Accessing Your Old Mainframe Programs

Mainframe computers offer specialised functions and are therefore favoured by a variety of organisations. It is similarly important for some businesses to be able to access their old mainframe programs, even if they now use new or different programs.

What is a mainframe computer?

Mainframe computers, sometimes referred to as ‘big iron’, are particularly powerful types of computers that are extensively used by organisations of a corporate and government nature. Mainframe computers are commonly used for the storage and bulk data processing of important applications, including:

• Census, consumer and specific industry statistics
• Transaction processing (an area of particular significance to banks and financial institutions, making Windows terminal emulators critically important and infinitely useful)
• Resource planning for different types of enterprises

At first, the term ‘mainframe computers’ referred to the large cabinets that were needed to accommodate the central processing unit and memory of computers. However, this term has since been used to separate high-end commercial computers from their less powerful counterparts.

Features of mainframe computers

Mainframe computers are widely recognised for the high levels of reliability and security that they provide, together with their impressive input/output capabilities. Incredible amounts of throughput are enabled by these machines and one of their most notable and important features is the way that they offer backward compatibility with older versions of software. This feature is significant in providing access to old mainframe programs.

Mainframe computers are of course used in different contexts but are commonly run without interruption for long periods of time; it is because they are renowned and have proven stability and reliability that they are so often used in this way. In fact, the term RAS (reliability, availability and serviceability) is a frequently cited characteristic of mainframe computers and, therefore, it comes as little surprise that these computers are used in situations where system failure is not only undesirable but costly, damaging and even disastrous. The banking and financial industry makes extensive use of terminal emulators for this reason.

The impressive availability of mainframes explains why they have been used so widely for so long, and because there is good opportunity to access old mainframe programs, users tend to feel that mainframe computers are safe and effective in the long term.

Since 2000 and in response to significant technological developments, contemporary mainframes have almost completely replaced traditional terminal access of end-users in preference to web user interfaces.

Characteristics of mainframe computers

• Multiple operating systems can be hosted by most mainframe computers and this enables a number of virtual machines to operate from them. This characteristic allows mainframe computers to perform the roles of some hardware services that are characteristically higher functioning.
• In a number of businesses that make use of mainframe computers, two machines operate: one of these is located in the primary data centre of the business, while the other is found in the designated backup data centre. If something catastrophic occurs that will affect the first building, data and programs that are safely backed up can be accessed and used.
• By design, mainframes can manage high volumes of both input and output and recent versions have a reduced impact on the central processing unit (CPU) of the computer, leaving it to deal only with high-speed memory.
• Mainframe computers commonly handle and organise extensive databases and files (gigabyte to terabyte sized files are not uncommon). This characteristic certainly distinguishes mainframe computers from typical PCs, because mainframes enable storage of hundreds to thousands of times as much data online, with more rapid access.

Mainframe computers offer a range of advantages for businesses with specific data needs. The nature and characteristics of mainframe computers mean that massive amounts of data can be held and the benefits of reliability, availability and serviceability are provided through mainframes, more than other computing systems.

Availability of data and programs is important in many business contexts and mainframe computers generally enable access to old mainframe programs.