Optical storage, read-only CD-ROM followed by writeable CD and later read-only or writeable DVD and Blu-ray players, became common in laptops early in the 2000s.
Since the introduction of portable computers during late 1970s, their form has changed significantly, spawning a variety of visually and technologically differing subclasses.
A laptop, often called a notebook or "notebook computer", is a small, portable personal computer with a "clamshell" form factor, an alphanumeric keyboard on the lower part of the "clamshell" and a thin LCD or LED computer screen on the upper part, which is opened up to use the computer.
Laptops are folded shut for transportation, and thus are suitable for mobile use.
The Sharp PC-5000, From 1983 onward, several new input techniques were developed and included in laptops, including the touchpad (Gavilan SC, 1983), the pointing stick (IBM Think Pad 700, 1992), and handwriting recognition (Linus Write-Top, 1987).
Examples of specialized models of laptops include rugged notebooks for use in construction or military applications, as well as low production cost laptops such as those from the One Laptop per Child (OLPC) organization, which incorporate features like solar charging and semi-flexible components not found on most laptop computers.
Portable computers, which later developed into modern laptops, were originally considered to be a small niche market, mostly for specialized field applications, such as in the military, for accountants, or for traveling sales representatives.
Traditional laptops are the most common form of laptops, although Chromebooks, Ultrabooks, convertibles and 2-in-1s (described below) are becoming more common, with similar performance being achieved in their more portable or affordable forms.
A subnotebook or an ultraportable, is a laptop designed and marketed with an emphasis on portability (small size, low weight, and often longer battery life).