Information Technology · Ch 1 — Basics of Information Technology
The Computer System — Hardware and Software
The Computer System — Hardware and Software
What Is a Computer?
A computer is an electronic device that accepts data as input, processes it according to a set of instructions (a program), produces useful output, and can store data and instructions for later use. Every computer, from a large server to a smartphone, works on the same basic cycle: Input → Processing → Output, supported by Storage. This is often called the IPO (Input-Process-Output) cycle.
A complete computer system is made up of two inseparable parts: hardware and software. Neither is useful without the other — hardware without software is like a body without instructions, and software without hardware has nothing to run on.
Hardware
Hardware refers to the physical, tangible parts of a computer — the components you can see and touch. Hardware is grouped by the function it performs in the IPO cycle:
- Input devices — take data and instructions into the computer (e.g. keyboard, mouse, scanner).
- The Central Processing Unit (CPU) — often called the "brain" of the computer, it carries out the actual processing. The CPU has two main parts: the Arithmetic and Logic Unit (ALU), which performs calculations and comparisons, and the Control Unit (CU), which directs and coordinates all the computer's operations. Modern CPUs are built onto a single chip called a microprocessor.
- Memory (primary storage) — holds data and instructions that the CPU is currently working on (e.g. RAM).
- Output devices — present the processed results to the user (e.g. monitor, printer).
- Storage devices (secondary storage) — store data and programs permanently for future use (e.g. hard disk, pen drive).
Software
Software refers to the set of programs, instructions, and procedures that tell the hardware what to do. Software is intangible — it cannot be physically touched, only stored and run. Without software, a computer's hardware cannot perform any task. Software is broadly divided into two categories, studied in detail in a later section:
- System software — programs that run and manage the computer itself (chiefly the operating system).
- Application software — programs that help a user perform specific tasks (word processors, spreadsheets, accounting software, browsers).
Hardware vs Software
| Basis | Hardware | Software |
|---|---|---|
| Nature | Physical, tangible parts | Programs and instructions; intangible |
An electronic device that accepts data as input, processes it according to stored instructions, produces useful output, and can st …
The physical, tangible parts of a computer that can be seen and touched, such as the CPU, keyboard, moni …
The set of programs and instructions that tell the hardware what to do; it is intangible and cannot be …
The 'brain' of the computer that carries out processing; it contains the Arithmetic and Logic Unit (ALU) and th …