Introduction Of Mainframe

Mainframe computers ("big iron") are computers used primarily by large organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and transaction processing. It is the high performance computer supporting multiple user at the same time. It provides the high security and processes the millions of data.

Mainframe can use for:-

• Reliability:- System can recover from failure 
• Availability : - Recover data or component without affecting other programs. 
• Serviceability:- System itself find what has been wrong and give message 
• Scalability:-Upgrading to high configuration Security Compatibility

Classification of Computer:-

Computers are broadly classified into 4 types i.e

Microcomputer (Personal Computer) :

A microcomputer is the smallest general purpose processing system. The older pc started 8 bit processor with speed of 3.7MB and current pc 64 bit processor with speed of 4.66 GB. Examples: - IBM PCs, APPLE computers Microcomputer can be classified into 2 types :

1. Desktops 
2. Portables

The difference is portables can be used while travelling whereas desktops computers cannot be carried around.The different portable computers are: -

• Laptop 
• Notebooks 
• Palmtop (hand held) 
• Wearable computers

Minicomputer:

A minicomputer is a medium-sized computer. That is more powerful than a microcomputer. These computers are usually designed to serve multiple users simultaneously (Parallel Processing). They are more expensive than microcomputers. Examples: Digital Alpha, Sun Ultra.

Mainframe computers: -

Computers with large storage capacities and very high speed of processing (compared to mini- or microcomputers) are known as mainframe computers. They support a large number of terminals for simultaneous use by a number of users like ATM transactions. They are also used as central host computers in distributed data processing system. Examples: - IBM 370, S/390.

Supercomputer: -

Supercomputers have extremely large storage capacity and computing speeds which are many times faster than other computers. A supercomputer is measured in terms of tens of millions Instructions per second (mips), an operation is made up of numerous instructions. The supercomputer is mainly used for large scale numerical problems in scientific and engineering disciplines such as Weather analysis. Examples: - IBM Deep Blue.

Characteristics of Multi-programming:-

• Multiple virtual storage 
• Multi-programming SPOOL(Simulator Peripheral Operation Online) 
• Batch Address Space DAT(Dynamic Address Transaction )

Mainframe include the important concept:-

• COBOL 
• VSAM 
• CICS 
• JCL 
• DB2