Q.What are the four main components of a computer system? Briefly explain the role of each in an accounting context.

A computer used for accounting work is organised around four cooperating parts, each with its own distinct job in the input-process-output cycle.

Input devices (keyboard, mouse, scanner) let accounting data enter the system; the CPU processes that data according to the software's instructions; storage keeps the records permanently; and output devices (monitor, printer) present the results — a ledger view, a printed report — back to the user.

A computer system used for accounting work is built from four cooperating parts, each responsible for one stage of handling data.

1. Input devices. These let raw data and commands enter the computer — a keyboard for typing a voucher's details, a mouse for choosing a menu option, a scanner for reading a printed bill. In an accounts office, this is the point where a real-world transaction first becomes data inside the system.

2. Central Processing Unit (CPU). Often called the computer's "brain," the CPU carries out the actual arithmetic and logical work that the accounting software instructs it to do — adding a column of figures, comparing an amount against a limit, deciding which ledger account an entry affects. Every calculation an accounting package performs happens here.

3. Storage. A hard disk or solid-state drive holds data permanently, so vouchers, ledgers and reports built up over months or years remain available even when the computer is switched off. Working memory (RAM) holds only what is actively being used at that moment.

4. Output devices. A monitor displays processed results on screen — an up-to-date ledger, a trial balance — while a printer produces a paper copy of an invoice, statement or set of final accounts when one is needed.

These four parts always work together in the same repeating cycle: data goes in through input devices, the CPU processes it, storage keeps a permanent record, and output devices present the result. Every later concept in a computerised accounting system — from a simple voucher entry to a full accounting information system — builds on this same basic cycle.