Therefore, the data on a hard disk cannot usually be carried from one computer to another. For this reason, hard disks are sometimes called Winchesters. A CD-ROM is a type of hard disk that uses laser beams rather than magnets to read and write bits of information on the surface of the disk. CD-ROMs, unlike most hard drive platters, are removable. These advances made it possible to place the entire CPU of a computer on a single chip.
All computers share the same basic architecture.
The CPU of a microcomputer performs all the arithmetic, logic, and data handling functions of the microcomputer. The most common input device used with microcomputers is the keyboard. Output can be directed to a video monitor, printer, or disk drive. Composite monitors are capable of displaying text and low resolution graphics. TTL and RGB monitors can display high resolution graphics.