Personal Computer and its uses-1

INTRODUCTION OF PERSONAL COMPUTER AND ITS USES

Computers were first used in management and business applications in centralized data processing departments. These departments were manned by computer specialists who were the only persons allowed access to the machines. Later terminals were provided to users for certain applications. However, cost, complexity, size and the need for special environment control did not permit computer users to have computers at their work places. All this has changed with the advent of micro-computers. For example market type is also change now a day than before. New days companies are using trade show booths where they have banner stands, table skirts and pipe and drape. Same way, computers are changing day by day with the use of new technology being invented and introduced in the market. Marketing exhibitions and trades shows are best way to introduce new technology to people.

 

MICRO-COMPUTERS

Micro-computers are computers which have their entire Central Processing Unit (CPU) on single integrated circuit ‘chip’ (called a micro-processor). Today powerful micro-computers are available which cost as little as $ 500. These micro-computers can do many of the jobs earlier done by large computers which cost many times this amount. In addition, because they are small enough to sit on a desk and do not require extensive environmental control, they can be used in most reasonably dust-free environments. Field tests on machines used in projects such as the Computer Literacy Project for Secondary Schools of the Education Ministry have shown this.

 

This ready availability for users has enabled a large number of entirely new applications to be undertaken. It has also increased user interest in computing since users can be directly in control of their data unlike the situation with centralized computing. Due to these factors and the fact that micro-computers can be used at home and schools for education and entertainment there has been a spectacular increase in their numbers since their first arrival as hobby kits in the U.S. Several million micro-computers are used in management applications around the world today. In India the projections are that by 1990 a few lakhs of these machines will be installed.

Classification Of Computers

 

In the 1970s computers were classified into three categories, namely, super-computers, large computers and mini computers. But the invention of the micro-processor which gave birth to micro-computers in the late 70s has drastically changed the computing scene. A wide range of computers are available today in the market ranging from a personal computer to a super computer.

 

A personal computer (PC) is a micro-computer which has its entire central processing unit on a single micro-processor chip. A PC provides a main memory capacity upto 640 kilo bytes and a processing power of 0.5 MIPS. It supports one or 2 diskette drives of 360 KB each for random access secondary memory. A PC usually comes with a standard key board, a visual display unit and a dot matrix printer. A PC is usually operated by a single user.

 

A super mico-computer has its entire central processing unit on a very powerful micro-processor, provides a main memory capacity of upto 16 mega bytes, has a processing power of 2 to 3 MIPS, supports Winchester disks of capacity 20 to 80 mega bytes and allows simultaneously access to multiple users. Today’s super micro is actually replacing yesterday’s mini computers which provide almost the same computing power it nit less, but based on a different technology.

Operating Systems

An operating system is the most important system software and is required to operate a computer system. An operating system manages a computer’s resources very effectively, takes care of scheduling multiple jobs for execution and manages the flow of data and instructions between the input/output units and the main memory.

 

Operating systems became a part of computer software with the second generation computers. Since then operating systems have undergone several revisions and modifications in order to achieve a better utilization of computer resources. Advances in the field of computer hardware have also helped the development of more efficient operating systems.

 

The first operating system called batch processing (serial) operating system was developed for the second generation computers; This operating system executes jobs serially one after another from a batch of jobs submitted for execution. The central processing unit is kept busy only during the processing cycle of a job and it idles during the input and output operations.

 

The above drawback of idling the CPU was overcome with the introduction of overlapped processing. For example why not take up input operation of job 2 and the output operation of job 1 simultaneously? This and similar considerations gave rise to the concept of multi-programming. A multi-programming operating system handles multiple jobs simultaneously by overlapping the input, output and processing cycles of various jobs.