## The History of Computing Hardware (1960-Present)

Read this article to supplement the previous articles. As you see here, the history of computers is split into "generations". This course will primarily focus on the third generation of computers, which began in the 1960s, and the microcomputer technology of today, which has meant that computers are now present in the homes of many people across the world.

The history of computing hardware starting at 1960 is marked by the conversion from vacuum tube to solid-state devices such as the transistor and later the integrated circuit. By 1959 discrete transistors were considered sufficiently reliable and economical that they made further vacuum tube computers uncompetitive. Computer main memory slowly moved away from magnetic core memory devices to solid-state static and dynamic semiconductor memory, which greatly reduced the cost, size and power consumption of computers.

## Third generation

The mass increase in the use of computers accelerated with 'Third Generation' computers. These generally relied on Jack Kilby's invention of the integrated circuit (or microchip), starting around 1966 in the commercial market.

The first integrated circuit was produced in September 1958, and computers using them began to appear in the early 1960s, for example the 1961 Semiconductor Network Computer (Molecular Electronic Computer, Mol-E-Com), first monolithic integrated circuit general purpose computer (built for demonstration purposes, programmed to simulate a desk calculator) was built by Texas Instruments for the US Air Force.

Some of their early uses were in embedded systems, notably used by NASA for the Apollo Guidance Computer, by the military in the LGM-30 Minuteman intercontinental ballistic missile, the Honeywell ALERT airborne computer, and in the Central Air Data Computer used for flight control in the US Navy's F-14A Tomcat fighter jet.

An early commercial use was the 1965 SDS 92. IBM first used ICs in computers for the logic of the System/360 Model 85 shipped in 1969 and then made extensive use of ICs in its System/370 which began shipment in 1971.

The integrated circuit enabled the development of much smaller computers. The minicomputer was a significant innovation in the 1960s and 1970s. It brought computing power to more people, not only through more convenient physical size but also through broadening the computer vendor field. Digital Equipment Corporation became the number two computer company behind IBM with their popular PDP and VAX computer systems. Smaller, affordable hardware also brought about the development of important new operating systems such as Unix.

1969 Data General Nova

In November 1966, Hewlett-Packard introduced the 2116A minicomputer, one of the first commercial 16-bit computers. It used CTµL (Complementary Transistor MicroLogic) in integrated circuits from Fairchild Semiconductor. Hewlett-Packard followed this with similar 16-bit computers, such as the 2115A in 1967, the 2114A in 1968, and others.

## Mainframes and minicomputers

Time-sharing computer terminals connected to central computers, such as the TeleVideo ASCII character mode smart terminal pictured here, were sometimes used before the advent of the PC.

Computers were generally large, costly systems owned by large institutions before the introduction of the microprocessor in the early 1970s — corporations, universities, government agencies, and the like. Users were experienced specialists who did not usually interact with the machine itself, but instead prepared tasks for the computer on off-line equipment, such as card punches. A number of assignments for the computer would be gathered up and processed in batch mode. After the jobs had completed, users could collect the output printouts and punched cards. In some organizations, it could take hours or days between submitting a job to the computing center and receiving the output.

A more interactive form of computer use developed commercially by the middle 1960s. In a time-sharing system, multiple teleprinter terminals let many people share the use of one mainframe computer processor. This was common in business applications and in science and engineering.

A different model of computer use was foreshadowed by the way in which early, pre-commercial, experimental computers were used, where one user had exclusive use of a processor. Some of the first computers that might be called "personal" were early minicomputers such as the LINC and PDP-8, and later on VAX and larger minicomputers from Digital Equipment Corporation (DEC), Data General, Prime Computer, and others. They originated as peripheral processors for mainframe computers, taking on some routine tasks and freeing the processor for computation. By today's standards, they were physically large (about the size of a refrigerator) and costly (typically tens of thousands of US dollars), and thus were rarely purchased by individuals. However, they were much smaller, less expensive, and generally simpler to operate than the mainframe computers of the time, and thus affordable by individual laboratories and research projects. Minicomputers largely freed these organizations from the batch processing and bureaucracy of a commercial or university computing center.

In addition, minicomputers were more interactive than mainframes, and soon had their own operating systems. The minicomputer Xerox Alto (1973) was a landmark step in the development of personal computers, because of its graphical user interface, bit-mapped high resolution screen, large internal and external memory storage, mouse, and special software.

## Microprocessor and cost reduction

In the minicomputer ancestors of the modern personal computer, processing was carried out by circuits with large numbers of components arranged on multiple large printed circuit boards. Minicomputers were consequently physically large and expensive to produce compared with later microprocessor systems. After the "computer-on-a-chip" was commercialized, the cost to produce a computer system dropped dramatically. The arithmetic, logic, and control functions that previously occupied several costly circuit boards were now available in one integrated circuit which was very expensive to design but cheap to produce in large quantities. Concurrently, advances in developing solid state memory eliminated the bulky, costly, and power-hungry magnetic core memory used in prior generations of computers.

## Micral N

Micral N

In France, the company R2E (Réalisations et Etudes Electroniques) formed by five former engineers of the Intertechnique company, André Truong Trong Thi and François Gernelle introduced in February 1975 a microcomputer, the Micral N based on the Intel 8008. Originally, the computer had been designed by Gernelle, Lacombe, Beckmann and Benchitrite for the Institut National de la Recherche Agronomique to automate hygrometric measurements. The Micral N cost a fifth of the price of a PDP-8, about 8500FF (\$1300). The clock of the Intel 8008 was set at 500 kHz, the memory was 16 kilobytes. A bus, called Pluribus was introduced and allowed connection of up to 14 boards. Different boards for digital I/O, analog I/O, memory, floppy disk were available from R2E.

## Altair 8800 and IMSAI 8080

Development of the single-chip microprocessor was an enormous catalyst to the popularization of cheap, easy to use, and truly personal computers. The Altair 8800, introduced in a Popular Electronics magazine article in the January 1975 issue, at the time set a new low price point for a computer, bringing computer ownership to an admittedly select market in the 1970s. This was followed by the IMSAI 8080 computer, with similar abilities and limitations. The Altair and IMSAI were essentially scaled-down minicomputers and were incomplete: to connect a keyboard or teleprinter to them required heavy, expensive "peripherals". These machines both featured a front panel with switches and lights, which communicated with the operator in binary. To program the machine after switching it on the bootstrap loader program had to be entered, without error, in binary, then a paper tape containing a BASIC interpreter loaded from a paper-tape reader. Keying the loader required setting a bank of eight switches up or down and pressing the "load" button, once for each byte of the program, which was typically hundreds of bytes long. The computer could run BASIC programs once the interpreter had been loaded.

1975: Altair 8800

The MITS Altair, the first commercially successful microprocessor kit, was featured on the cover of Popular Electronics magazine in January 1975. It was the world's first mass-produced personal computer kit, as well as the first computer to use an Intel 8080 processor. It was a commercial success with 10,000 Altairs being shipped. The Altair also inspired the software development efforts of Paul Allen and his high school friend Bill Gates who developed a BASIC interpreter for the Altair, and then formed Microsoft.

The MITS Altair 8800 effectively created a new industry of microcomputers and computer kits, with many others following, such as a wave of small business computers in the late 1970s based on the Intel 8080, Zilog Z80 and Intel 8085 microprocessor chips. Most ran the CP/M-80 operating system developed by Gary Kildall at Digital Research. CP/M-80 was the first popular microcomputer operating system to be used by many different hardware vendors, and many software packages were written for it, such as WordStar and dBase II.

Many hobbyists during the mid-1970s designed their own systems, with various degrees of success, and sometimes banded together to ease the job. Out of these house meetings the Homebrew Computer Club developed, where hobbyists met to talk about what they had done, exchange schematics and software, and demonstrate their systems. Many people built or assembled their own computers as per published designs. For example, many thousands of people built the Galaksija home computer later in the early 1980s.

It was arguably the Altair computer that spawned the development of Apple, as well as Microsoft which produced and sold the Altair BASIC programming language interpreter, Microsoft's first product. The second generation of microcomputers, those that appeared in the late 1970s, sparked by the unexpected demand for the kit computers at the electronic hobbyist clubs, were usually known as home computers. For business use these systems were less capable and in some ways less versatile than the large business computers of the day. They were designed for fun and educational purposes, not so much for practical use. And although you could use some simple office/productivity applications on them, they were generally used by computer enthusiasts for learning to program and for running computer games, for which the personal computers of the period were less suitable and much too expensive. For the more technical hobbyists home computers were also used for electronics interfacing, such as controlling model railroads, and other general hobbyist pursuits.

## Microcomputer emerges

The Apple II, one of the "1977 Trinity". The drive shown is a model made for the Apple III.

The advent of the microprocessor and solid-state memory made home computing affordable. Early hobby microcomputer systems such as the Altair 8800 and Apple I introduced around 1975 marked the release of low-cost 8-bit processor chips, which had sufficient computing power to be of interest to hobby and experimental users. By 1977 pre-assembled systems such as the Apple II, Commodore PET, and TRS-80 (later dubbed the "1977 Trinity" by Byte Magazine) began the era of mass-market home computers; much less effort was required to obtain an operating computer, and applications such as games, word processing, and spreadsheets began to proliferate. Distinct from computers used in homes, small business systems were typically based on CP/M, until IBM introduced the IBM-PC, which was quickly adopted. The PC was heavily cloned, leading to mass production and consequent cost reduction throughout the 1980s. This expanded the PCs presence in homes, replacing the home computer category during the 1990s and leading to the current monoculture of architecturally identical personal computers.

## Timeline of computer systems and important hardware

Year Hardware
1959 Transistors: IBM 7090; IBM 1401
1960 DEC PDP 1
1961 Fairchild resistor transistor logic
1962 NPN transistor
1963 Mouse; CMOS patented
1964 CDC 6600; IBM Data Cell Drive
1965 DEC PDP 8; IBM 1130
1966 Integrated circuits: HP 2116A;[14] Apollo Guidance Computer
1967 Fairchild built first MOS; Englebart applies for mouse patent
1969 Data General Nova
1969 Honeywell 316
1970 DEC PDP 11
1971 8" floppy disk; ILLIAC IV
1972 Atari founded; Cray Research founded
1973 Micral first microprocessor PC
1974 Altair 8800; Data General Eclipse
1975 Olivetti P6060; Cray-1
1976 Tandem Computers
1977 Apple II; TRS-80 Model 1; Commodore PET; 5.25" floppy
1978 DEC VAX 11
1979 Atari 400, 800
1980 Sinclair ZX80, Seagate hard disk drive
1981 IBM PC, Acorn BBC Micro
1982 Commodore 64, Sinclair ZX Spectrum
1983 Apple Lisa; 3.5" floppy
1984 Apple Mac; Apple Lisa 2
1985 PC's Limited (renamed Dell Computer Corporation in 1988); Amiga 1000
1986 Tandem Nonstop VLX
1987 Thinking Machine CM2; Tera Computer Founded
1988 Dell
1989 NeXT
1990 ETA10; CD-R
1991 Apple Switches to PowerPC
1992 HP 95LX; Palmtop PC
1993 Intel PPGA
1994 VESA Local Bus
1995 IBM Deep Blue chess computer
1996 USB 1.0
1997 Compaq buys Tandem; CD-RW
1998 iMac
1999 First BlackBerry device (850)
2000 USB 2
2003 Arduino
2005 Mac Mini; World's first desktop dual-core CPU Athlon 64 X2
2006 Apple transition to Intel
2007 iPhone 1
2008 USB 3.0