16.3 Networked computers in the supermarket checkout system
All these processes are very helpful for the purposes of dealing with an individual customer's purchases. However, when computers are linked in a network, many new uses are possible.
Now, I am going to draw a different system boundary. The components of this supermarket checkout system are the checkout terminal, the network and the database server. A database server is used to make the data in databases available to other computers on the network, and therefore to users. You met a specialised form of database server in Section 14.2: the FirstClass server. In the following sections, I'll focus on the network first and then look at the database server.
The system map for the supermarket checkout system is shown in Figure 14. You might be wondering about the users of the system: the customer and the checkout operator. For the time being, we are focusing on the computers and network, rather than thinking about the end users, so in this system map they are not shown.
