Think about what actually happens when a shopkeeper records a sale on a computer instead of in a register. In the register, the "system" was just paper and a pen and the shopkeeper's hand. On a computer, that one act of recording a sale quietly pulls in several different things at once: a machine to type on, a program that knows what a "sale" means and where to put it, a person who understands accounting well enough to enter it correctly, the actual figures being entered, and a set of rules deciding which account gets debited and which credited. Remove any one of these and the sale never becomes a proper accounting entry. That is the whole idea behind the components of a computerised accounting system — it is not one thing but a working combination of parts, each useless without the others.
The five components
A computerised accounting system (CAS) is the entire arrangement — not just the software — by which accounting data is captured, processed and turned into financial information. It rests on five components:
Hardware. The physical equipment: computers, servers, keyboards, printers, scanners, storage devices, networking gear. This is the body of the system — it stores and processes data, but on its own it understands nothing about debits or credits.
Software. The set of programs that actually perform accounting. This includes the operating system and, crucially, the accounting application (and utilities like spreadsheets or a database). The software encodes the accounting logic — it knows that every transaction must keep the books balanced, how to post to ledgers, and how to generate a trial balance or balance sheet.
People. The human beings who run the system: the accountant, the data-entry operator, the system administrator, the auditor. A CAS is only as good as the people operating it. An untrained operator can wreck even excellent software by entering wrong data or misclassifying a transaction.
Data. The raw accounting facts fed into the system — the transactions, amounts, dates, account heads, and the resulting records (ledgers, journals). Data is the fuel; without accurate input, the output is worthless. This is the "garbage in, garbage out" principle.
Procedures. The rules and methods that tie everything together — the accounting policies, the sequence of steps for recording and verifying transactions, internal controls, backup routines, and authorisation rules. Procedures are the glue: they decide who may enter what, how errors are corrected, and how the books are closed.
A CAS is the combination of all five — hardware, software, people, data and procedures. It is not merely the accounting software. Reliability comes from the components working together, not from any one of them alone.
Why the "combination" framing matters
It is tempting to think of a CAS as "the Tally package" or "the accounting software." That is a mistake, and it is the single most common one students make. Software is only one of five parts. A firm can buy the best accounting software in the market and still produce unreliable financial statements if its operators are untrained, its data is sloppy, or its procedures allow anyone to alter entries at will. …