CHAPTER-1

We will start with an introduction that why to use maifram computers? and advantages compared to other computers.

Mainframe computers can process several million-program instructions per second.Large organizations rely on these room-size systems to handle large programs with lots of data.These Mainframes are mainly used by insurance companies, banks, airline and railway reservation systems. Mainframes have even more access space and also to input/output devies.They have powerful processors.I explained about these processors in chapter 1.1. This power is useful and required by large corporations who have large amount of data process. Here i will give an small and regular example like generally banks has large data they need to update accounts regularly so they need powerful machines to process this data.These large banks use mainframe computers to maintain their customer account records. so that if customer want to withdraw or deposit money at any branch at any time he can acess easily because his data is already getting up-to-date.So from anywhere he can access his account.

we can compare use of mainframes to micro and mini computers also.

Micro Computers are small, single user systems that provide a simple processor and just few input/output devices.The micro computer is also known as "Personel Computer" As we see them regularly in homes and offfices. This is so called "micro" because the fundemental component that allowed the categories development was CPU created on single chip created with introduction of "microprocessors". When larger systems were focussed on productivity of whole department or organization,the micro computer was only effective for single individual's work.

Mini computers are mid range computers were first developed as special-purpose mainframe computers.They were used, for instance,to control machines in a manufacturing unit.However, now they are widely used as general-purpose computers.They are known as Distributed Data processing i.e company processing power is decentralized.That means end users can process at their own micro computers. Mini computers are used by medium sized business and small sites of large organizations.They are used in factories to control automated assembly lines,manufacturing,process control e.t.c

The important thing to note for minicomputers and mainframes is the reliability of the machine. As it generally has to operate 24 hours.Ofcourse in companies every minute of operation is important.If it does not work for a minute also it is calculated as a huge loss for the company so for these purposes micro computers are not prefferd.They have to rely on room-size systems.

Mainframe computers can handle several million-program instructions per second.They have powerful hardware and CPU chips that can support heavy work inflow which can also be used for making complex calculations, and designs.So they are also called as super computers.