Computer hard ware is the collection of phisically elements that constitutes a computer system.
Computer hardware is the physical parts or components of a computer,such as the monitor,mouse,keyboard, computer data storage,hard disk drive,graphic cards,sound cards,memory,motherboard and so on,all of which are physical objects that are tangible.In contrast,software is instructions that can be stored and run by hardware.
The term hardware covers all of those parts of a computer that are tangible objects. Circuits, displays, power supplies, cables, keyboards, printers and mice are all hardware.
Calculators : Pascal's calculator, Arithmometer, Difference engine, Quevedo's analytical machines
Programmable devices: Jacquard loom, Analytical engine, IBM ASCC/Harvard Mark I, Harvard Mark II, IBM SSEC,Z1, Z2, Z3
Calculators : Atanasoff-Berry Computer, IBM 604, UNIVAC 60, UNIVAC 120
Programmable devices : Colossus, ENIAC, Manchester Small-Scale Experimental Machine, EDSAC, Manchester Mark 1, Ferranti Pegasus, Ferranti Mercury, CSIRAC, EDVAC, UNIVAC I.
Mainframes : IBM 7090, IBM 7080, IBM System/360, BUNCH
Minicomputer : HP 2116A, IBM System/32, IBM System/36, LINC, PDP-8, PDP-11
4-bit microcomputer : Intel 4004, Intel 4040
8-bit microcomputer : Intel 8008, Intel 8080, Motorola 6800, Motorola 6809, MOS Technology
16-bit microcomputer : Intel 8088, Zilog Z8000, WDC 65816/65802
32-bit microcomputer : Intel 80386, Pentium, Motorola 68000, ARM
64-bit microcomputer : Alpha, MIPS, PA-RISC, PowerPC, SPARC, x86-64, ARMv8-A
Embedded computer : Intel 8048, Intel 8051
Personal computer : Desktop computer, Home computer, Laptop computer, Personal digital assistant (PDA),Portable computer, Tablet PC, Wearable computer
Theoretical/experimental : Quantum computer, Chemical computer, DNA computing, Optical computer, Spintronics based computer
Input : Mouse, keyboard, joystick, image scanner, webcam, graphics tablet, microphone
Output : Monitor, printer, loudspeaker
Both : Floppy disk drive, hard disk drive, optical disc drive, teleprinter
Computer busesv : Short range RS-232, SCSI, PCI, USB
Long range : (computer networking) Ethernet, ATM, FDDI