Mainframe computer or mainframe is also known as a central computer. It is a large, powerful and expensive computer, mostly used by large companies for bulk data processing, and critical applications. It processes a large amount of data and uses in the processing of bank transactions, census, statistical work, etc.
It has the capability of performing millions of instructions per second (MIPS). They also have the ability to work uninterruptedly, even if you have to change some component of the mainframe. Its modular design allows you to work without stopping and without re-starting.
History of Mainframe Computer:
Several manufacturers were those who produced central units in the 1960s and 1970s. In the days of a boom of these machines, the manufacturers were known because their number was not very large: IBM, Burroughs, Control Data, General Electric, Honeywell, NCR, RCA, and Univac. Among European manufacturers, Telefunken, Siemens, and Olivetti stood out. But low demand and great competition caused a great tremor in the market. RCA was bought by Univac, and General Electric left the computer market. Honeywell was acquired by Bull, Univac joined Sperry to form Sperry / Univac, which in 1986 joined Burroughs to form Unisys Corporation. For its part and in 1991, AT&T briefly owned NCR.
The companies realized that servers based on microcomputer designs could be installed at a much lower cost, and offer local users greater control of their systems, and the false terminals used to connect to central unit systems They were gradually replaced by personal equipment. Consequently, demand plummeted, and large central unit facilities were mostly restricted to financial institutions with large data processing needs. For a time, there was a consensus within industry analysts that the central unit market was over since the central unit platforms were in many cases replaced by personal unit networks.
This trend ended in 1990 as companies found new uses for their central units because they could now offer web servers with a power similar to that of hundreds of small personal computers, but with much less electricity consumption and lower administrative costs.
Another factor that increased the use of central units in practice was the development of the GNU / Linux operating system, which is capable of running on many different central unit systems, directly or, more frequently, through a virtual machine. This allows the central units to take advantage of the programming experience and the personal equipment market communities.
Mainframe Computer Capacity
The capacity of a central unit is defined both by the speed of its CPU and its large internal memory, its high and large external storage capacity, its results in fast and considerable I / O devices, the high quality of its internal engineering which results in high reliability and expensive technical support, but of high quality. A central unit can operate for years without problems or interruptions and repairs can be made while it is running. Central unit vendors offer special services; For example, if the equipment is broken, the seller will run the applications of his client in his units without the users noticing while the repairs last. The internal independence of these units is so great that, at least. The technicians were able to change the central units of the site by disassembling them piece by piece and assembling them in another place, leaving, in the meantime, said equipment working; In this example, the change of the central units from one site to another occurred transparently.
Often, the central units support thousands of users simultaneously that are connected by false terminals. Some central units can run or shelter many operating systems and therefore do not work as a single unit, but as several virtual machines. In this role, a central unit alone can replace dozens or hundreds of small personal equipment, reducing administrative and management costs while offering much better scalability and reliability. Reliability is achieved by the independence of its internal components noted above, and scalability is achieved because the physical resources of the unit can be redistributed between virtual terminals according to needs; This is much more difficult to do with personal equipment, because to remove or add new physical components you have to unplug the equipment many times and the limitations of these components are much greater. When a central unit acts as the center of operations for many virtual terminals, it can offer the power necessary for these units to operate efficiently, but also the flexibility of personal equipment networks.
Features of Mainframe Computer:
Vel. Process: Hundreds of millions of instructions per second or more.
Users at a time: Hundreds or thousands.
Size: Require special facilities and air conditioning.
Ease of use: For specialists.
Usual clients: Large corporations and governments.
Social Penetration: Low.
Social impact: Very high, although it goes unnoticed, modern industrial society cannot function without them.
Park installed: Thousands worldwide.
Cost: Hundreds or thousands of dollars or more.
Application of Mainframe Computer:
Unlike Supercomputer, they offer a versatile and simplified work environment, high processing speeds at a very low cost compared to those mentioned above. They have much more applications than Supercomputer since they are more affordable to the corporate market, being the solution for supermarkets and companies. Some of the applications are:
Administration and support for large networks, as well as a web application server and dynamic and remote access databases.
Scientific research of low and medium level, and in some cases isolated from a higher level, such as in the development of interactive simulations on the behavior of a substance X in the presence of a substance Y, developing new drugs and chemical substances.
In the meteorological stations, allowing the development of animations about the climate and the possible consequences in certain situations.
In civil engineering, in the construction of more efficient construction plans and models, such as buildings capable of supporting cyclones, tornadoes, and earthquakes, as well as better use of the environment, such as space, light, natural air conditioning, etc.
Example of Mainframe Computer:
IBM system 3 and AS-400, IBM 709, IBM 4381, IBM zSeries, System z9 and System z10 servers, ICL 2900, NEC 610.