What is a mainframe computer?

by Steve Macrie steve@serviceteam.co.uk

Mainframes are big computers mostly used for running multifaceted applications involving data processing in huge amounts. The name arose in connection to the arrival of smaller computers which were branded as minicomputers, primarily to make a distinction between them.

Capabilities and Usage

Mainframe computers are primarily used as servers which are capable of storing large amounta of data, sustaining vast number of processes and input/output devices to provide multiple users with the information they need all at the same time. They are able to achieve this by properly allocating their resources. These machines can run nonstop for years with repairs and maintenance done without shutting them down.

Most mainframes nowadays have the capability to host a number of operating systems allowing them to function like multiple computers or "virtual machines". In this case, one mainframe can replace any number of personal computers thereby decreasing related costs and giving far greater scalability and consistency. The scalability is attained by reallocating the hardware resources among the virtual machines as required, and the consistency is enhanced because the hardware redundancy has been removed. This can also be done with PCs but it's a little more complex. For instance, adding a disk drive into a PC requires it to be powered down, and not to mention their hardware limitations. A mainframe can supply the much needed power for which they are known for, and the adaptability of PC networks.

Mainframe Background

The birth of the mainframe took place in the 1950s with the arrival of the IBM 700/7000 series. From that time there has been a succession of mainframe models from IBM and other manufacturers alike. But like any other fresh innovation, the mainframe has it's share of drawbacks - it's main oneis it's high price.

As the computer technology progressed, companies found that microcomputer based servers could be utilized at a far lower cost than a mainframe. As a result, workstations that used to interact with mainframe systems were steadily substituted with personal computers. The demand went on a steady decline and mainframe systems were just confined to institutions requiring enormous data processing capabilities. Industry analysts thought the mainframe was a vanishing market because mainframes were being steadily replaced by cheaper but powerful personal computer systems.

However, in the 1990s big companies found a new life for their mainframes – the World Wide Web came to the rescue. They realized that a mainframe can be utilized as a web server which can take on the equivalent of hundreds of inter-connected personal computers. And this time the cost is much lower in terms of power usage and management. The downtrend began to reverse.

Mainframe access is gradually increasing and another reason for it was the arrival of the Linux operating system on the scene. Linux is one of the few operating systems that can run on mainframes either directly or in a virtual machine. This permitted the mainframes to benefit from the work of various PC developers.

At Present

The mainframe keeps on growing in terms of it's capacity and the scale of its installations. Perceptions are slowly changing as shown by their inclusion into the world of internet. The mainframe computer has proven its ability to deliver an increasing array of information technology services at a reasonable cost.

Nope. We don't repair mainframes. We're not clever enough. But we do provide a Computer fault diagnosis and repair service.

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