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The Evolution of Minicomputers: From Transistors to Microprocessors



A computer class contains several groups with its software architectures and operating systems. The minicomputer was developed for computing tasks such as calculation, store records, controls, human interactions, etc.




minicomputer



The minicomputer came into existence in the mid of 1960s. At that time, It was the only small computer that uses transistors and core memory technologies. The first minicomputer was known as Digital Equipment Corporation. It cost approximately 16000 USD.


[David Lovett] aka Usagi Electric has spent the last several months dissecting a Centurion minicomputer from 1980. His latest update reveals that the restoration has hit several snags, and bootstrapping this old blue beast is going to be a challenge.


But his own company fell victim to disruption itself as it failed to deal with the personal computer revolution, which undercut the minicomputer industry. Still, he will be remembered as a pioneer of the computer industry and as the leader of DEC, which he ran for 35 years. His company was one of the first tech firms to get venture capital.


The main routine statistical analyses can be carried out from start to finish on a minicomputer with basic language capability and greater than or equal to 32000 bytes of random access memory. However, no statistical software packs for minicomputers are ever complete enough for exhaustive analysis of most problems. Taking account of the requirements of statistical models, this paper gives an outline of how to set up a program. Examples are given from the package of statistical programs developed at this institute. The advantages and disadvantages of making these analyses on minicomputers are discussed, in comparison with the use of statistical programs requiring large computers.


(2) An earlier medium-scale, centralized computer that functioned as a multiuser system for up to several hundred users. The minicomputer industry was launched in 1959 after Digital Equipment Corporation introduced its PDP-1 for $120,000, an unheard-of low price for a computer in those days. Subsequently, a variety of minicomputer systems became available from HP, Data General, Wang, Tandem, Datapoint, Prime Computer, Varian Data and Scientific Data Systems. The single user mini evolved into a centralized system with dumb terminals for departmental use.


During the 1980s and early 1990s, most centralized minicomputers migrated from their dumb terminal architecture into servers for PC networks. The terms "midrange computer" and "server" replaced the venerable minicomputer designation.


Some applications of the minicomputer were data acquisition, process control, time-sharing, and terminal and peripheral communication control. Process control systems involve data acquisition and feedback to control the process, with or without human intervention. The machine-machine system involves the use of a minicomputer as a front end communications processor or a peripheral control unit. This offloads the tasks of error checking, polling, hand-shaking, line buffering, or other formatting from the large central processor. Minicomputers were also used in stand-alone or single-user mode to do human research such as reaction time studies. The stand-alone mode was necessary to provide timing independent of other processes.


The minicomputer was capable of performing under normal environmental conditions and did not require the extensive power and air-conditioning of larger but more delicate systems. It could also be made rugged ("rugged-ized") to perform in adverse environments such as combat fronts. It was a more durable tool than many larger systems and more easily transportable. It could also be used in factories for process control, inventory and manufacturing control, or as a satellite to a larger computer, feeding data to it or acting as a peripheral device.


The growth of the minicomputer market was relatively rapid. It began in the 1960s and expanded in the early 1970s. The key to its growth was the development of large-scale integrated circuitry (LSI). Integrated circuits (ICs) were developed in the 1960s, initially with a single function on a chip, a logic gate or flip-flop (memory element); then with medium-scale integration (MSI), with a dozen or more functions on a chip; and, finally, large-scale integration (LSI), with more than 100 functions on a chip; and later, with very large-scale integration (VLSI). The availability of large-scale integration lowered the costs of developing a computer and also aided in the replicability of the manufacturing process. This enabled batch processing , as well as modular construction and the interchangeability of parts.


The minicomputer system was designed to balance the needs of input/output and storage with the computing needs in a cost-effective way. The software for a mini usually consisted of an assembler, editor, several compilers , and utility programs. The operating systems were of various types, including paging systems. Some minicomputers were application-specific; the hardware and peripherals, as well as the software, or driver program, were tailored to the application. This was especially true of military, airborne, or other special uses of the computer. Minicomputers were used in some of the early American space launches.


Some of the compilers available with minicomputers were FORTRAN (FORmula TRANslator) IV, Algol, RPG, Basic (interpreter), and, eventually, C and Unix. C and the associated operating system Unix, and much of the early work at Bell Laboratories on computers and computer software, were done on the PDP-series computers (Digital Equipment's PDP-x family). Other manufacturers were Data General, Varian, Hewlett-Packard, Honeywell, and Texas Instruments.


Disk operating systems were developed for minicomputers because the amount of main memory was limited. If the operating system took up between 12 kilobytes (K) and 20K of memory and only 32K was available, a limited amount was left for user programs. The operating system was divided into resident and non-resident portions, and the non-resident portions of the operating system as well as user programs were rolled, or swapped, in and out as necessary. One machine of the PDP series implemented time-sharing by swapping whole programs in and out of main memory, with one user program resident at a time.


The minicomputer led to an unexpected development. The PDPseries of computer was expanded in 1975 to the Virtual Address eXtension (VAX) series of computers. The VAX was a 32-bit machine that was comparable to a mainframe, though not in terms of the large cost of some of the mainframes of the day (several million dollars). As of the year 2002, the VAXseries of computers was still in use in universities and elsewhere. It is a phenomenon in the fast-moving computer market.


From the 1965 perspective of a mainframe computer company, minicomputers were not even competition. Minicomputers were never encountered in selling situations, and mainframes rented for $20,000 a month. The PDP-8 cost $18,000. But advances in semiconductor technologies, Medium Scale Integration (MSI) to Large Scale Integration (LSI) to Very Scale Integration (VLSI)200 , and software and peripherals, such as Winchester Disk Drives, all allowed more computing resources to be sold as the DEC VAX-11/780 minicomputer in 1979 than existed in the IBM System/360 mainframe in 1965. And by 1988, personal computers represented an alternative to both mainframes and minicomputers.201


Human Resources - In just four years, the number of minicomputer firms exceeded the number of Second Generation mainframe computers ninety-two to sixteen. Many firms could not have existed without a tremendous diffusion of knowledge and training of personnel.


The oligopoly in minicomputers consisted of four firms, or five percent of all entrants. (DEC, IBM, DG and Prime) Over sixty percent of entrants were start-ups. As of 1983, 53% of all entrants had failed and no longer existed.


In 1976, DEC, once again played catch up, only this time it was to ship a 32-bit computer. Despite holding a 40% market share, DEC now lagged Prime Computer, the first to introduce a commercially successful 32-bit minicomputer, by four years. And everyone believed, correctly, that future growth in minicomputers would be in 32-bit architectures, just as it once had been in 8-bit and 16-bit architectures.


A minicomputer is a small general-purpose computer that uses one or more processors to complete work. With limited expandability of processing power, RAM storage, they fall between microcomputers and mainframe computers.


The main purpose of minicomputers is to allow individuals to do computing efficiently without needing to access a mainframe. Minicomputers can also be used control manufacturing processes and process business transactions. Further, they are used to control scientific and laboratory experiments and process the data generated by those experiments.


The minicomputer operates the same way as a mainframe computer does. The CPU of a minicomputer contains integrated semiconductor chips that perform all arithmetic and logic functions. This processor handles intensive computing tasks or high workloads locally while connecting to a server.


Seemingly a contradiction in terms, a midsized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from 4 to about 200 users simultaneously. 2ff7e9595c


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