The evolution of computer systems : from mainframe computer systems to microcomputer systems.

Mainframes- system are large and "expensive" computers used mainly by government institutions and large companies for mission critical applications, or have the ability to run (or host) multiple operating systems, and thereby operate not as a single computer but as a number of virtual machine.for exmple, mainframe can process thousands of million instructions per second (MIPS). typically bulk data processing such as censuses, industry/consumer statistics, ERP, and financial transaction processing.Mainframes are large & high power computers which is used in large organizations, or companies for mission crucial applications like censuses or even in weather forecast.
Over the years they have evolved from hall-sized dinosaurs to fully IP-networked machines that are extremely competitive and cost effective platform for e-commerce and hosting. According to a year 2002 estimate "70 % of the world's data is on the mainframes, and 85 % of all business transition are still processed on mainframes, but mainframe have slimmed down drastically in the few years, dramatically reducing their acquisition and operating costs.


The term "Microcomputer" came into popular use after the introduction of the minicomputer, although Isaac Asimov used the term microcomputer in his short story "The Dying Night" as early as 1956 (published in The Magazine of Fantasy and Science Fiction in July that year). Most notably, the microcomputer replaced the many separate components that made up the minicomputer's CPU with a single integrated microprocessor chip.Microcomputers are the most important category of computer system for both business and consumers.through usually called a personal computer, PC for use by an individual.A microcomputer contains a center processing unit (CPU) on a microchip (the microprocessor), a memory system (typically read only memory and random access memory ), a bus system and I/O ports, typically housed in a motherboard. They are more powerful microcomputers that coordinate telecommunications and resource sharing in small local are networks ( LANs) and in internet and intranet website.