3. Mainframe Computers

Mainframes are large, powerful computers that can carry out many different tasks for many different people at the same time.

They are slower than a supercomputer but they are far less expensive. They may cost around 4 million pounds to purchase.

Mainframes can execute billions of instructions per second and can process large amounts of data simultaneously.

They are usually connected to a large number of peripherals e.g. printers, terminals, disk drives etc.

They are used by large companies such as:

• Utility companies e.g. gas and electricity suppliers to calculate customer bills.
• Banks - for managing thousands of customers accounts each day
• Insurance companies - for keeping track of policies and claims
• Airlines - for dealing with bookings, tickets, cancellations etc
• Police - for storing and processing all of the data collected each day about crimes

Mainframe computers need to be operated by specialist, trained staff. They are usually kept in an air-conditioned rooms away from the office or factory floor.