The Commodore 64 was one of the most popular microcomputers of its era, and is the best selling model of home computer of all time. A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s ^[1]

A microcomputer^[2] is a computer with a microprocessor as its central processing unit. A computer is a Machine that manipulates data according to a list of instructions. A microprocessor incorporates most or all of the functions of a Central processing unit (CPU on a single Integrated Another general characteristic of these computers is that they occupy physically small amounts of space when compared to mainframe and minicomputers. Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers (in the generic sense). A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated ^[3][4]

Origins

The term "Microcomputer" came into popular use after the introduction of the minicomputer, although Isaac Asimov used the term microcomputer in his short story "The Dying Night" as early as 1956 (published in The Magazine of Fantasy and Science Fiction in July that year). A minicomputer (colloquially mini) is a class of multi-user Computers that lies in the middle range of the computing spectrum in between the largest Multi-user Isaac Asimov (c January 2 1920 &ndash April 6 1992 ˈaɪzək ˈæzɪmʌv originally Исаак Озимов but now transcribed into Russian as, was a Russian The Magazine of Fantasy & Science Fiction (later Fantasy & Science Fiction and usually referred to as just F&SF) is a digest-size Most notably, the microcomputer replaced the many separate components that made up the minicomputer's CPU with a single integrated microprocessor chip. Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside

The earliest models often sold as kits to be assembled by the user, and came with as little as 256 bytes of RAM, and no input/output devices other than indicator lights and switches. A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science. In Computing, input/output, or I/O, refers to the communication between an Information processing system (such as a Computer) and the outside However, as microprocessors and semiconductor memory became less expensive from the early-to-mid-1970s onwards, microcomputers in turn grew faster and cheaper. Semiconductor memory is Computer memory implemented on a Semiconductor -based Integrated circuit. This resulted in an explosion in their popularity during 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, Northstar,South West Technical Products, Ohio Scientific, Altos, Morrow Designs and others produced systems designed either for a resourceful end user or consulting firm to deliver business systems such as accounting, database management, and word processing to small businesses. Cromemco was a Mountain View California Microcomputer company known for its high-end Z80 -based S-100 bus computers in the early days of the Northstar ( Jean-Paul Beaubier) is a Canadian mutant and one of the few openly gay characters in the Marvel Universe Ohio Scientific Inc (also known as Ohio Scientific Instruments) was a United States Computer Company that built and marketed computers from Altos is a district and locality of the Cordillera Department, Paraguay. George Morrow (c 1934 - May 7, 2003) was part of the early Microcomputer industry in the United States. This allowed businesses unable to afford leasing of a minicomputer or time-sharing service the opportunity to automate business functions, without (usually) hiring a full-time staff to operate the computers. A representative system of this era would have used an S100 bus, an 8-bit processor such as a Z80, and either CP/M or MP/M operating system. CP/M (Control Program for Microcomputers is an Operating system originally created for Intel 8080 / 85 based Microcomputers by Gary Kildall MP/M was the multi-user version of the CP/M Operating system, created by Digital Research developer Tom Rolander in 1979

The increasing availability and power of desktop computers for personal use attracted the attention of more software developers. A desktop computer is a Personal computer (PC in a form intended for regular use at a single location as opposed to a mobile Laptop or portable computer As time went on and the industry matured, the market for personal (micro)computers standardized around IBM PC compatibles running MS-DOS (and later Windows). A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. MS-DOS (short for M icro' s' oft D isk O perating S ystem is an Operating system commercialized by Microsoft. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft.

Modern desktop computers, video game consoles, laptop computers, tablet PCs, and many types of handheld devices, including mobile phones and pocket calculators, as well as industrial embedded systems, may all be considered examples of microcomputers according to the definition given above. A laptop computer, also known as a notebook computer, is a small Personal computer designed for mobile use. A Tablet PC is a Notebook or slate-shaped Mobile computer, equipped with a Touchscreen or Graphics tablet/screen hybrid technology which allows A mobile device (also known as cellphone device, handheld device, handheld computer, "Palmtop" or simply handheld) is a pocket-sized A calculator is device for performing mathematical calculations distinguished from a Computer by having a limited problem solving ability and an interface optimized for interactive An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints

Colloquial use of the term

Everyday use of the expression "microcomputer" (and in particular the "micro" abbreviation) has declined significantly from the mid-1980s onwards, and is no longer commonplace. The 1980s was the decade spanning from January 1 1980 to December 31 1989. It is most commonly associated with the first wave of all-in-one 8-bit home computers and small business microcomputers (such as the Apple II, Commodore 64, BBC Micro, and TRS 80). Eight-bit CPUs normally use an 8-bit data bus and a 16-bit address bus which means that their Address space is limited to 64 KBs This is not a "natural A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s TRS-80 was Tandy Corporation 's desktop Microcomputer model line sold through Tandy's Radio Shack stores in the late 1970s and early Although—or perhaps because—an increasingly diverse range of modern microprocessor-based devices fit the definition of "microcomputer," they are no longer referred to as such in everyday speech.

In common usage, "microcomputer" has been largely supplanted by the description "personal computer" or "PC," which describes that it has been designed to be used by one person at a time. A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated IBM first promoted the term "personal computer" to differentiate themselves from other microcomputers, often called "home computers. A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s " and also IBM's own mainframes and minicomputers. Unfortunately for IBM, the microcomputer itself was widely imitated, as well as the term. The component parts were commonly available to manufacturers and the BIOS was reverse engineered through cleanroom design techniques. In Computing, the BIOS (ˈbaɪoʊs Reverse engineering (RE is the process of discovering the technological principles of a device object or system through analysis of its structure function and operation Clean room design (also known as the Chinese wall technique is the method of copying a design by Reverse engineering and then recreating it without infringing IBM PC compatible "clones" became commonplace, and the terms "Personal Computer," and especially "PC" stuck with the general public. IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. .

Description

Monitors, keyboards and other devices for input and output may be integrated or separate. Computer memory in the form of RAM, and at least one other less volatile, memory storage device are usually combined with the CPU on a system bus in a single unit. In Personal computers the Front Side Bus ( FSB) is the bus that carries data between the CPU and the northbridge. Other devices that make up a complete microcomputer system include, batteries, a power supply unit, a keyboard and various input/output devices used to convey information to and from a human operator (printers, monitors, human interface devices) Microcomputers are designed to serve only a single user at a time, although they can often be modified with software or hardware to concurrently serve more than one user. Power supply is a reference to a source of Electrical power. A device or system that supplies Electrical or other types of Energy to an output load A visual display unit, often called simply a monitor or display, is a piece of Electrical equipment which displays images generated from the Video A human interface device or HID is a type of Computer device that Interacts directly with and most often takes Input from Microcomputers fit well on or under desks or tables, so that they are within easy access of the user. Bigger computers like minicomputers, mainframes, and supercomputers take up large cabinets or even a dedicated room. A minicomputer (colloquially mini) is a class of multi-user Computers that lies in the middle range of the computing spectrum in between the largest Multi-user Mainframes (often colloquially referred to as Big Iron) are Computers used mainly by large organizations for critical applications typically bulk data A supercomputer is a Computer that is at the frontline of processing capacity particularly speed of calculation (at the time of its introduction

A microcomputer comes equipped with at least one type of data storage, usually RAM. Although some microcomputers (particularly early 8-bit home micros) perform tasks using RAM alone, some form of secondary storage is normally desirable. Computer data storage, often called storage or memory, refers to Computer components devices and recording media that retain digital In the early days of home micros, this was often a data cassette deck (in many cases as an external unit). A cassette deck is a type of Tape recorder for playing or recording audio Compact cassettes A deck was formerly distinguished from a recorder Later, secondary storage (particularly in the form of floppy disk and hard disk drives) were built in to the microcomputer case itself. A floppy disk is an increasingly Obsolete data storage medium that is composed of a disk of thin flexible ("floppy" Magnetic storage medium encased A hard disk drive ( HDD) commonly referred to as a hard drive, hard disk, or fixed disk drive, is a Non-volatile storage device

History

A collection of early microcomputers, including a Processor Technology SOL-20 (top shelf, right), an MITS Altair 8800 (second shelf, left), a TV Typewriter (third shelf, center), and an Apple I in the case at far right. Bob Marsh founded Processor Technology Corporation (a Microcomputer company in April 1975 The MITS Altair 8800 was a Microcomputer design from 1975 based on the Intel 8080 CPU and sold as a mail-order kit through advertisements in The TV Typewriter was a video terminal that could display 2 pages of 16 lines of 32 upper case characters on a standard television The Apple I, also known as the Apple-1, was an early Personal computer.

Although they contained no microprocessors but were built around TTL logic, Hewlett Packard Calculators as far back as 1968 had various levels of programmability such that they could be called microcomputers. The HP 9100B (1968) had rudimentary conditional (IF) statements, statement line numbers, Jump statements (Go_to), registers that could be used as variables, and primitive subroutines. GOTO is a statement found in many computer Programming languages It is a combination of the English words go and to The programming language resembled Assembly language in many ways. See the terminology section below for information regarding inconsistent use of the terms assembly and assembler Later models incrementally added more features, including the BASIC programming language (HP 9830A in 1971). In Computer programming, BASIC (an Acronym for Beginner's All-purpose Symbolic Instruction Code) is a family of High-level programming languages Some models had tape storage and small printers. However, displays were limited to a single line at a time. [1] The HP 9100A was referred to as a personal computer in an advertisement in a 1968 Science magazine^[5] but that advertisement was quickly dropped. The Hewlett-Packard 9100A is an early computer/calculator first appearing in 1968. A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated Science is the Academic journal of the American Association for the Advancement of Science and is considered one of the world's most prestigious Scientific ^[6] It is suspected that HP was reluctant to call them "computers" because it would complicate government procurement and export procedures.

The Datapoint 2200, made by CTC in 1970, is perhaps the best candidate for the title of "first microcomputer". Technical description The Datapoint 2200 had a built-in full-travel keyboard, a built-in 12-line 80-column green screen monitor and two cassette Datapoint Corporation, originally known as Computer Terminal Corporation (CTC, was a computer company based in San Antonio Texas, United States. While it contains no microprocessor, it used the 4004 programming instruction set and its custom TTL logic was the basis for the Intel 8008, and for practical purposes the system behaves approximately as if it contains an 8008. The Intel 4004 is a 4-bit Central processing unit (CPU released by Intel Corporation in 1971 An instruction set is a list of all the instructions and all their variations that a processor can execute The Intel 8008 was an early byte-oriented Microprocessor designed and manufactured by Intel and introduced in April 1972 This is because Intel was the contractor in charge of developing the Datapoint's CPU but ultimately CTC rejected the 8008 design because it needed 20 support chips. ^[7]

Another early system, the Kenbak-1, was released in 1971. The Kenbak-1 is considered by the Computer History Museum and the American Computer Museum to be the world's first " Personal computer " (however Like the Datapoint 2200, it used discrete TTL logic instead of a microprocessor, but functioned like a microcomputer in most ways. It was marketed as an educational and hobbyist tool, but was not a commercial success; production ceased shortly after introduction. [2]. Another system of note is the Micral-N, introduced in 1973 by a French company and powered by the 8008; it was the first microcomputer sold all assembled and not as a construction kit. According to the Computer History Museum the Micral N was the earliest commercial non-kit personal computer based on a Microprocessor, the Intel 8008.

Virtually all early microcomputers were essentially boxes with lights and switches; one had to read and understand binary numbers and machine language to program and use them (the Datapoint 2200 was a striking exception, bearing a modern design based around a monitor, keyboard, and tape and disk drives). Of the early "box of switches"-type microcomputers, the MITS Altair 8800 (1975) was arguably the most famous. The MITS Altair 8800 was a Microcomputer design from 1975 based on the Intel 8080 CPU and sold as a mail-order kit through advertisements in Most of these simple, early microcomputers were sold as electronic kits--bags full of loose components which the buyer had to solder together before the system could be used. An electronic Kit is a package of Electrical components used to build an electronic device.

The period from about 1971 to 1976 is sometimes called the first generation of microcomputers. These machines were for engineering development and hobbyist personal use. In 1975, the Processor Technology SOL-20 was designed, which consisted of a single board which included all the parts of the computer system. Bob Marsh founded Processor Technology Corporation (a Microcomputer company in April 1975 Bob Marsh founded Processor Technology Corporation (a Microcomputer company in April 1975 The SOL-20 had built-in EPROM software which elimated the need for rows of switches and lights. Bob Marsh founded Processor Technology Corporation (a Microcomputer company in April 1975 The MITS Altair just mentioned played an instrumental role in sparking significant hobbyist interest, which itself eventually led to the founding and success of many well-known personal computer hardware and software companies, such as Microsoft and Apple Computer. The MITS Altair 8800 was a Microcomputer design from 1975 based on the Intel 8080 CPU and sold as a mail-order kit through advertisements in A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated Microsoft Corporation is an American multinational Computer technology Corporation, which rose to dominate the Home computer Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics Although the Altair itself was only a mild commercial success, it helped spark a huge industry.

1977 saw the introduction of the second generation, known as home computers. A home computer was a class of Personal computer entering the market in 1977 and becoming common during the 1980s These were considerably easier to use than their predecessors, whose operation often demanded thorough familiarity with practical electronics. The ability to connect to a monitor (screen) or TV set allowed for visual manipulation of text and numbers. The BASIC programming language, which was easier to learn and use than raw machine language, became a standard feature. In Computer programming, BASIC (an Acronym for Beginner's All-purpose Symbolic Instruction Code) is a family of High-level programming languages These features were already common in minicomputers, which many hobbyists and early manufactures were familiar with. A minicomputer (colloquially mini) is a class of multi-user Computers that lies in the middle range of the computing spectrum in between the largest Multi-user

1979 saw the launch of the VisiCalc spreadsheet (initially for the Apple II) that first turned the microcomputer from a hobby for computer enthusiasts into a business tool. VisiCalc was the first Spreadsheet program available for personal computers A spreadsheet is a Computer application that simulates a paper worksheet After the 1981 release by IBM of their IBM PC, the term Personal Computer became generally used for microcomputers compatible with the IBM PC architecture (PC compatible). A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT.

References and footnotes

See also

• Personal Computer
• Lists of microcomputers
• Minicomputer
• Mainframe computer
• Supercomputer
• History of computing hardware (1960s-present)