A Brief History of Computing
Ancient Computing
Look up a definition of the verb "compute" and you will certainly find the synonym "calculate". Whatever you think of the various uses for present day computers (from producing original art to writing novels to composing and mixing music), computing machines were historically employed as an aid to making accurate (and fast) calculations.
This, of course, goes all the way back to the Abacus which probably dates as far back as the Babylonians a few hundred years before the Christian era. This simple but effective device, in skilled hands, certainly achieves rapid calculations and might be worthy of the title of the "Worlds First Computer".
The Abacus
Fast forward to 17th century France when, in 1645, we see the first mechanical calculating machine invented by Blaise Pascal and named the "Pascaline". By an ingenious arrangement of cog wheels and dials this early calculator could add and subtract. Shortly thereafter (in 1672), a German mathematician called Gottfried Leibnitz came up with another mechanical device that could add, subtract, multiply and divide. Unfortunately, both machines were too expensive to produce on a commercial basis and few were ever sold.
One of the features of any modern computer is the ability to run a pre-programmed set of instructions. Today there are many means of storing a program but, as far back as 1801, a man called Jacquard was programming textile patterns to be repeated indefinitely upon his looms. He used a series of boards with holes which triggered the lifting or dropping of hooks to produce the desired pattern in the weaving process.
Punched Hole Programming for Jacquard's Loom
To resume with the mechanical calculator theme, during the 19th century a certain Charles Babbage dedicated his life's work to designing and building a computer complete with the ability to be programmed to perform complex calculations. Work on his Difference Engine resulted in a machine weighing over fifteen tons but the project was never completed. Working replicas now stand in the Science Museum in London and in the Computer History Museum in California. Undeterred, Babbage continued to develop his designs for a new model, called the Analytical Engine, which occupied his genius for the rest of his life. Unlike the Difference Engine, the Analytical Engine used punch cards - somewhat like those used by Jacquard for his textile looms - to store and run the programs. Alas, once again, the machine was never built but it did provide an early conceptual model for the coming computer age.
Charles Babbage's Difference Engine No. 2
Babbage died in 1871 and around that time, across the Atlantic, a boy named Herman Hollerith would have been enjoying his school days. The connection between these two figures (as well as Jacquard) is, once again, the concept of the punched card. By 1890, Hollerith had already patented a machine for tabulating numerical statistics and was duly given the contract to build these machines to tabulate the results of the 1890 US Census. This time, the holes in the punched card permitted electrical contact and, conversely, prevented such contact where there were no holes. All kinds of data could be stored, organised and analysed quickly and efficiently using this method. To speed up the process of punching the holes, Hollerith also invented a key-punch panel, or "keyboard". The electrical contacts could be rearranged for different purposes thanks to another of Hollerith's inventions: a wiring panel called a Tabulator.
In 1911, Hollerith's company merged with three others to form a corporation called the Computing Tabulating Recording Company which was then renamed to (the easier to remember) International Business Machines ... IBM.
Early 20th Century Developments
Over the next 30 years or so, many innovations were taking place which, although not specifically part of any design for a "computer" (which still didn't have a formal definition at that time), were nevertheless important in the development of what we now understand a computer to be. These included advances in mathematics leading to the first programming languages (Kurt Gödel, Konrad Zuse and Alan Turing) and a gradual move from mechanical towards electronic devices.
As ever, necessity is the mother of invention and times of war always provide the necessity. During World War Two, Germany developed an encryption device (for coding secret messages) which was known, appropriately, as "Enigma". The ability to break the "unbreakable" Enigma codes was crucial to the Allied war effort so an elite code-breaking team was assembled at Bletchley Park (a.k.a. "Station X") in England. One of the great minds put to work on the project was that of the afore-mentioned Alan Turing: later to become known as the father of modern computer science.
The Enigma Machine
Turing was involved in adapting the design of a Polish decryption machine called a Bomba: the British version adopting the name, "Bombe". This electro-mechanical machine was hugely successful in decrypting Enigma encoded messages thereby thwarting many of the German military campaigns. Towards the end of the war, Bletchley Park was to see the development of what some consider to be the first electronic computer: "Colossus". The operative word we are looking at here is "electronic". The Colossus hardware was designed by a British Post Office (known today as British Telecom) engineer called Tommy Flowers and used electronic valve technology. This was not a general purpose computer (using a strict definition of the term) its purpose was specifically to break the new German Lorenz codes in use at the time. Nevertheless, it was electronic and it did run stored programs (punch-tape rather than punch-cards), thus it does lay claim to being one of the first electronic computers.
A Reconstruction of the Colossus at Bletchley Park
The Post-War Computer Age
After the war, the commercial powers recognised the potential of electronics in general, and computers in particular. It wasn't long before electronic valve (or vacuum tube) technology was appearing in both household and industrial applications, from televisions to industrial control systems. Following work by mathematician, John von Neumann, a standardised model for the design of the stored program computer architecture was adopted which has hardly changed since. This model included the basic components of a Control Unit, an Arithmetic Logic Unit, memory and input/output devices. Later, the Control and Logic Units became integrated in the Central Processing Unit (CPU).
The 1950's and 1960's saw the growth of big corporations manufacturing big computers - what became known as "mainframes". In those days, before Microsoft and Google, the most recognised names in the industry were IBM, Burroughs, Univac, Honeywell, and Control Data with ICL being the best known in the UK. The mainframe market started to collapse during the late 1980's and 90's until some of the larger institutions realised that there was still a place for the big beasts as large scale database servers. Today, IBM still dominates what is left of the mainframe market but its position as market leader in the industry as a whole has long since been usurped by Bill Gates and his Microsoft Corporation. We will take a look at how that happened a little later but, in the meantime, we will see how the trend for smaller and smaller gained momentum from the 1970's onwards.
A Mainframe Computer of the 1970's
Mini-Computers
Towards the end of the 1960's and early 1970's, new manufacturers were beginning to appear - at first in educational and research institutions - supplying smaller computers. Whereas the mainframe might be the size of a small truck and require its own temperature-controlled room, these new mini-computers might be smaller than a desk - might even fit under a desk - and they enabled the individual university department (or the smaller business) to have its own processing power.
By now, the vacuum tube had all but disappeared: replaced first by the transistor and later by the "Integrated Circuit" (IC) or "Microchip" which was - simply put - the integration of hundreds (then thousands, then millions) of tiny transistors on a single slice (or chip) of silicon. The constant rate of development of smaller, faster and more powerful components became predictable, resulting in Moore's Law which says that "the number of transistors that can be inexpensively placed on an integrated circuit is increasing exponentially, doubling approximately every two years". This law has been adhered to for half a century and shows no sign of being broken.
While IBM was still the "Daddy" in the mini-computer market too, other names such as Digital Equipment Corporation (DEC), Hewlett-Packard (HP) and Prime were also making an impact. So too was a new, cross-platform Operating system called Unix.
Front Panel of a DEC PDP-11
A quick pause for explanation here: for many years, each computer manufacturer would design and implement its own proprietary Operating System - that is the software that makes the computer hardware run (operate), rather than the software that produces the financial results or stores the personnel files in the database. The latter kind of software is called "Application Software".
To return to the main theme: some mini-computer manufacturers began to install a new operating system, written initially in 1969 by some employees at Bell Laboratories to run on a DEC PDP-7 mini, and eventually called Unix after name changes from Multics and Unics. This operating system later became freely available to all via the Open Software Foundation although, by then, many slightly different incarnations of it had been developed by different manufacturers. For example, we have AIX from IBM, HP-UX from HP, and Solaris from Sun. Later still, a version specifically designed to run on the Intel PC platform was developed by Linus Torvalds and named Linux after him. Incidentally, if you ever notice the date in some computer applications (notably internet forums) has been reset to January 1st. 1970 ... this is because that was the default start date of the original Unix - called the Unix epoch - and the system time on all Unix systems is counted in seconds from that date.
Personal Computers
1980's Onwards
Now that smaller organisations and academic units could afford the new mini-computers, the time was approaching for the first of the even smaller micro-computers to appear. To appear, not only in the individual classrooms or in the back office of the small trader, but also in the home. The first few turned up as kits to be assembled by hobbyists who had already performed outstandingly well as trailblazers for the electronic pocket-calculator industry. Indeed, as early as 1975, a DIY kit appeared in the US magazine, Popular Electronics. The magazine featured the Altair, a computer which had no keyboard and no display and could be programmed by means of flip-switches on the front panel (as could the PDP-11 in the picture above). This magazine article is very significant in the history of computing because it was read by the young Bill Gates who saw an opportunity to sell an interpreter for the BASIC programming language developed by himself and Paul Allen. Bill and Paul called their fledgling software company "Microsoft".
But it was not until the 80's that the Personal Computer revolution really gathered momentum. In 1980 a British entrepreneur inventor called Clive Sinclair launched a sub-£100 home computer called the ZX-80 (£99 pre-built and £79 in kit form). This was followed in 1982 by the very successful ZX Spectrum (I had one of these).
The 1982 Sinclair ZX Spectrum
The new generation home computers were starting to resemble the present-day concept of a PC: they had a keyboard which could be used to write programs (again, in the BASIC language) and to control the programs while they were running. Software could be stored and loaded from magnetic media (in those days: a cassette tape recorder), and the results output to a display (a regular TV set). Sinclair had stiff competition from the likes of Commodore, Amstrad and Atari. In all cases, the attraction of these pieces of advanced home electronics was not so much that they were programmable computers but probably more to do with the fact that they could run games. This was also the height of the Arcade Game craze which saw millions of boys-at-heart pumping tons of loose change into free-standing consoles in pubs and commercial arcades.
It would have been unthinkable for the megalithic corporate, IBM, to sit back and watch all these new start-up companies grab the growing microcomputer market ... and they didn't. Instead they showed the world how it should be done when they released what was to become the universal standard for small, single-user computers: the IBM PC. After that, it was either [IBM] PC compatible or it was an Apple. Yes, the truly innovative Steve Jobs and his team over Apple were, for a generation, the only ones to offer a real alternative to the PC architecture. Apple did their own thing, and did it exceedingly well - offering, from the very early days, colour graphics and a applications running in windows - but IBM had the muscle. Soon, the clones began to appear - the first 100% compatible product coming from Compaq - but the clones were all PC clones, not Apple clones.
The IBM PC
While IBM were powerful, they were not above a certain haughty arrogance in underestimating the threat from the clone manufacturers and software developers. During development, the new PC needed an operating system and, instead of producing one in-house, they offered the contract to Bill Gates' Microsoft after negotiations with Digital Research had broken down. In the background, Gates had secured the rights to a "quick and dirty" version of the then popular CP/M operating system. He provided this to IBM and they called it "PC-DOS" but the clever young Gates had retained the rights and continued to market the operating system, as MS-DOS, to the other clone manufacturers. Indeed, our Bill was never above lifting someone else's good idea and when the first version of the MS-DOS based Graphical User Interface (GUI) - called "Microsoft Windows" - was released in 1985, many Apple users noted the distinct similarity to the Lisa GUI they had been working with for some time already. This is not to say that Steve Jobs was above a little idea-snatching himself: Lisa was also remarkably similar to a GUI he had seen in use at the Xerox corporation in 1979. Indeed, some of the developers who had worked for Xerox subsequently joined Jobs at Apple.
So, by the 1990's IBM was finally in decline - never really able to capitalise on the huge PC market they had helped to spawn - but it remains dominant in the still-profitable mainframe business. Other large manufacturers fared even worse: Digital Equipment Corporation (DEC) was swallowed by Compaq who, in turn were swallowed by HP. Sun has remained resolutely in the mid-to-large scale computer market with their Solaris (Unix) based servers. Linux has threatened to catch on in a big way but has never really attained much penetration outside the internet web server market. The real winners since the late 1980's to the present day have been Microsoft. They are today what IBM used to be in the 1970's and this year Bill Gates finally stepped down from his ivory tower and bequeathed his legacy to those who have helped him build the company. Perhaps he did so just in time because, just as Microsoft crept in under the nose of IBM, other pretenders are trying on the Microsoft footwear for size. Chief contender right now appears to be Google: watch this space!