Computer hardware

Computer hardware encompasses the tangible components of a computing system, such as the central processing unit (CPU), random-access memory (RAM), motherboard, data storage devices, graphics and sound cards, and the computer case, along with peripherals like monitors, keyboards, mice, and speakers. It operates under the direction of software—written instructions that can be stored and executed—and together they form a functional computing system. The term "hardware" reflects its rigid, unchangeable physical nature, contrasting with the easily modifiable "software."

The history of hardware stretches back to the seventeenth century. In 1642, Blaise Pascal created the Pascaline, a gear-based adding and subtracting machine. Gottfried Leibniz later invented the stepped reckoner in 1676, capable of multiplication and division, though design flaws limited its practicality; similar Leibniz wheel mechanisms persisted into the 1970s. In the nineteenth century, Charles Babbage designed the difference engine for calculating polynomials and a general-purpose computer that was never built, but its concepts—punch cards, memory, an arithmetic unit, and a primitive programming language—influenced early computers.

Alan Turing’s 1936 universal Turing machine modeled any computer’s operations via stored programs, linking hardware and software. George Boole’s mid-nineteenth-century Boolean algebra became the foundation for modern integrated circuit logic. By 1945, relays and vacuum tubes enabled the first computers, such as George Stibitz’s relay machines and Howard Aiken’s MARK I. John von Neumann’s 1945 architecture—centralized memory storing both data and programs, a CPU with memory priority, and I/O units—became the template for most modern computers, though its single bus created the von Neumann bottleneck when fetching data and programs simultaneously.

Computer architecture

Computer architecture balances cost, speed, availability, and energy efficiency, requiring knowledge from compilers to integrated circuit design. Cost pressures have driven manufacturers to lower prices and reduce profit margins, while improved manufacturing has steadily dropped component costs. The most common instruction set architecture (ISA) derives from von Neumann’s 1945 design.