Palm top computer by Psion, Model Psion Series 5, 1997. The increasing miniaturisation of computer technology and the desire for portable computers which could be used while out of the office led to the development of laptop computers. The palmtop computer, such as this example manufactured by Psion Computers plc, England, took the process a stage further. Rather than using a mouse and pointer to click on the icons on the desktop, palmtop computers use a stylus which is physically tapped on the screen. Dimensions: 25mm x 180mm x 100mm.