Friday 26 April 2013

compuetr system-an overview


COMPUTER SYSTEM-AN OVERVIEW….


WHAT IS COMPUTER ?
A computer is a general purpose device that can be to carry out a finite set of arithmetic or logical operations. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.
Conventionally, a computer consists of at least one processing element, typically a  (CPU) and some form of memory The processing element carries out arithmetic and logic operations, and a sequencing and control unit that can change the order of operations based on stored information. Peripheral devices allow information to be retrieved from an external source, and the result of operations saved and retrieved.
FUNCTIONING OF COMPUTER ?
The main and also basic function of a computer is to run programs. The programs they run can help to improve humans' every day lives.
But, there are four basic functions of a Computer. They are:
1. INPUT- you input data i.e. you provide data; set of instructions You input data through input devices which are keyboard, mouse, etc
2. PROCESSING- the computer processes it i.e. it manipulates the data which is done by the C.P.U
3. OUTPUT- After processing the data the computer displays the result , it gives an output. Output devices are the monitor, in the case of visual output. speakers, in the case of audio output, printers, etc
4. STORAGE- You can save your data for future use in the CPU itself which is stored in the computer's ROM. There are several other storage devices also like removable disks , CDs, etc
FUNCTIONING COMPONENTS OF COMPUTER SYSTEM

Computer systems ranging from a controller in a microwave oven to a large supercomputer contain components providing five functions. A typical personal computer has hard, floppy and CD-ROM disks for storage, memory and CPU chips inside the system unit, a keyboard and mouse for input, and a display, printer and speakers for output. The arrows represent the direction information flows between the functional units.
BASIC APPLICATIONS
This program prepares students for employment in a variety of entry-level office positions.  You receive hands-on computer training in the Windows operating system and the popular software applications found in Microsoft Office, including Microsoft Word, Excel, Access, PowerPoint, and Publisher.  Keyboarding skills are recommended for entering students.

CHARACTERISTICS OF A COMPUTER
Let us identify the major characteristics of computer. These can be discussed under the headings of speed, accuracy, diligence, versatility and memory.
Speed
As you know computer can work very fast. It takes only few seconds for calculations that we take hours to complete. Suppose you are asked to calculate the average monthly income of one thousand persons in your neighborhood. For this you have to add income from all sources for all persons on a day to day basis and find out the average for each one of them. How long will it take for you to do this? One day, two days or one week? Do you know your small computer can finish this work in few seconds? The weather forecasting that you see every day on TV is the results of compilation and analysis of huge amount of data on temperature, humidity, pressure, etc. of various places on computers. It takes few minutes for the computer to process this huge amount of data and give the result.
You will be surprised to know that computer can perform millions (1,000,000) of instructions and even more per second. Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second) or nano-second (10-9 part of a second). From this you can imagine how fast your computer performs work.
Accuracy
Suppose some one calculates faster but commits a lot of errors in computing. Such result is useless. There is another aspect. Suppose you want to divide 15 by 7. You may work out up to 2 decimal places and say the dividend is 2.14. I may calculate up to 4 decimal places and say that the result is 2.1428. Some one else may go up to 9 decimal places and say the result is 2.142857143. Hence, in addition to speed, the computer should have accuracy or correctness in computing.
The degree of accuracy of computer is very high and every calculation is performed with the same accuracy. The accuracy level is determined on the basis of design of computer. The errors in computer are due to human and inaccurate data.
Diligence
A computer is free from tiredness, lack of concentration, fatigue, etc. It can work for hours without creating any error. If millions of calculations are to be performed, a computer will perform every calculation with the same accuracy. Due to this capability it overpowers human being in routine type of work.
Versatility
It means the capacity to perform completely different type of work. You may use your computer to prepare payroll slips. Next moment you may use it for inventory management or to prepare electric bills.
Power of Remembering
Computer has the power of storing any amount of information or data. Any information can be stored and recalled as long as you require it, for any numbers of years. It depends entirely upon you how much data you want to store in a computer and when to lose or retrieve these data.
No IQ
Computer is a dumb machine and it cannot do any work without instruction from the user. It performs the instructions at tremendous speed and with accuracy. It is you to decide what you want to do and in what sequence. So a computer cannot take its own decision as you can.
No Feeling
It does not have feelings or emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users.
Storage
The Computer has an in-built memory where it can store a large amount of data. You can also store data in secondary storage devices such as floppies, which can be kept outside your computer and can be carried to other computers.

TYPES OF COMPUTER
To describe the various types of computers viz., super computers, mainframe computers, mini computers, micro computers, desktop computers, laptop computers ,ETC.
CONVERGENCE OF TECHNOLOGIES
Technological convergence is the tendency for different technological systems to evolve toward performing similar tasks. Convergence can refer to previously separate technologies such as voice (and telephony features), data (and productivity applications), and video that now share resources and interact with each other synergistically.
The rise of digital communication in the late 20th century has made it possible for media organizations (or individuals) to deliver text, audio, and video material over the same wired, wireless, or fiber-optic connections. At the same time, it inspired some media organizations to explore multimedia delivery of information. This digital convergence of news media, in particular, was called "Mediamorphosis" by researcher Roger Fidler [2], in his 1997 book by that name. Today, we are surrounded by a multi-level convergent media world where all modes of communication and information are continually reforming to adapt to the enduring demands of technologies, "changing the way we create, consume, learn and interact with each other".[1]
Convergence in this instance is defined as the interlinking of computing and other information technologies, media content, and communication networks that has arisen as the result of the evolution and popularization of the Internet as well as the activities, products and services that have emerged in the digital media space. Many experts view this as simply being the tip of the iceberg, as all facets of institutional activity and social life such as business, government, art, journalism, health, and education are increasingly being carried out in these digital media spaces across a growing network of information and communication technology devices.
Also included in this topic is the basis of computer networks, wherein many different operating systems are able to communicate via different protocols. This could be a prelude to artificial intelligence networks on the Internet eventually leading to a powerful superintelligence[2] via a technological singularity.

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