Microcomputer
A microcomputer, microcomputer, or microcomputer is a small computer, with a microprocessor as its central processing unit CPU., the microprocessor includes the storage (or cache) and input/output circuitry on the same integrated circuit (or chip). Microcomputers became popular in the 1970s and 1980s with the advent of more powerful microprocessors. The predecessors of these computers, supercomputers and minicomputers, were much larger and more expensive (although modern supercomputers, such as the IBM System z, use one or more microprocessors as CPUs). Many microcomputers (when equipped with a keyboard and display for input and output) are also personal computers (in a general sense). The abbreviation micro was commonly used during the 1970s and 1980s, although it is now deprecated.
Origins
The term microcomputer became popular after the introduction of the term minicomputers, although Isaac Asimov had already used it in his short story "The Dying Night" in 1956 (published in The Magazine of Fantasy and Science Fiction in July of that year). Notably, the microcomputer replaced the various components that made up the minicomputer's CPU with a single integrated microprocessor.
The first microcomputer was the Japanese SMP80/08 from Sord Computer Corporation (1972), which was followed by the SMP80/x (1974). The French developers of the Micral N (1973) filed their patents under the term &# 34;Micro-ordinateur", literally equivalent to "Microcomputer" (microcomputer), to name the first solid-state machine with a microprocessor.
In the United States, early models such as the Altair 8800, were often sold as a user-assembled package, and came with 256-byte RAM; and as the only input and output devices, the light indicators and switches, demonstrating as a proof of concept, how simple a device could be.
As microprocessors and semiconductor memories became less expensive, microcomputers became cheaper and easier to use:
- The increase of less expensive logical chips such as the 7400 series allowed to use cheaper dedicated circuits to improve user interfaces such as the keyboard, instead of switches to process a bit at a time.
- The use of audio cassettes to store data allowed the replacement of manual re-entry of the programs whenever the devices were lit.
- The silicon logical door arrays in the form of read-only memories and EPROMs enabled the storage of useful software and auto-boot kernels in the microcomputers. These storage programs could automatically load more complex software from external storage devices, without user intervention to form a fully ready system that did not require expert computer knowledge to use the device.
- Random access memories were reduced enough to offer approximately 1-2 kilobytes of memory dedicated to the buffers of the video control device, 40x25 or 80x25 to display texts or blocks of graphic colors on a current television screen. This replaced the expensive, complex and expensive teleprinter, which was commonly used as the interface of the minicomputers and supercomputers.
All of these improvements in cost and usability resulted in an explosion of popularity in the late 1970s and early 1980s. A large number of computer manufacturers packaged microcomputers for use in small business applications. By 1979, many companies, such as Cromemco, Processor Technology, IMSAI, North Star Computers, Southwest Technical Products Corporation, Ohio Scientific, Altos Computer Systems, Morrow Designs, and others, produced systems such as database, accounting, and word processing systems., designed both for users with all resources or consulting firms, as well as for specific business systems. This allowed businesses unable to license minicomputers or share service time the opportunity to automate their functions, without hiring full-time staff to operate the computers. A representative of these systems used an S-100 bus, an 8-bit processor such as Intel 8080 or Zilog Z80, and CP/M or MP/M operating system.
The 1980s saw the boom of the 8-bit home computer (and game consoles) with a multitude of competitors (Sinclair Research, Amstrad, Commodore International, Atari, Dragon Data, Texas Instruments, Tandy, the manufacturers of MSX...) but the move to 16 bits leaves only the Atari ST, Commodore Amiga, Macintosh and IBM PC compatible as contenders for the personal computer market. Space cases are Tandy computers compatible with the IBM PCjr and the Sinclair QL.
The jump to 32 bits will bring the fall of Atari, Commodore and Tandy (despite presenting powerful equipment), leaving the market divided between the minority but always innovative Mac (saved by the hairs with the return of Steve Jobs) and the huge market for the IBM PC compatible, which has been imposed on the market by the use of standard components and which the consortium of manufacturers discovers that it is more productive to define new standards that everyone adopts than to reinvent the wheel, main cause of the collapse of Atari and Commodore. The latest episode on this path was Apple's adoption of Intel processors for its Macs and allowing dual-booting of its Mac OS/Windows computers.
In fact, the term IBM PC compatible has become meaningless since IBM left the market with the failure of its IBM Personal System/2 range (which nevertheless provides two standards to the current PC), the Most IBM PC ports and drivers are considered legacy by the industry, which rarely implements them on its new computers and Microsoft Windows has replaced DOS and OS/2
Modern desktop and laptop computers, game consoles, tablets, and many other types of devices, including smartphones, and embedded industrial systems, can all be considered examples of microcomputers according to the definitions given.
Colloquial use of the term
Every day the use of the expression "microcomputer" (and particularly the abbreviation "micro") has fallen further out of use since the mid-1980s, and as of 2000 is no longer considered a common term. This term is commonly associated with the first wave of 8-bit home and small business computers (such as the Apple II, Commodore 64, BBC Micro, and TRS 80). In addition, perhaps the wide variety of modern microprocessor-based devices that fit the definition of "microcomputers" play a role.
In common usage, "microcomputer" has been supplanted by "personal computer" or "PC," which describes computers that have been created to be used by one person at a time, a term coined in 1959. IBM was the first to promote the term "personal computer" to differentiate themselves from other microcomputers, often called 'home computers', in addition to IBM's own supercomputers and minicomputers. However, after its release, the IBM PC by IBM was widely imitated, as was the term microcomputer. The components were commonly available to manufacturers and the BIOS was reserved for engineers. The "clones" of IBM PCs became popular, and the terms "personal computer," and especially "PC" used by the general public.
Since the advent of microcontrollers (monolithic integrated circuits containing RAM, ROM, and CPU all on the same board), the term "micro" is more commonly used to refer to that meaning.
Description
Monitors, keyboards, and other input and output devices can be integrated or separate. Computer memory in the form of RAM, and at least one other less volatile memory storage device, is often combined with the CPU on a system bus in a drive. Other devices that make up a complete microcomputer system include batteries, a power supply, a keyboard, and various input/output devices that are used to transmit information to and from a human operator (printers, monitors, human interface devices). Microcomputers are designed to serve a single user at a time, although they can often be modified by software or hardware to serve more than one user at a time. Microcomputers fit well inside or under desks or tables so that they are easily accessible by users. Larger computers like minicomputers, mainframes, and supercomputers occupy large cabinets or even dedicated rooms.
A microcomputer comes equipped with at least one type of data storage, usually RAM. Although some microcomputers (particularly early 8-bit microcomputers) perform tasks using only RAM, some form of secondary storage is preferable. In early computers this was often a data cassette player (in many cases as an external drive). Later, secondary storage systems (mainly floppy disk and hard drive) were included within the computer.
History
TTL Precursors
Although they did not contain any microprocessors, and were built around TTL Technology, Hewlett-Packard calculators as early as 1968 had various levels of programming such that they could be called microcomputers. The HP 9100B (1968) had conditional (if) statements, jump (GOTO) statements, registers that could be used as variables, and primitive subroutines. The programming language was similar to assembly language in many ways. Later models were adding more features, including the BASIC programming language (HP 9830A in 1971). Some models had tape storage and small printers. However, the displays were limited to a single line at a time. The HP 9100A was referred to as a personal computer in an advertisement in a 1968 issue of Science magazine, but that advertisement was quickly dropped. It is suspected that HP was reluctant to call them "computers" as it would complicate government contracting and export procedures.
The Datapoint 2200, made by CTC in 1970, is perhaps the best candidate for the title of "first microcomputer". Although it does not contain a microprocessor, its TTL processor's instruction set was the basis for the Intel 8008 processor's instruction set, and for practical purposes, the system behaves roughly as if it contained an 8008. This is because Intel was the contractor in charge of developing the Datapoint CPU, but CTC ultimately rejected the 8008 design because it needed the support of 20 carrier chips.
Another early system, the Kenbak-1, was released in 1971. Like the Datapoint 2200, it used discrete logic TTL technology instead of a microprocessor, but it functioned like a microcomputer in most respects. It was marketed as an educational tool and hobby, but it was not a commercial success; its production ceased shortly thereafter.
First microcomputers
In 1972, a French team led by François Gernelle within a small company, Réalisations et Études Électroniques (R2E), developed and patented a microprocessor-based computer, the 8-bit Intel 8008. The Micral-N was marketed in early 1973 as a Micro-ordinateur or microcomputer, primarily for scientific and process-technical applications. About a hundred Micral-N were installed over the next two years, followed by a new version based on the Intel 8080. Meanwhile, another French team developed the Alvan, a small office automation computer that found customers in banks and other sectors. The first version is based on LSI chips with an Intel 8008 peripheral controller (keyboard, monitor and printer), before adopting the Zilog Z80 as the main processor.
In 1972, a team at Sacramento State University led by Bill Pentz built the Sac State 8008 computer, capable of handling thousands of patient medical records. The Sac State 8008 was modeled after the Intel 8008. It had a complete system of hardware and software components: a disk operating system embedded in a series of programmable read-only memory (PROM) chips; 8 kilobytes of RAM; the IBM Basic Assembly Language (BAL), a hard drive, a color screen; a printer output; a 150 bits per second serial interface for connection to a host computer; and even the world's first microcomputer front panel.
In early 1973, Sord Computer Corporation (now Toshiba Personal Computer System Corporation) completed the SMP80/08, which used the Intel 8008 microprocessor. The SMP80/08, however, did not have a commercial release. After the first general purpose microprocessor was announced in April 1974, the Intel 8080, Sord announced the SMP80/x, the first microcomputer to use the 8080, in May 1974.
Virtually the first microcomputers were essentially boxes with lights and switches; you had to read and understand binary numbers and machine language to program and use them (the Datapoint 2200 was a notable exception, with a modern design based around a monitor, keyboard, and tape and disk drives). Of the first "switch boxes" for microcomputers, the MITS Altair 8800 (1975) was undoubtedly the most famous. Most of these early, simple microcomputers were sold as a set of electronic components that the buyer had to put together before the system could be used.
Microcomputers from the period 1971 to 1976 are sometimes called the first generation of microcomputers. Many companies like DEC, National Semiconductor, Texas Instruments offer their microcomputers for use in terminal control, peripheral device interface control, and industrial machinery control. There were also machines for engineering development and for personal hobby use. In 1975, Processor Technology designed the SOL-20, which consisted of a card, which included all the parts of the computer system. The SOL-20 incorporated software on EPROM which eliminated the need for rows of switches and lights. The MITS Altair played an instrumental role in arousing significant interest from hobbyists, which in turn led to the founding and success of many personal computer hardware and software companies, such as Microsoft and Apple Computer. Although the Altair itself was only moderately successful commercially, it helped spark a huge industry.
Home computers
In 1977, the introduction of the second generation, known as the home computer, made microcomputers considerably easier to use than their predecessors because their practical operation often required a thorough familiarity with practical electronics. The possibility of connecting a monitor (screen) or a television allows the visual manipulation of text and numbers. The BASIC language, which was easier to learn and use than pure machine language, became a standard feature. These features were already common in minicomputers, with which many hobbyists and early manufacturers were familiar.
In 1979, the release of the VisiCalc spreadsheet (initially for the Apple II) turned the microcomputer from a hobby for computer enthusiasts into a business tool. After the 1981 release of the IBM PC, the term personal computer (PC) became the generally used term for IBM PC compatible microcomputers.
In 2012, the credit card-sized single-board computer Raspberry Pi was released, directly inspired by Acorn Computers' BBC Micro (1981), and supported by BBC BASIC. a complete success to the point that, in addition to the Raspbian operating system, Microsoft supports it in Windows 10. A multitude of clones such as the Orange Pi and the Banana Pi were born in the wake of its success.[citation required]
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