Most computer makers have conceived their lap top computers to work with a keyboard and mouse, and they will also have a pad and or joystick that can be used to move around the cursor on the screen. Notebooks come in three basic styles differing in size. An extremely small lap top will generally weigh less than 1.7 kilograms, while a lightweight slim version will weigh up to 2.8 kilograms, and a medium sized laptop will weigh up to 3.5 kilograms. The idea for the laptop existed prior to the invention of the personal computer, and was originally developed in the 1970’s. The first to market was the Osborne 1, which was released in 1981. Get the latest Notebook Test