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What is a Mainframe Computer?

Last Updated : 26 May, 2020
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Mainframes are a type of computers, which are made for ‘throughput’ as fast as possible; a throughput can be defined as “the rate at which the data is processed” . And also mainframes are majorly used for transaction processing; a transaction can be defined as “a set of operations including disk read and write, operating system calls, transferring data from one subsystem to another, etc…”


The mainframes have more processing power compared to servers and microcomputers (like- laptop, PC, etc…), but have less processing power compared to a supercomputer.
The main focus of the Main-frames is throughput, “A throughput is a rate at which something is processed.”

Components of a Mainframe Computer

The mainframes have two types of processors, the first one is the Main processor and another one is System assistance Processor or SAP. The SAP processors do not process any data but move the data from one place to another as fast as possible.
Each processor can have up to 7 to 10 cores which are specially designed and engineered for ‘higher throughput’.
Each mainframe can have up to 160 of I/O cards. And also they have got some serious amount of ROM (Solid State Drives) for faster data storage and transfer.

The fact that the main-frames have so many I/O cards is because these are made for redundancy that is, if one card fails, other cards will take over the work-load of that card until the card is replaced.

Why are mainframe computers used?

Main-frames are used for Reliability, Redundancy, and availability. These are must computers to have where ‘0’ downtime is acceptable.
Due to the fact that these computers are reliable and have redundancy that is if an I/O card fails due to any reason, its workload will automatically get transferred to other I/O card ensuring ‘0’ downtime which is of great importance for ensuring proper transactions.
Similarly, if there is some problem with a processor module, the workload will be transferred to other processors.

How are Mainframes different from Supercomputer?

The Main-Frames are used for fast processing or ‘throughput’ whereas the Supercomputers are used for number crunching where they deal with a colossal amount of data to predict weather, solve complex mathematical models for computation and are majorly used in research only.


  • The processing speed is very fast.
  • Can handle multiple inputs at same time.
  • Redundancy, Can withstand failure of a part without affecting the function of rest of the computer.
  • Always available, as once started they will remain on for rest of the time.
  • Reliability.


  • Mainframes cannot be used as a normal computer, because they are made for specific task only.
  • It requires a special OS to run.
  • Are very expensive.
  • Mainly used for commercial purposes like transaction processing.
  • Cannot calculate or solve complex problems like a supercomputer.

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