It seems that in today's world nothing can be done without a computer, but upon a closer look, you will find that it is the hardware components and input and output devices that make a computer useful. It may also mean the physical components of a computer system, in the form of computer hardware. In Information technology, hardware is the physical aspect of computers, telecommunications, and other devices. Hardware includes not only the computer proper but also the cables, connectors, power supply units, and peripheral devices such as the keyboard, mouse, audio speakers, and printer. Computer operation requires both hardware and software. Computers come in different forms, but most of them have a common architecture. All computers have a CPU and have some kind of data base which lets them get inputs or output things to the environment. All computers have some form of memory. A computer has several main parts. When a computer is compared to a human body, the CPU (central processing unit) is like a brain; it does most of the 'thinking' and tells the rest of the computer how to work. The CPU is on the Motherboard, which is like the skeleton, which provides the basis for other parts, and carries the nerves that connect them to each other and the CPU. The motherboard is connected to supply power, and thus provides electricity to the entire computer. The various drives include CD drive, floppy drive, and on many newer computers, has a USB drive that which acts like eyes, ears, and fingers, and allow the computer to read different types of storage. Thus, the hard drive is like a human's memory, and keeps track of all the data stored on the computer.