The laptop notebook computer is a mobile computer that is small enough to be carted and kept on the lap while working. It does not weigh more than 1 to 6 kg. It is much smaller than its elder sibling - the desktop computer. A laptop does the same functions as the desktop one and therefore the parts are the same but of mini size. Instead of a mouse a touchpad does the tracking but if required a mouse can be attached. Internet tablets are used for the vital interspace link.

The laptops have both good and bad points. Due to technical and economic hurdles the unit cannot be upgraded easily. Regarding health matters the laptop is blamed for low sperm count as it is kept continuously on the scrotum that causes the heat to rise to undesirable levels in this region of the body. To avoid it the mobile unit can be kept on the desk and does not necessarily have to be kept on the lap all the time.

Another obvious problem is that laptops can easily be stolen. Laptops are relatively slow and have less sound and graphics capability. Laptops are much more costly than desktops but of late the gap is closing. However Laptops consume less power. The performance is more or less the same as the desktop models and new generation models are becoming more efficient and user friendly.

How can such a small package hold such varied capabilities?

Laptops and desktops run on the same principles but the difference is how the components are fitted and fixed. In a desktop there are motherboard, video card, hard drive etc. The monitor, keyboard and other incidental items are connected without wires or with cables but there is sufficient space for extra cards, cables while allowing for flow of air. In a laptop the screen and keyboard rests on the side of the box. The design of the laptop is small and flat wherein all the pieces fit in snugly. Thus the space is compact allowing for conservation of power and less production of heat.

The CPU is the brain of the computer and a fan and heat sink system with plates and channels are required to cool it. But a laptop runs on a lower voltage resulting in less speed. Instead of pins and socket as in a desktop, in a laptop balls are used. However it means that the processor cannot be removed separately. The batteries of laptops that run fast suffer from being frequently run down. The Apple G4 processor tries to neutralize this defect.

Laptops use mini sized fans, heat spreaders and heat sinks. Some use liquid coolants to keep down the temperature. The CPU`s of the laptops are placed near the edge of the box allowing for hot air to be released without flowing over other components. A laptop also has a hard disk drive wherein is stored the operating system, data and application files.

The mechanism of memory differs from one laptop model to another. Usually smaller memory modules are used to economize on space. Both run on electricity but a laptop can also function on batteries.

Every invention begins with a dream. In 1970 Alan Kay of Xerox had such a vision of a portable computer approximately the size of a notebook. He never went much ahead with the idea but set the balls rolling. In 1979 the first working portable computer was made by William Moggridge of Grid Systems. Others like Apple soon jumped in to complete the success story.