Intel 4004 The first ever ‘microprocessor,’ the Intel 4004 heralded the dawn of the personal computing age. The Intel 4004 had an initial clock speed of 108KHz and 2,300 individual transistors compared to 3.9GHz and 1.4 billion transistors on the latest chips.

Altair 8800Widely regarded as the first personal computer, the Altair 8800 was ground breaking. It was sold in kit form, containing four separate circuit boards and many different parts. Microsoft was founded to supply a BASIC interpreter for the Altair.

The Macintosh Despite the Xerox Alto introducing such concepts more than a decade earlier, the Mac became the first mass-market computer to ship with a graphical user interface and a mouse.

GRiD Compass Debate rages over what was the first ‘laptop’, but we’re giving the honour to the GRiD Compass, the first vaguely mainstream device to use the familiar clamshell design. It cost up to $10,000, and was used by NASA.

Windows 1.0The forefather of the operating system used on the vast majority of today’s PCs, Windows 1.0 replaced MS-DOS’ typed commands with point-and-click ‘windows’, including drop-down menus, scrollbars and more.

Xerox AltoThe Xerox Alto was the first computer with a graphical user interface (GUI) – complete with desktop, folders and icons – and was the first to be controlled by a mouse. It was never sold to the public, though.

The IBM PC‘Chess’ was eventually unveiled as the IBM 5150 PC in August 1981. It used an Intel 8088 CPU running at 4.77MHz and up to 64KB of RAM. Its impact was such that, in 1982, Time declared the home computer as its Person of the Year.

Apple IIArguably, the first commercially successful PC, the Apple II launched with an integrated QWERTY keyboard, colour graphics and a cassette tape deck for loading programs. The first model sported a 1MHz processor and 4KB of RAM.

The birth of MS-DOSIn July 1980, IBM approached Microsoft to provide an operating system for a forth- coming personal computer, codenamed ‘Chess’ Microsoft acquired the rights to 86-DOS from Seattle Computer Products and adapted it to IBM’s needs. The Microsoft Disk Operating System was born.

CPU

4.77MHz

RAM

64KB

Mosaic (Netscape Navigator)Mosaic, later renamed Netscape Navigator, was the first popular web browser, and a major driver of the home PC boom that was to follow. In 1994, it accounted for 90% of web use, but by 2002, Internet Explorer had 95% market share.

Attack of the clones Using a combination of Intel processors and MS-DOS, several manufacturers created IBM PC-compatible computers. Companies such as Compaq and HP created so-called ‘clones’ that could run the same software as IBM’s machines, but were often much cheaper.

The micro machinesAlthough not IBM compatibles, so-called ‘micro machines’ such as the ZX Spectrum, Commodore 64 and BBC Micro became the first personal computer in many British homes.

Microsoft WordInitially released for MS-DOS back in 1983, Microsoft Word has become one of the most used applications of all time. It, of course, formed part of the first Office suite, alongside Excel and PowerPoint in 1990.

CPU

1MHzRAM

4KB

Windows 3.xThe 1990 launch of Windows 3.0 and subsequent 1992 arrival of Windows 3.1 coincided with a steep upswing in PC ownership. Concepts such as the Program Manager and File Manager were introduced for the first time.

Windows 95The PC came of age with Windows 95, which sold seven million copies in its first five weeks. It introduced the Start button and desktop that are still in use today. It’s undoubtedly the most influential operating system ever made.

Apple iPad Windows 7 offered touch controls, but touchscreen tablets really took off with the launch of Apple’s iPad. The iPad transformed mobile computing and paved the way for tablets running a variety of operating systems.

Windows XPWindows XP – the operating system that made Windows so stable that Microsoft is still having to convince companies to part with it today, 13 years after its initial release.

The iMacWindows PCs dominated the 1990s, but Apple introduced the most iconic computer of the decade, the all-in-one iMac. The iMac, launched a year after Steve Jobs returned to Apple and saved the company from financial ruin.

Windows 7Released five years ago, Windows 7 is by far and away the most used computer operating system in the world today. It markedly improved on Windows XP’s reliability and performance.

Windows 8The first version of Windows to have touch controls baked-in, Windows 8 has given birth to dozens of new laptop, hybrid and desktop designs. Windows 8.1, released in 2013, has made several key refinements to the operating system.

From the launch of the first microprocessor, to the operating system that brings touch controls to devices for the first time, we identify the 20 greatest landmarks

in the history of personal computing.

The evolution of personal computing

Find out more about Windows devices

’70s

© 2014

1971

1973

1975

1977

1980

1981

1982

1983

1984

1985

1990

1993

1995

1998

2001

2009

2010

2012

’80s

’10s

’00s

’90s