Although the palmtop computer, also known as the PDA(personal digital assistant) has been with us since the early 80s, it is only in the last few years that they have become a popular mass market product. The reason for this has been the convergence of mobile phone and computer technology, exemplified by products such as the Blackberry and the Nokia N97, which are basically small, internet capable multimedia PCs that can also be used as mobile phones.

The first true palmtop computer, released in 1983, was the Casio PF3000, which was able to replicate all the functions of a paper based Filofax or Rolodex in one portable, battery powered package. Throughout the eighties and nineties, a number of similar items built by firms such as GO and Psion were marketed as digital personal organisers.

The term PDA was first used by Apple to describe their new digital organiser, the Newton, in 1992. The marketing hype described it as The Computer of the Future, which in some ways it was, as it did away with the keyboard to make way for a large touch sensitive screen and a small plastic stylus.

The public were initially blown away by the concept, but in practice, the machine was a good deal less useful than it seemed in the demonstrations. The handwriting recognition was not in the slightest bit reliable, and with no alternate input device, this made the machine less than useless for most of the people who bought it. More PDAs arrived with a similar concept as the decade wore on, the most successful of which was the Palm Pilot, which used a system of designated strokes to represent letters rather than claiming to be able to read handwriting.

However, when some bright spark decided to combine a cellphone with a PDA, a monster was born. That monster was the Nokia 9000 Communicator, which came out in 1996 and instantly struck a chord with the occupants of business class on trains and planes, becoming the biggest selling PDA ever made up to that point.

Most modern PDAs feature a combination of input devices, including touch sensitive screens, tracker balls, and small QWERTY keyboards. Other common features include a memory card slot, the ability to connect wirelessly to the internet and to other PDAs via technologies such as Bluetooth and WiFi, and the ability to download software applications to increase the functionality of the machine.

An important feature of the modern PDA is the ability to connect it to a computer and share data such as email addresses, documents, and diary entries, at the touch of a button, ensuring that you have at least two copies of this information and that you don't have to enter anything twice.

Modern PDAs can do virtually everything a PC can do, such as run office software, surf the web, play video and audio files and act as satellite navigation systems, and new applications are being developed all the time. Not bad for a technology that is less than thirty years old!