Types of Hardware

CSS Computer Science (Optional) — Paper-I, Section-A, Topic I, p.20-22. Covers: Types of Hardware.

Definition

Computer Hardware: any physical, tangible part of a computer system — components that can be seen and touched (contrasted with software, which is a set of intangible instructions stored/run on that hardware).

Category	Role	Examples
Input	Feeds data/commands into the system	Keyboard, mouse, scanner
Output	Presents processed results to the user	Monitor, printer, speaker
Processing	Executes instructions, coordinates the system	CPU, motherboard chipset
Storage	Holds data/programs, temporarily or permanently	RAM, ROM, HDD, SSD
Communication	Exchanges data between computers/networks	Modem, NIC, router

Input hardware: keyboard, mouse, scanner, microphone, etc. — full detail on the Input Devices page.
Output hardware: monitor, printer, speaker, plotter, etc. — full detail on the Output Devices page.
Processing hardware: CPU + motherboard chipset — detailed below.
Storage hardware: HDD, SSD, RAM, ROM — full detail on the Storage Media page and Components of a Computer System page.
Communication hardware: modem, NIC, router — detailed below.

By location:
- Internal hardware: inside the case — CPU, RAM, motherboard, internal HDD/SSD, power supply.
- Peripheral/External hardware: connected from outside — keyboard, mouse, monitor, printer, external drives.
By necessity:
- Essential/Core hardware: required for the system to function at all — CPU, RAM, motherboard, power supply, primary storage.
- Peripheral/Optional hardware: adds functionality but isn't required to boot/run — printer, scanner, speakers, webcam.
Exam angle: examiners may ask you to classify a given list of devices by any of these axes (functional role, internal/peripheral, essential/optional) — state which axis you're using explicitly in your answer.

CPU (Central Processing Unit)
- Definition: the "brain" of the computer — fetches, decodes, and executes instructions.
- Key parts: ALU (Arithmetic Logic Unit — performs calculations/logic), CU (Control Unit — directs the flow of operations), Registers (tiny, ultra-fast storage for data currently in use).
- Related concepts: Clock speed (GHz) — instruction cycles per second; Cores — independent processing units on one chip, enabling parallel execution.
Motherboard (Chipset)
- Definition: the main circuit board connecting all hardware components together.
- Key parts: CPU socket, RAM slots, expansion slots (e.g., PCIe for graphics/sound cards), buses (data/address/control pathways).
- Role: coordinates communication between the CPU, memory, storage, and peripherals.

Modem (Modulator-Demodulator)
- Definition: converts digital data from a computer into analog signals for transmission, and back again.
- Use: essential for older telephone-line Internet; broadband modems now handle digital cable/fiber signals directly.
Network Interface Card (NIC)
- Definition: hardware that physically connects a computer to a network — an internal expansion card, a chipset built into the motherboard, or a USB adapter.
- Variants: wired (Ethernet) — connects via cable/RJ-45 port; wireless — connects via Wi-Fi through an antenna.
- Key fact: every NIC carries a unique hardware MAC address identifying it on a local network; without a NIC, a computer has no physical means of joining a network.