Description of System

A small store uses a very simple stock control system. The system stores the details of all of the products that the store sells. These details are kept in a stock file on a magnetic disk. Each product that the store sells can be identified by a unique product code.

When a customer takes her shopping to the checkout the checkout operator inputs the product code numbers from the items that are being purchased using a bar code reader. If a product code is scanned correctly then the till beeps. If the code is not scanned correctly then there is no beep so the operator knows that the bar code must be rescanned. If the code will not scan a second time then the operator must manually type the product code into the till using a keyboard.

When a code is successfully entered, the checkout looks up the product code in the stock file. From the stock file the name of the product and its price is obtained. This information is printed on the customer's receipt and the total cost of the purchases is calculated.

At the same time the record that the computer keeps of how many units of each product are in stock is amended to show which items have been sold. At the end of the day the checkout will print a list of the items that are running low on stock so that they can be reordered.

Identification of Outputs, Inputs, Processing and Storage Requirements

From this description of the system, it is possible to identify what the outputs, inputs, processing and storage requirements of this system are. They are summarised in this table :

Outputs	Itemised till receipt for each customer.
	Buzzer noise when a product code is scanned correctly.
	List of products which need reordering to be printed at the end of each day.
Inputs	Product code of each product that is sold to be entered using a bar code reader or keyboard.
	List of all of the products that the shop sells to be entered when the system is first set up and amended later as necessary.
Processing	As products are sold look up product codes in stock file. Print item names and prices on receipt and add up totals.
	Monitor how many units of each product are in stock by reducing the stock level of an item when it is sold.
Storage	A stock file will be held on magnetic disk. For each product the shop stocks this file must contain : The product's code. The product's name. The product's price. How many units of the product the shop has in stock.

Diagramatic Model of System

This system flowchart shows the structure of this information system in diagram form :

GCSE ICT Companion 04 - (C) P Meakin 2004