Way back in early history, when people relied mainly on their brains to perform calculations, people used their fingers, pebbles, and tally sticks for computing purposes.
Various attempts were made to build general-purpose programmable computers from the same mechanical devices used in calculators. But the problems posed by the lack of technology at the time were not satisfactorily solved until the introduction of electronic computing techniques in the mid-20th century. Between Pascal’s invention and around 1820 there were about 25 manufacturers of calculating machines; most of them were the work of one man. Few of them worked correctly and even less actually reached the manufacturing line.
In the mid-19th century Charles Babbage, a visionary British mathematician at Cambridge University, designed the first computers to perform multistep operations automatically.
The technologies were entirely mechanical. He called this first computing machine the Difference Engine, and it was intended to compute and print mathematical tables automatically. The Difference Engine performed only one arithmetic operation: addition. Babbage constructed a small portion of his first Difference Engine in 1832, which served as a demonstration prototype.
The first widely known general-purpose electronic computer was the Electronic Numerical Integrator and Calculator (ENIAC) that John W. Mauchly and J. Presper Eckert built at the University of Pennsylvania.
The primary motivation for the ENIAC was the need to construct ballistic tables for the U.S. Army. Work began on the ENIAC in 1943 and in 1946 it was completed. It was an enormous machine weighing about 30 tons and filling a 30 by 50 foot room. It contained 1,500 electromechanical relays and over 18,000 vacuum tubes and when it was switched on it consumed 150,000 watts of energy. Despite its enormous size it stored only the equivalent of 80 characters of information. However, it was substantially faster than any previous computer.
The idea of storing programs and their data in the same high-speed memory – the stored-program concept – was first put forth by von Neumann in a publication entitled, “First Draft of a Report on the EDVAC” (Electronic Discrete Variable Computer). The IAS machine in its overall design is quite modern, and can be regarded as the prototype of most subsequent general-purpose computers. It had the general structure depicted in Figure 4. It had a CPU (Central Processing Unit) for executing instructions, a main memory for storing active programs, a secondary memory for backup storage, and miscellaneous input-output equipment.
The IBM PC series was introduced in 1981 and quickly became the de facto standard for this class of machine. IBM made a smart decision by making the architecture of the PC open, meaning its design specifications were available to other manufacturers of computers and software. As a result of this decision the IBM PC became very popular and many versions of it, PC clones, were produced by others.
Many other significant achievements have occurred in the PC era and continue to occur with the widespread use of the Internet and networked computers. Here are a few other notable historical achievements having to do with PC’s:
o 1976 – The Cray 1 Supercomputer was the first commercially developed supercomputer. It contained 200,000 IC’s and was cooled by Freon.
o 1977 – Apple II computer introduced.
o 1979 – Commodore Pet released, with 1 MHz computing power, 8K RAM, cassette deck, and 9″ monitor displaying monochrome text.
o 1979 – The compact disk was invented.
o 1982 – The TCP/IP network communications protocol was established and the “Internet” was formed as a connected set of networks using TCP/IP.
o 1982 – Commodore 64 released, costing just ï¿½595.
o 1982 – Compaq releases their IBM PC compatible, the Compaq Portable.
o 1983 – The IBM XT is released. This machine had a 10MB hard disk, 128KB of RAM, one floppy drive, a mono monitor, and a printer, all for ï¿½5000. What a bargain!
o 1984 – Apple Macintosh released.
o 1985 – Microsoft Windows launched, but not really widely used until version 3 in 1990.
o 1987 – IBM introduced its PS/2 System which was very successful, selling over 2 million machines in less than 2 years.
o 1989 – The World Wide Web (WWW) is invented by Tim Berners-Lee who saw the need for global information exchange that would allow physicists to collaborate on research. The Web was a result of the integration of hypertext and the Internet. Hyperlinked pages could not only provide information but could provide transparent access to other pages of information as well as other Internet facilities such as ftp, telnet, Gopher, WAIS, and USENET. The Web started out as a text-only interface but NCSA Mosaic, an early browser, later presented a graphical interface for it and its popularity exploded as it became accessible to the novice user. The explosion of the Web started in earnest during 1993 and in a single year Web traffic increased by 300,000%.
o 1990 – Windows 3.0 introduced by Microsoft. This graphical user interface OS offered true multi-tasking, meaning you could run multiple programs at the same time.
o 1993 – The Pentium microprocessor released by Intel. It was only available at that time in 60 and 66 MHz versions.
o 1995 – Windows 95 operating system released by Microsoft.
o 1995 – Pentium Pro microprocessor released.
o 1997 – Pentium MMX (166 and 200 MHz) released.
o 1997 – Pentium II (233, 266, and 300 MHz) released.
o 1998 – Windows 98 released.
o 1999 – Linux, a free alternative operating system to Microsoft’s Windows, is estimated to be running on over 10 million computers worldwide.