Basic computer (system) architecture refers to the structure of a computer system and comprises its hardware, firmware, and software. The architecture of most computers constructed in the past two decades has settled on a model consisting of one or more central processing units (CPUs), memory, and peripheral devices, all connected with a bus (or more than one). Most computers have one or more types of connectors that permit the attachment of storage devices, output devices (such as printers or plotters), human interface devices (such as a keyboard, monitor, and mouse), and communications to local area networks (LANs, WiFi, or Bluetooth). Most computers have a primary software program called its operating system, which facilitates most general-purpose or specific uses for the computer. The operating system allows application programs to use the computer’s hardware to perform tasks. This architecture is in use in the very smallest computers (even hand-held computers, such as Apple’s iPhone), laptop computers, server computers, and mainframe computers and supercomputers.
Hardware consists of the physical components in computer architecture. This broad definition of hardware can include keyboards, monitors, ...