Mainframe computers, referred to as big iron in some circles, are used in areas that cannot be handled by a mini-computer. The mainframe’s architecture allows for high volumes of users and transactions. It has a large memory capacity and can process a high volume of data at a very rapid rate. This makes it ideal for processing large amounts of information and storing massive databases.
It is also capable of running multiple operating systems simultaneously on a single machine. Typical combinations include z/OS, z/VSE, Linux for System z, and z/TPF. These systems are highly stable and reliable, with mean time between failure measured in decades. The scalability of mainframes means that businesses can add or remove capacity without interrupting operations.
Mainframes were once found in almost every business, but today they are used primarily by large companies for mission-critical applications. These include censuses, industry and consumer analytics, enterprise resource planning, and large transaction processing. These applications are so important to the company’s success that they must be available around the clock. Pausing them to update software could be costly for the organization, or even endanger national security in some cases.
Airlines use mainframes to keep track of flight networks and passengers, a huge task that requires the ability to handle enormous amounts of data quickly and accurately. These systems are also used by many traditional brick-and-mortar stores to manage inventory and by many online retailers as well.
Banks, both investment banks and plain-old retail banks, rely on mainframes to process the massive amount of transactions they generate. From credit card processing and ATM withdrawals to online account updates, these systems provide the reliability and scalability that commodity servers simply can’t match.
There were several mainframe competitors in the past, including Univac, Sperry, Amdahl, and GE. However, IBM now dominates the market for these computers. Until recently, mainframes were so expensive that only very large companies could afford them. However, recent advancements in cloud computing and clustering have made them more affordable for smaller businesses as well. For this reason, mainframes will continue to play an essential role in many industries for years to come.