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The evolution of the personal computer

Although it's hard for many of us to imagine life without desktop and laptop PCs at our disposal - not to mention other devices such as smartphones and tablets - it's worth remembering that it's really only over the last few decades that they've become commonplace both in the home and in the workplace. While the lineage of the modern-day personal computer stretches back several decades, it's only since the introduction of the microprocessor in the 1970s that these devices started to become accessible to domestic users.

From the bulky units of yesteryear to today's sleek and slender machines, the personal computer has come a long way in a relatively short space of time. With new technologies continuing to emerge all the time, it feels like now is a good point at which to look back at the evolution of the personal computer.

What makes a computer?

According to Historyofcomputer.org, any device capable of assisting people with carrying out calculations could be defined as a computer - so this would include such primitive devices as the abacus, for instance. Naturally, modern-day computer technology interprets information electronically, which enables it to conduct a massive number of calculations simultaneously. It's also worth noting that the graphics you see on your computer screen and the sound that comes out of its speakers are just abstractions of the calculations being made by your device - massive combinations of ones and zeros. Every image and every sound has its own binary code.

The prehistory of the personal computer

As an article from the Register points out, the heritage of the personal computer goes a long way - and in fact it could be argued that it stretches back several centuries. In the 16th century, Scottish mathematician John Napier invented a calculating machine capable of multiplying and dividing. Charles Babbage, in 1812, devised a calculating machine of his own, with the aim of printing out logarithm tables. It wasn't until 1819 he actually started work on making this a reality, however, and in 1822 he had invented his famous difference engine. Unfortunately, work on this fiendishly complex contraption was never completed and the project was abandoned in 1834. Nevertheless, it's not hard to see how both Napier's and Babbage's inventions fit into the early heritage of our own computerised age.

Early supercomputers

Early electronic computers were of course incredibly complicated - and huge, to boot. Using vacuum tubes, these devices were capable of solving an extensive range of computing problems, making them particularly impressive technological achievements considering the time at which they were developed. It's no coincidence that many of these computers started to appear at around the time of the Second World War - both the Allies and the Axis forces needed them to help glean a potentially crucial advantage over their adversaries.


The world's first programmable electromechanical digital computer, the Z3, arrived in 1941 and truly represented a major landmark in the evolution of computer technology. Although there is some debate about whether or not the Z3 can be bracketed alongside the early supercomputers which followed in its wake, it is probably fair to say that it helped to pave the way for them. First devised by Konrad Zuse and developed in wartime Berlin, the device - capable of crunching between five and 10 numbers per second - was created to analyse aircraft wing designs, although it was ostensibly a general-purpose machine. However, it was destroyed in an air raid in 1943.


In 1943, Post Office engineer Tommy Flowers and his team created Colossus, the first electronic programmable digital computer. This machine was needed to help decipher wartime messages in a quicker fashion than the electromechanical technology which had previous been used for the same purpose. As it turned out, Colossus was successful - it could compare messages at a rate of 5,000 characters per second, making it three times faster than the electromechanical systems. It wasn't until the 1970s, however, that Flowers' formerly top-secret work became public knowledge.


Developed to calculate ballistic firing missile tables for the US Army, Eniac is generally considered to be the world's first general purpose electronic computer. Developed by the University of Pennsylvania between 1943 and 1946, it was capable of being reprogrammed to solve a number of different problems and was first used as part of the effort to develop the hydrogen bomb. As work on the machine was completed after the end of the Second World War, there was less secrecy surrounding it than the other, broadly comparable devices which emerged at around the same time. To give some idea of the scale of ENIAC, it contained more than 17,500 vacuum tubes.

Computers start to go mainstream

According to Historylearningsite.co.uk, by 1955 there were still only 250 computers in use across the world. By 1980, there were some 30 million computers across the world. Early computers were bulky - making them totally impractical for domestic use - and notoriously unreliable. However, by the late 1950s, new and smaller computers were starting to emerge. This was because the valve had been replaced by the transistor. In turn, this made computers a much more attractive proposition to businesses, which started to buy them in greater numbers than previously.

The first business computers

The Register observes that the first business computer - the LEO 1 - arrived in the late 1940s and was developed by Lyons, better known for its chain of bakeries and restaurants. This device was spawned by Cambridge University's EDSAC, which had itself been influenced by the ENIAC project. Lyons was looking for ways to become more efficient, and its executives decided that a computer could help them to manage their costs more effectively. Although LEO 1 only had 31 basic instructions, Lyons was able to develop a coded program which it then used to track costs such as wages and raw materials.

Another important milestone in the development of business-orientated computer technology is the PDP-8, developed by Digital Equipment Corporation (DEC) and released in March 1965. Although - perhaps unsurprisingly - this device seems very bulky by today's standards, for its time it was a major step forward in computer design. Billed as the first 'minicomputer', the PDP-8 was roughly the same size as a fridge-freezer. Its relatively compact design helped to make it a major commercial success, with DEC selling more than 700,000 units from its release until its discontinuation in 1979 - when the first personal computers were coming to fruition.

The desktop PC arrives

By the latter end of the 1960s, the transistor was giving way to the microchip - and this opened the door to a whole host of computing innovations. The microprocessor followed in 1971. The Intel 4004 - the first microprocessor to be made commercially available - appeared towards the end of that year and was soon followed up with the Intel 8008, which cost just a tenth of its predecessor's price. The microprocessor was central to the advent of low-cost personal computers, which started to breach the mainstream market throughout the 1970s.

Xerox Alto/Star

Developed by Xerox engineers in the early '70s, the Alto was an experimental device designed as part of the company's experiments with new forms of user interface design. Although the Alto itself was never released commercially, a descendant - the Star - appeared in 1981. Perhaps its most important innovation was its graphical interface, which was the first to be controllable via a mouse. Nevertheless, the Star was largely confined to use among Xerox staff, although some went on to be donated to universities and other research faculties.

Altair 8800

In the early 1970s, personal computers were largely restricted to hobbyists. This was indeed the intended audience of the Altair 8800, which appeared in 1975. The do-it-yourself Altair kit was an instant hit, shifting several thousand units within the first month of sale. However, the Altair 8800 is perhaps best known for the Altair BASIC program - devised by Bill Gates and Paul Allen, who would of course later go on to establish Microsoft. Altair BASIC allowed users to write their own programs for the device in the BASIC programming language, and the Microsoft BASIC series followed in its wake.

Apple II

In 1975, Steve Jobs and Steve Wozniak founded their own company, Apple Computer. Two years later, the nascent Apple would release its first mass-produced home computer, the Apple II. Neatly contained within a plastic case, the computer also came equipped with a monitor and keyboard, as well as a floppy disk unit. It was also reasonably priced, which made it attractive to the mass market - and this is why it is considered to have done a lot to bring home computing into the mainstream. It also helped to establish Apple as one of the major firms in the growing technology sector.

IBM 5150

Although - as the Register notes - IBM was generally more concerned with producing mainframe and minicomputer technology in the early 1980s, it scored a surprise hit with the IBM 5150. Comprised of off-the-shelf parts, the 5150 appeared in August 1981 and quickly became popular with businesses. It's thought that part of the reason for the 5150's success is that until a respected and established brand name like IBM entered the fray, many businesses had been otherwise reticent to adopt the new computer technologies for their own use.

Graphical user interface and the next generation of PCs

With the technological capabilities of PCs accelerating at a rapid rate, a proliferation of new computer devices was starting to appear. The graphical user interface technology first pioneered by Xerox in the early 1970s would soon inspire Apple's Steve Jobs - who'd been taken on a tour of Xerox's Palo Alto research centre - to take it to the next level. This, in turn, prompted a technological arms race which would prove crucial in the further evolution of the personal computer.

Apple Macintosh

Launched in 1984, Apple's Macintosh was the first mass-market personal computer to feature both a graphical user interface and a mouse. The Mac would continue to dominate its field until the early 1990s and kick-started the drive towards desktop publishing. While the series went into a sustained decline in the 1990s, it enjoyed a revival towards the end of the decade with the launch of the iMac. This would, in turn, breathe new life into the ailing technology giant - but we'll come back to that later.

Microsoft Windows 3.0

Following the success of the Apple Macintosh, Microsoft sought to bring a swift end to its rival's growing dominance of the PC market. Along came Windows 3.0, which appeared in May 1990. The successor to Windows 2.1x, Windows 3.0 featured a redesigned user interface and a raft of other technical improvements. This was the first version of Windows to come pre-installed by manufacturers on brand-new PC hardware - making it the first Windows edition to see truly mainstream popularity. The best-selling Windows 3.1 followed in April 1992, by which point Windows was well-established as the operating system of choice for millions of users around the world.

Laptops, tablets, smartphones - and beyond

Although portable computer technology didn't really take off until the 1990s, there had been experiments with the concept years earlier. In fact, computer scientist Alan Kay - then a PhD candidate - came up with the concept for a laptop device, the Dynabook, intended to be aimed at children. Although the Dynabook never came to fruition, the Xerox NoteTaker followed in 1978 and included a monochrome display monitor, a mouse and a floppy disk drive. However, only 10 of these experimental units were ever made. Nevertheless, these early experiments would prove truly ground-breaking - as evidenced by the extraordinary range of handheld and portable computer technology available to consumers today.

Osborne 1

The world's first portable microcomputer, the Osborne 1, went on sale in April 1981. Based largely on the earlier Xerox NoteTaker, the device came in a closable plastic case and had its own handle for extra convenience. Although its bulky design hampered its commercial fortunes - it was about the same size as a sewing machine - around 11,000 Osborne 1 units were sold in the first eight months following its launch. The device also ran on the CP/M operating system, the rights to which Microsoft would later purchase and use when developing its own DOS software.

IBM/BellSouth Simon

By the mid-1990s, a number of personal digital assistant (PDA) devices had already appeared - including Apple's infamous Newton MessagePad, which was panned by critics and bombed commercially. However, it was IBM which took the next step in PDA technology with the creation of Simon, widely considered to be the world's first smartphone.

Although a prototype emerged in November 1992, it wasn't until August 1994 that IBM was sufficiently satisfied with the product to launch it commercially in partnership with US communications firm BellSouth. While Simon wasn't a runaway commercial hit - it was quietly discontinued in 1995 - it did lay the groundwork for other, more successful successors such as Nokia's 9000 Communicator, which appeared the following year.

Apple iPad

Although the Apple iPad is generally credited with bringing the tablet PC into the mainstream, it should be noted that it isn't the first of its kind - indeed, Apple's arch-rival Microsoft got its fingers badly burned when its own Tablet PC failed to catch on commercially. By 2010, Apple had well and truly regained its mojo after the success of the best-selling iPod personal music player and with the launch of the iPad, the company cemented its position at the top of the technology tree.

Launched in 2010, the iPad's touch interface is considered to be a major advance on earlier comparable technologies - indeed, its impact could reasonably be compared with that of the Macintosh's graphical user interface some 26 years earlier. In the year of its launch, according to data from market analytics firm IDC, the iPad accounted for a massive 83 per cent of global tablet sales. Naturally, a whole host of successors appeared in its wake - including the iPad 2, unveiled in March 2011.

Google Glass

To bring proceedings right up to the present day, it's worth taking a look at the one new technological innovation which has perhaps received more attention than any other in recent months. According to Techradar, rumours were circulating as early as 2012 that Google was working on its own wearable computer technology - this, of course, turned out to be Google Glass, which was launched in the US in February 2013.

In short, Google Glass brings data directly into the user's field of vision whilst dispensing with the need for laptop PCs or handheld portable technology devices. This optical head-mounted display unit offers a range of features, including photo and video capture. Users can also pair their headset with an Android phone to access other services such as Google Maps. It is also expected that a wide range of third-party apps will follow, potentially opening up a huge array of possibilities for the Google Glass technology.

A total of 8,000 users were picked by Google to buy the Google Glass Explorer, and as yet it is unclear just how much the device will cost when it reaches the mass market - which makes it difficult to predict whether or not it will be a commercial success. Nevertheless, it seems that with Google Glass we're venturing almost into the realms of science fiction. Whether or not it's a hit or a miss with the general public, it's highly likely that Google Glass will represent another major milestone on the technological road. It certainly appears that the next few years will be an exciting time to be a tech fan.