000s, in turn, were eventually replaced with System/360, which was announced in 1964. However the 360/65, the first 360 powerful enough to replace 7000s, did not become available until November 1965. Early problems with OS/360 and the high cost of converting software kept many 7000s in service for years afterward.
The Selectron was an early form of digital computer memory developed by Jan A. Rajchman and his group at the Radio Corporation of America (RCA) under the direction of Vladimir K. Zworykin. It was a vacuum tube that stored digital data as electrostatic charges using technology similar to the Williams tube storage device. The team was never able to produce a commercially viable form of Selectron before magnetic-core memory became almost universal.
The von Neumann architecture—also known as the von Neumann model or Princeton architecture—is a computer architecture based on a 1945 description by John von Neumann, and by others, in the First Draft of a Report on the EDVAC. The document describes a design architecture for an electronic digital computer with these components:
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The Manchester Baby, also called the Small-Scale Experimental Machine (SSEM), was the first electronic stored-program computer. It was built at the University of Manchester by Frederic C. Williams, Tom Kilburn, and Geoff Tootill, and ran its first program on 21 June 1948.
In computing, a memory address is a reference to a specific memory location used at various levels by software and hardware. Memory addresses are fixed-length sequences of digits conventionally displayed and manipulated as unsigned integers. Such numerical semantic bases itself upon features of CPU, as well upon use of the memory like an array endorsed by various programming languages.
ILLIAC was a series of supercomputers built at a variety of locations, some at the University of Illinois at Urbana–Champaign. In all, five computers were built in this series between 1951 and 1974. Some more modern projects also use the name.
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George William Brown was an American statistician, game theorist, and computer scientist known for his work and research in early computing machinery, game theory, mathematical logic, decision theory and administration. He was a major force in the design and construction of early computing machinery, including the IAS machine, and subsequently directed the construction of JOHNNIAC. His publication of EDUNET in 1967 presaged the details and rise of the early internet. The concept of fictitious play in game theory is due to him.