Unit 1. computer system

Overview of the Computer System

The Parts of a Computer System
A computer is an electronic device used to process data, converting it into information that is useful to people. A complete computer system includes hardware, software, data, and people. Hardware consists of electronic devices, the parts you can see. Software, also known as programs, consists of organized sets of instructions for controlling the computer. Data consists of text, numbers, sounds, and images that the computer can manipulate.

Looking Inside the Machine
The hardware, or physical components, of a computer consists of a processor, memory, input and output (I/O) devices, and storage. The processing function is divided between the processor and memory. The processor, or CPU, is the brain of the machine. Memory holds data and program instructions as the CPU works with them. The units of measure for memory are the byte, kilobyte, megabyte, gigabyte, and terabyte. The role of input devices is to provide data from the user or another source. The most common input devices are a keyboard and a mouse. The function of output devices is to present processed data to the user or to another computer. The most common output devices are a monitor and a printer. Communications devices, such as modems and network interface cards, perform both input and output functions, allowing computers to share information. Storage devices hold data not currently being used by the CPU. The most common storage devices are a floppy disk, a compact disk, a Digital Video Disk.

Software: Bringing the Machine to Life
Programs are electronic instructions that tell the computer how to accomplish certain tasks. When a computer is using a particular program, it is said to be running or executing the program. The operating system tells the computer how to interact with the user and how to use the hardware devices attached to the computer. Application software tells the computer how to accomplish tasks the user requires. Some important kinds of application software are word processing programs, spreadsheets, database management software, presentation programs, graphics programs, multimedia applications, entertainment and education software, Web design tools and Web browsers, Internet applications, utilities, and networking and communications software.