The main keyboard encompassed the bulk of the keys, then a keypad to the right, separated by an array of navigation keys which included arrow keys, while along the top ran the function keys.

Perhaps considered humdrum today, that early design included some keys that were almost left off.

The Escape key, for example, would not have existed if not for the campaign of Bob Bemer, who argued that an escape character was needed to mark an escape sequence in computer code, and as such a special key was needed.

In simple terms, an escape sequence marks the end or transition in a piece of code. Mr Bemer co-founded the ASCII character set and is also credited for giving us the backslash character.

The thing to remember about these early keyboards is they were designed for programmers, not the home user.

The personal computer had yet to be born, and word processing was unheard of, let alone Web browsing.

Fast forward to the 21st century and any new keyboard is as likely to sport a www or e-mail key as it is a scroll lock or break key.

Cynics may consider this new plethora of keys a little over the top, but manufacturers say they are becoming increasingly necessary.

Susan Chen, a sales manager at keyboard manufacturer Ortek, which makes keyboards that include my computer and log off keys, said: 'It's a big trend. Everybody wants more convenience and so more functions in the keyboard.'

Despite the PC being more than 20 years old, and Web surfing around a decade, all these extra keys started breeding only in the past few years.

Starting from just a few Web browsing hot keys, keyboards now sport up to 50 additional keys, many including volume control knobs and scroll wheels. The reason is as much about marketing as it is functionality, with retail prices for keyboards having fallen to under US$10, giving little room for price competition.

Brian Huang, sales manager for Boss Wave Enterprises, which makes mouses and keyboards, said: 'They collect all the normal functions together and then give the user even more.

'Users want more functions in their input device. If you have two in front of you, then you will choose the one with more features.'

He said the more features a keyboard had were strong selling points.

From an aesthetic point of view, keyboard makers are warned to be knowledgeable in their design choices.

Wei Kong, director of industrial design at design consulting firm Titoma, said if functionality was added as a marketing ploy, then extra keys might prove to be cumbersome.

From a production standpoint, the extra keys add little more to the cost, with a high-end keyboard costing just 20 per cent more to manufacture than a simple keyboard, but the retail price can double.

Mr Huang said: 'Within two years, the price will be about the same and all of these functions will be standard.'

But Mr Wei said while the home user might be willing to spend more on a deluxe keyboard for the family, bulk buyers were more price-sensitive and might baulk at the feature-price trade-off.

By the same token manufacturers needed to understand 'if you go cheaper, they will feel cheaper', he said.

All these extra keys leave little left for designers to add, but manufacturers have a few more tricks up their sleeves to make future models stand out.

Expect to see a few USB and Firewire ports in upcoming designs, as well as memory card readers.

KEYED UP

Esc key: Bob Bemer invented this key in 1959 to allow an escape sequence to be easily inserted into computer code.

Backspace: In the old typewriters, the backspace merely took the register back one character from which the typist could mark a mistake with X before moving on. Newer typewriters featuring correction ribbons added the erase function to this key. On the computer keyboard, backspace means erasing to the left.

Scroll Lock: Barely needed since the invention of the scroll bar, themouse and then the mouse scroll wheel, it nevertheless holds onto its coveted place on the keyboard.

E-mail and Search keys: These keys were among the first introduced to the modern 'internet' keyboard, and take the keyboard-PC relationship to a new level. Now a keyboard no longer just enters data, but actually starts programs and initiates applications.

Windows key: Microsoft has managed to get its logo onto millions of keyboards worldwide thanks to this ingenuous inclusion. It merely brings up a pop-up menu, the default being the start menu on the

Windows taskbar.

Delete: An addition to the computer keyboard, Delete differs from Backspace in that it deletes to the right.

Enter: On typewriters, this key was originally much larger, and was called Return because it returned the paper back to the start. In later versions of the keyboard, the key has become smaller to make

room for other keys and its name has been changed to represent the computing function 'Enter'.