A computer that can fit in a room, on a desk, on a lap, in your hands, or even in your pocket.
They are mostly used in the early 21st century to access a great bank of information stored on a network of networks called the Internet. All of human knowledge is available at any time, and most people use the internet for looking at pictures of cats.
The room computers we call 'servers', and, much like the radio/television stations of the 1950s, these are where the information and media is stored. These are mostly boxes, from 2 foot high to 6 foot high, which can be accessed from a different location.
Desk computers are called 'Personal Computers'. These were used mostly in the 80s and 90s. Consists of a box, usually a couple of foot tall, and a screen like a television, though later these became flat. Input is mostly through a keyboard, with keys arranged like a typewriter, and a movable puck with a couple of buttons called a 'mouse'. This moves an arrow on the screen, to perform operations.
Lap computers are called 'Laptops', 'Notebooks', 'Netbooks' or 'Ultrabooks'. Similar to the desk computers, except it folds and opens like a book, with a flat screen. The mouse is dispensed with, a small pad through which you move the arrow with your finger is used instead.
Hand computers are called 'Tablets', like a flat screen, you use your fingers to touch items directly on the screen to perform operations.
Pocket computers, called 'smartphones' which evolved from mobile versions of the telephone. Can make phone calls, but can also browse the Internet. Similar to tablets, with the flat touchable screen to perform operations.
The desk PC, laptops, tablets, smartphones can browse the Internet, listening to music, watching videos, connecting to networks without the use of wires - similar to radio reception but on a local level.
