A computer monitor is vastly different from a television tube in the quality and resolution of the picture. The standard for television resolution was developed in the 1950's. The computer monitor has been changing constantly since it was introduced as a single color monochrome unit. A current monitor can display millions of colors and can display resolution into the thousands of pixels. The standard quality for a current monitor is a resolution of 800X600 or higher and a dot pitch of 0.28 or less.
Dot pitch is the distance between individual pixel elements of the screen that produce the picture.
A monitor is usually separate from the rest of the computer, and it is attached by a cable to the computer. As PC's have grown larger and more sophisticated their cases have become larger. PC's are no longer always desktop units. There are tower cases designed to sit on the floor as well as cases that house everything including the monitor. The keyboard is an input device consisting of a set of keys in a standard layout.