Notebook, notebook computer, laptop, and laptop computer are different terms for a small computer, which is mobile, and weighing about 1 to 6 kg or 2.2 to 18 pounds, depending upon the model. In 1979-1980, Bill Moggridge of GRiD Systems Corp. designed one of the first laptops and named it as the GRiD Compass 1101. It featured the clamshell design where the flat display folded shut on the keyboard. In May 1983, Gavilan Computer Corp. introduced and first marketed as a laptop, known as Gavilan SC. About this same time, Sharp Corp.Ltd., announced their laptop Sharp PC-5000.

In 1989, Compaq introduced Compaq LTE, which was a laptop of a smaller size, about the size of an A4 paper notebook, and it popularly came to be known as a notebook computer or notebook. Thereafter the terms laptop and notebook began to be used interchangeably. Nevertheless, the terms, notebook and laptop are incorrect terms, as due to the heat, many laptops cannot be placed on top of the lap, and most notebooks are not the size of an A4 paper notebook. However, what manufacturers usually call as a notebook, end-users prefer to call it as a laptop; hence both the terms are used.

According to the functions and the models of notebooks, they are generally classified as: Ultraportables (screen is diagonally less than 12 inches, weight is 1.7 kg or less); thin-and lights (screen is diagonally from 12 to 14 inches, weight is from 1.8 to 2.8 kg); medium-sized laptops (screen is diagonally from 14 to 15.4 inches, weight is from 3 to 3.5 kg); and desktop replacement computers (screen is diagonally from 17 to 20 inches, weight is 4 to 6 kg).

The concept of laptop was to make a device that could use the same software of a desktop computer, but much smaller in size to enable mobility and support mobile computing (ability to use the computer while in transit). Thus, further innovations have introduced transportables (which can be moved from one place to another without supporting mobile computing); tablets (which feature touchscreens and support mobile computing); ultra mobile PCs (which are very small and compact tablet PCs); internet tablets (which support internet and mobile computing); personal digital assistants (PDAs), which are pocket-sized and support mobile computing; handheld computers, which represent expensive tablets or PDAs; and smartphone, which is a PDA or a handheld computer with cellphone integration. Over the development phases, these classifications got blurry at times, and many machines fused functionalities of other categories.

Notebooks can be used for various purposes. Commercial purposes like attending phone calls, receiving and sending emails and faxes, typing out letters and printing them, making presentations with pie and bar charts, and taking data from one place to another can be achieved by any standard notebook. However, high fliers prefer thin-and-light notebooks and for regular office work, ultraportable notebooks are preferred. Both are wireless notebooks so they can be remotely accessed. Scientific purposes are best suited with a notebook that features fast computing speed, good 2D and 3D graphics display, and a large memory, like desktop replacement notebook, and a thin-and-light notebook. Artistic purposes require animation, 2D and 3D drawings, interior & exterior designing, arranging music compositions, post-production audio-video work, etc., which can be fulfilled by desktop replacements, gaming notebooks, and mainstream notebooks.

Educational institutions normally do not prefer notebooks due to its high chance of being stolen. Additionally, they prefer that their assets do not move around within the premises in the hands of students who may be careless. However, to keep up with the times, and to be considered as techno-savvy, they do invest in notebooks. The types of notebooks best suited for educational purposes are mainstream notebooks, and desktop replacements. Students need a notebook to do projects, prepare study notes, and to play some games in their spare time. They need to take the notebook wherever they go, hence, size and weight are major considerations. The type of notebook that fulfills student needs is a thin-and-light notebook with locking facility so that they can lock it with their backpack. Most students report late submission of projects due to their notebooks being stolen.

So no matter what the purpose one might have for using a notebook, it seems that mobility will always seem to be the main reason for such a product purchase. Nowadays with so many models being offered with affordable prices, it seems that notebooks will always be a product in demand. After all it is one of the best selling computer hardware for quite some time. And that says it all.