Computer HistoryBefore Personal Computers

Many discoveries and inventions have directly and indirectly contributed to the development of the personal computer as we know it today. Examining a few important developmental landmarks can help bring the entire picture into focus.

The first computers of any kind were simple calculators. Even these evolved from mechanical devices to electronic digital devices.

Timeline

The following is a timeline of some significant events in computer history. It is not meant to be complete, just a representation of some of the major landmarks in computer development:

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1617	John Napier creates "Napier's Bones," wooden or ivory rods used for calculating.
1642	Blaise Pascal introduces the Pascaline digital adding machine.
1822	Charles Babbage introduces the Difference Engine and later the Analytical Engine, a true general-purpose computing machine.
1906	Lee De Forest patents the vacuum tube triode, used as an electronic switch in the first electronic computers.
1936	Alan Turing publishes "On Computable Numbers," a paper in which he conceives an imaginary computer called the Turing Machine, considered one of the foundations of modern computing. Turing later worked on breaking the German Enigma code.
1936	Konrad Zuse begins work on a series of computers that will culminate in 1941 when he finishes work on the Z3. These are considered the first working electric binary computers, using electromechanical switches and relays.
1937	John V. Atanasoff begins work on the Atanasoff-Berry Computer (ABC), which would later be officially credited as the first electronic computer. Note that an electronic computer uses tubes, transistors, or other solid-state switching devices, whereas an electric computer uses electric motors, solenoids, and/or relays (electromechanical switches).
1943	Thomas (Tommy) Flowers develops the Colossus, a secret British code-breaking computer designed to decode secret messages encrypted by the German Enigma cipher machines.
1945	John von Neumann writes "First Draft of a Report on the EDVAC," in which he outlines the architecture of the modern stored-program computer.
1946	ENIAC is introduced, an electronic computing machine built by John Mauchly and J. Presper Eckert.
1947	On December 23, William Shockley, Walter Brattain, and John Bardeen successfully test the point-contact transistor, setting off the semiconductor revolution.
1949	Maurice Wilkes assembles the EDSAC, the first practical stored-program computer, at Cambridge University.
1950	Engineering Research Associates of Minneapolis builds the ERA 1101, one of the first commercially produced computers.
1952	The UNIVAC I delivered to the U.S. Census Bureau is the first commercial computer to attract widespread public attention.
1953	IBM ships its first electronic computer, the 701.
1954	A silicon-based junction transistor, perfected by Gordon Teal of Texas Instruments, Inc., brings a tremendous reduction in costs.
1954	The IBM 650 magnetic drum calculator establishes itself as the first massproduced computer, with the company selling 450 in one year.
1955	Bell Laboratories announces the first fully transistorized computer, TRADIC.
1956	MIT researchers build the TX-0, the first general-purpose, programmable computer built with transistors.
1956	The era of magnetic disk storage dawns with IBM's shipment of a 305 RAMAC to Zellerbach Paper in San Francisco.
1958	Jack Kilby creates the first integrated circuit at Texas Instruments to prove that resistors and capacitors can exist on the same piece of semiconductor material.
1959	IBM's 7000 series mainframes are the company's first transistorized computers.
1959	Robert Noyce's practical integrated circuit, invented at Fairchild Camera and Instrument Corp., allows printing of conducting channels directly on the silicon surface.
1960	Bell Labs designs its Dataphone, the first commercial modem, specifically for converting digital computer data to analog signals for transmission across its longdistance network.
1960	The precursor to the minicomputer, DEC's PDP-1, sells for $120,000.
1961	According to Datamation magazine, IBM has an 81.2% share of the computer market in 1961, the year in which it introduces the 1400 series.
1964	CDC's 6600 supercomputer, designed by Seymour Cray, performs up to three million instructions per seconda processing speed three times faster than that of its closest competitor, the IBM Stretch.
1964	IBM announces System/360, a family of six mutually compatible computers and 40 peripherals that can work together.
1964	Online transaction processing makes its debut in IBM's SABRE reservation system, set up for American Airlines.
1965	Digital Equipment Corp. introduces the PDP-8, the first commercially successful minicomputer.
1966	Hewlett-Packard enters the general-purpose computer business with its HP-2115 for computation, offering a computational power formerly found only in much larger computers.
1969	The root of what is to become the Internet begins when the Department of Defense establishes four nodes on the ARPAnet: two at University of California campuses (one at Santa Barbara and one at Los Angeles) and one each at SRI International and the University of Utah.
1971	A team at IBM's San Jose Laboratories invents the 8" floppy disk.
1971	The first advertisement for a microprocessor, the Intel 4004, appears in Electronic News.
1971	The Kenbak-1, one of the first personal computers, advertises for $750 in Scientific American.
1972	Hewlett-Packard announces the HP-35 as "a fast, extremely accurate electronic slide rule" with a solid-state memory similar to that of a computer.
1972	Intel's 8008 microprocessor makes its debut.
1972	Steve Wozniak builds his "blue box," a tone generator to make free phone calls.
1973	Robert Metcalfe devises the Ethernet method of network connection at the Xerox Palo Alto Research Center.
1973	The Micral is the earliest commercial, non-kit personal computer based on a microprocessor, the Intel 8008.
1973	The TV Typewriter, designed by Don Lancaster, provides the first display of alphanumeric information on an ordinary television set.
1974	Researchers at the Xerox Palo Alto Research Center design the Alto, the first workstation with a built-in mouse for input.
1974	Scelbi advertises its 8H computer, the first commercially advertised U.S. computer based on a microprocessor, Intel's 8008.
1975	Telenet, the first commercial packetswitching network and civilian equivalent of ARPAnet, is born.
1975	The January edition of Popular Electronics features the Altair 8800, which is based on Intel's 8080 microprocessor, on its cover.
1975	The visual display module (VDM) prototype, designed by Lee Felsenstein, marks the first implementation of a memory-mapped alphanumeric video display for personal computers.
1976	Steve Wozniak designs the Apple I, a single-board computer.
1976	The 5 1/4" flexible disk drive and disk are introduced by Shugart Associates.
1976	The Cray I makes its name as the first commercially successful vector processor.
1977	Tandy Radio Shack introduces the TRS-80.
1977	Apple Computer introduces the Apple II.
1977	Commodore introduces the PET (Personal Electronic Transactor).
1978	The VAX 11/780 from Digital Equipment Corp. features the capability to address up to 4.3GB of virtual memory, providing hundreds of times the capacity of most minicomputers.
1979	Motorola introduces the 68000 microprocessor.
1980	John Shoch, at the Xerox Palo Alto Research Center, invents the computer "worm," a short program that searches a network for idle processors.
1980	Seagate Technology creates the first hard disk drive for microcomputers, the ST-506.
1980	The first optical data storage disk has 60 times the capacity of a 5 1/4" floppy disk.
1981	Xerox introduces the Star, the first personal computer with a graphical user interface (GUI).
1981	Adam Osborne completes the first portable computer, the Osborne I, which weighs 24 lbs. and costs $1,795.
1981	IBM introduces its PC, igniting a fast growth of the personal computer market. The IBM PC is the grandfather of all modern PCs.
1981	Sony introduces and ships the first 3 1/2" floppy drives and disks.
1981	Philips and Sony introduce the CD-DA (compact disc digital audio) format.
1982	Sony is the first with a CD player on the market.
1983	Apple introduces its Lisa, which incorporates a GUI that's very similar to the one first introduced on the Xerox Star.
1983	Compaq Computer Corp. introduces its first PC clone that uses the same software as the IBM PC.
1984	Apple Computer launches the Macintosh, the first successful mouse-driven computer with a GUI, with a single $1.5 million commercial during the 1984 Super Bowl.
1984	IBM releases the PC-AT (PC Advanced Technology), three times faster than original PCs and based on the Intel 286 chip. The AT introduces the 16-bit ISA bus and is the computer on which all modern PCs are based.
1985	Philips introduces the first CD-ROM drive.
1986	Compaq announces the Deskpro 386, the first computer on the market to use what was then Intel's new 386 chip.
1987	IBM introduces its PS/2 machines, which make the 3 1/2" floppy disk drive and VGA video standard for PCs. The PS/2 also introduces the MicroChannel Architecture (MCA) bus, the first plug-and-play bus for PCs.
1988	Apple cofounder Steve Jobs, who left Apple to form his own company, unveils the NeXT.
1988	Compaq and other PC-clone makers develop Enhanced Industry Standard Architecture (EISA), which unlike MicroChannel retains backward compatibility with the existing ISA bus.
1988	Robert Morris's worm floods the ARPAnet. The 23-year-old Morris, the son of a computer security expert for the National Security Agency, sends a nondestructive worm through the Internet, causing problems for about 6,000 of the 60,000 hosts linked to the network.
1989	Intel releases the 486 (P4) microprocessor, which contains more than one million transistors. Intel also introduces 486 motherboard chipsets.
1990	The World Wide Web (WWW) is born when Tim Berners-Lee, a researcher at CERNthe high-energy physics laboratory in Genevadevelops Hypertext Markup Language (HTML).
1993	Intel releases the Pentium (P5) processor. Intel shifts from numbers to names for its chips after it learns it's impossible to trademark a number. Intel also releases motherboard chipsets and, for the first time, complete motherboards as well.
1995	Intel releases the Pentium Pro processor, the first in the P6 processor family.
1995	Microsoft releases Windows 95, the first mainstream 32-bit operating system, in a huge rollout.
1997	Intel releases the Pentium II processor, essentially a Pentium Pro with MMX instructions added.
1997	AMD introduces the K6, which is compatible with the Intel P5 (Pentium).
1998	Microsoft releases Windows 98.
1998	Intel releases the Celeron, a low-cost version of the Pentium II processor. Initial versions have no cache, but within a few months Intel introduces versions with a smaller but faster L2 cache.
1999	Intel releases the Pentium III, essentially a Pentium II with SSE (Streaming SIMD Extensions) added.
1999	AMD introduces the Athlon.
1999	The IEEE officially approves the 5GHz band 802.11a 54Mbps and 2.4GHZ band 802.11b 11Mbps wireless networking standards. The Wi-Fi Alliance is formed to certify 802.11b products, ensuring interoperability.
2000	The first 802.11b Wi-Ficertified products are introduced, and wireless networking rapidly builds momentum.
2000	Microsoft releases Windows Me (Millennium Edition) and Windows 2000.
2000	Both Intel and AMD introduce processors running at 1GHz.
2000	AMD introduces the Duron, a low-cost Athlon with reduced L2 cache.
2000	Intel introduces the Pentium 4, the latest processor in the Intel Architecture 32-bit (IA-32) family.
2001	Intel releases the Itanium processor, its first 64-bit (IA-64) processor for PCs.
2001	The industry celebrates the 20th anniversary of the release of the original IBM PC.
2001	Intel introduces the first 2GHz processor, a version of the Pentium 4. It took the industry 28 1/2 years to go from 108KHz to 1GHz, but only 18 months to go from 1GHz to 2GHz.
2001	Microsoft releases Windows XP Home and Professional, for the first time merging the consumer (9x/Me) and business (NT/2000) operating system lines under the same code base (an extension of Windows 2000).
2001	Atheros introduces the first 802.11a 54Mbps high-speed wireless chips, allowing 802.11a products to finally reach the market.
2002	Intel releases the first 3GHz-class processor, a 3.06GHz version of the Pentium 4. This processor also introduces Intel's Hyper-Threading (HT) technology (which enables a single processor to work with two application threads at the same time) to desktop computing.
2003	Intel releases the Pentium M, a processor designed specifically for mobile systems, offering extremely low power consumption that results in dramatically increased battery life while still offering relatively high performance. The Pentium M becomes the cornerstone of Intel's Centrino brand.
2003	AMD releases the Athlon 64, the first x86-64 (AMD64) 64-bit processor targeted at the mainstream consumer and business markets.
2003	The IEEE officially approves the 802.11g 54Mbps high-speed wireless networking standard, which uses the same 2.4GHz band as (and is backward-compatible with) 802.11b. 802.11g products reach the market quickly, some even before the official standard is approved.
2004	Intel introduces a version of the Pentium 4 codenamed Prescott, the first PC processor built on 90-nanometer technology.
2004	Intel introduces EM64T (Extended Memory 64 Technology), which is a 64-bit extension to Intel's IA-32 architecture. EM64T is software-compatible with and targeted at the same market as the x86-64 (AMD64) technology first released by AMD and is not compatible with the 64-bit Itanium.
2005	Microsoft releases Windows XP x64 Edition, which supports processors with AMD64 and EM64T extensions.
2005	The era of multicore PC processors begins as Intel introduces the Pentium D 8xx and Pentium Extreme Edition 8xx dual-core processors.
2005	AMD introduces the Athlon 64 X2 dual-core processors.

Mechanical Calculators

One of the earliest calculating devices on record is the abacus, which has been known and widely used for more than 2,000 years. The abacus is a simple wooden rack holding parallel rods on which beads are strung. When these beads are manipulated back and forth according to certain rules, several types of arithmetic operations can be performed.

Math with standard Arabic numbers found its way to Europe in the eighth and ninth centuries. In the early 1600s, a man named Charles Napier (the inventor of logarithms) developed a series of rods (later called Napier's Bones) that could be used to assist with numeric multiplication.

Blaise Pascal is usually credited with building the first digital calculating machine in 1642. It could perform the addition of numbers entered on dials and was intended to help his father, who was a tax collector. Then in 1671, Gottfried Wilhelm von Leibniz invented a calculator that was finally built in 1694. His calculating machine could not only add, but by successive adding and shifting, it could also multiply.

In 1820, Charles Xavier Thomas developed the first commercially successful mechanical calculator that could not only add but also subtract, multiply, and divide. After that, a succession of ever-improving mechanical calculators created by various other inventors followed.

The First Mechanical Computer

Charles Babbage, a mathematics professor in Cambridge, England, is considered by many to be the father of computers because of his two great inventionseach a different type of mechanical computing engine.

The Difference Engine, as he called it, was conceived in 1812 and solved polynomial equations by the method of differences. By 1822, he had built a small working model of his Difference Engine for demonstration purposes. With financial help from the British government, Babbage started construction of a full-scale model in 1823. It was intended to be steam-powered and fully automatic, and it would even print the resulting tables.

Babbage continued work on it for 10 years, but by 1833 he had lost interest because he now had an idea for an even better machine, something he described as a general-purpose, fully program-controlled, automatic mechanical digital computer. Babbage called his new machine an Analytical Engine. The plans for the Analytical Engine specified a parallel decimal computer operating on numbers (words) of 50 decimal digits and with a storage capacity (memory) of 1,000 such numbers. Builtin operations were to include everything that a modern general-purpose computer would need, even the all-important conditional function, which would allow instructions to be executed in an order depending on certain conditions, not just in numerical sequence. In modern computer languages, this conditional capability is manifested in the IF statement. The Analytical Engine was also intended to use punched cards, which would control or program the machine. The machine was to operate automatically by steam power and would require only one attendant.

The Analytical Engine is regarded as the first real predecessor to a modern computer because it had all the elements of what is considered a computer today. These included the following:

• An input device. Using an idea similar to the looms used in textile mills at the time, a form of punched cards supplied the input.

• A control unit. A barrel-shaped section with many slats and studs was used to control or program the processor.

• A processor (or calculator). A computing engine containing hundreds of axles and thousands of gears about 10 feet tall.

• Storage. A unit containing more axles and gears that could hold 1,000 50-digit numbers.

• An output device. Plates designed to fit in a printing press that were used to print the final results.

Alas, this potential first computer was never actually completed because of the problems in machining all the precision gears and mechanisms required. The tooling of the day was simply not good enough.

An interesting side note is that the punched card idea first proposed by Babbage finally came to fruition in 1890. That year a competition was held for a better method to tabulate the U.S. Census information, and Herman Hollerith, a Census Department employee, came up with the idea for punched cards. Without these cards, department employees had estimated the census data would take years to tabulate; with these cards they were able to finish in about six weeks. Hollerith went on to found the Tabulating Machine Company, which later became known as IBM.

IBM and other companies at the time developed a series of improved punch-card systems. These systems were constructed of electromechanical devices, such as relays and motors. Such systems included features to automatically feed in a specified number of cards from a "read-in" station; perform operations, such as addition, multiplication, and sorting; and feed out cards punched with results. These punched-card computing machines could process 50250 cards per minute, with each card holding up to 80-digit numbers. The punched cards not only provided a means of input and output, but they also served as a form of memory storage. Punched-card machines did the bulk of the world's computing for more than 50 years and gave many of the early computer companies their starts.

The development of mechanical computers culminated with the electromechanical systems developed by Konrad Zuse between 1936 and 1941, ending with what he called the Z3. These are considered the first working electric binary computers, using electromechanical switches and relays.

Electronic Computers

A physicist named John V. Atanasoff (with associate Clifford Berry) is officially credited with creating the first true digital electronic computer during 19371942, while working at Iowa State University. The Atanasoff-Berry Computer (called the ABC) was the first to use modern digital switching techniques and vacuum tubes as switches, and it introduced the concepts of binary arithmetic and logic circuits. This was made legally official on October 19, 1973, when following a lengthy court trial, U.S. Federal Judge Earl R. Larson voided the ENIAC patent of Eckert and Mauchly and named Atanasoff as the inventor of the first electronic digital computer.

Military needs during World War II caused a great thrust forward in the evolution of computers. In 1943, Tommy Flowers completed a secret British code-breaking computer called Colossus, which was used to decode German secret messages. Unfortunately, that work went largely uncredited because Colossus was kept secret until many years after the war.

Besides code-breaking, systems were needed to calculate weapons trajectory and other military functions. In 1946, John P. Eckert, John W. Mauchly, and their associates at the Moore School of Electrical Engineering at the University of Pennsylvania built the first large-scale electronic computer for the military. This machine became known as ENIAC, the Electrical Numerical Integrator and Calculator. It operated on 10-digit numbers and could multiply two such numbers at the rate of 300 products per second by finding the value of each product from a multiplication table stored in its memory. ENIAC was about 1,000 times faster than the previous generation of electromechanical relay computers.

ENIAC used approximately 18,000 vacuum tubes, occupied 1,800 square feet (167 square meters) of floor space, and consumed around 180,000 watts of electrical power. Punched cards served as the input and output; registers served as adders and also as quick-access read/write storage.

The executable instructions composing a given program were created via specified wiring and switches that controlled the flow of computations through the machine. As such, ENIAC had to be rewired and switched for each program to be run.

Although Eckert and Mauchly were originally given a patent for the electronic computer, it was later voided and the patent awarded to John Atanasoff for creating the Atanasoff-Berry Computer.

Earlier in 1945, the mathematician John von Neumann demonstrated that a computer could have a very simple, fixed physical structure and yet be capable of executing any kind of computation effectively by means of proper programmed control without the need for any changes in hardware.

In other words, you could change the program without rewiring the system. The stored-program technique, as von Neumann's ideas are known, became fundamental for future generations of high-speed digital computers and has become universally adopted.

The first generation of modern programmed electronic computers to take advantage of these improvements appeared in 1947. This group of machines included EDVAC and UNIVAC, the first commercially available computers. These computers included, for the first time, the use of true random access memory (RAM) for storing parts of the program and data that is needed quickly. Typically, they were programmed directly in machine language, although by the mid-1950s progress had been made in several aspects of advanced programming. The standout of the era is the UNIVAC (Universal Automatic Computer), which was the first true general-purpose computer designed for both alphabetical and numerical uses. This made the UNIVAC a standard for business, not just science and the military.