A mainframe is a large computer with which terminals can be connected to many people at once. Thousands of dumb terminals are used with large mainframe computers . This computer has multiple processing parts. Large organizations use such computers. Mainframe computers are needed for the management, control, analysis and evaluation of banks , insurance , financing institutions and scientific activities . The Atomic Energy Commission mainframe computer was first installed in Bangladesh in 1975. After that mainframe was established in Bangladesh University of Engineering , Bangladesh Bureau of Statistics , Power Development Board , Bangladesh Export Import Company etc. Computers in UNIVAC 1100/01, IBM 4341, NCR N 8370 etc. are included in this category. Mainframe systems: enterprise systems , super servers , transaction processing , supercomputers, etc.