Mainframes, networks, and you

Regardless of which elements comprise a particular network, you--the end user--are the ultimate source and destination of the information that flows through it.

In the broadest sense of the word, a network is an interconnected system of people or things. In the fast-paced, lively field of information technology (IT), a network is defined as the hardware and software that enables computers to share files and resources and exchange data. Depending on the size of a business, a network can be as simple as two personal computers on a locally connected network or as complex as the Internet, a worldwide network of millions of computers of various types.

To send or receive data through a network, a company's employees interact through a variety of communication devices, such as telephones, workstations, and computers. Network data can flow through an even greater variety of mechanisms: communication software and hardware, telephone wires, broadband cable, wireless and microwave transmission units, satellite, fiber optics, and so on.

To some extent, the definition of "network" depends upon who is using the network. For example, even though voice and data share the same network, an IT professional hired to support the voice traffic will likely view the network differently than the person assigned to maintain data traffic. The telephony expert or electrical engineer might describe the network as "a group or system of electronic components and connecting circuitry designed to function in a specific manner," while a network designer or architect might explain the network as "a system of lines or channels that cross or interconnect, forming a complex, interconnected group or system."

In this information, we'll try not to be so tedious or evasive. Our definition of "network" encompasses all the usual ideas:

A group of interconnected computers capable of exchanging information
A collection of computers and associated devices connected by communications facilities (hardware and software) that share information
The entity that allows users, applications, and computers in a corporation to exchange data and files for the purpose of transacting business

And, our primary focus will be on how network technology relates to mainframe computers, the workhorses of corporate IT.

To be effective, corporate communications rely on secure links between thousands of end users, applications, and computers of various sizes, including mainframes. Wherever speed and security are essential, mainframes are used as the most critical servers in the network infrastructure.

If you have never pondered the incredible inter-connectedness of the modern world, its computers, and its end users, consider your own experience: you use a complex network when you:

Withdraw money from a bank account through an automated teller machine (ATM)
Submit a payment at the supermarket with a debit or credit card
Purchase a music download over the Internet

Computer networks touch nearly every aspect of everyday life. And, when a large organization needs transaction processing, the odds are that the network is connected to a mainframe.

What is a mainframe? It's a computer that supports dozens of applications and input/output devices to serve tens of thousands of users simultaneously.

What separates the mainframe from other computers is not just its processing capabilities. A mainframe has redundant features and system health awareness capabilities that enable it to deliver 99.999% availability.

Throughout this information, the general term "mainframe" refers to large computers like those in the IBM System z9 and eServer zSeries processor families.