Characteristics of computers:
Computers of all sizes have common characteristics – speed, arithmetical and logical operations, accuracy, reliability, storage, retrieving data and programs, automation, versatility, communications, diligence, feelings, consistency and precision. Computers are the foundation of business, travel, and leisure life today. Computers provide the processing speed required by all facets of society. The quick service we expect at the bank, at the grocery store, on the stock exchange, and on the Internet are dependent on the speed of computers. Can you imagine our world without computers? Computers are extremely reliable as well. Most errors are caused by humans, not computers. Computers are capable of storing enormous
amounts of data that must be located and retrieved very quickly. The capability to store and retrieve volumes of data is at the core of the Information Age. Now-a-days computer is playing a main role in everyday life it has become the need of people just like television, telephone or other electronic devices at home. It solves the human problems very quickly as well as accurately. The important characteristics of a computer are
The computer is a very high speed electronic device. The operations on the data inside the computer are performed through electronic circuits according to the given instructions. The data and instructions flow along these circuits with high speed that is close to the speed of light. Computer can perform millions of billions of operations on the data in one second. The computer generates signals during the operation process therefore the speed of computer is usually measure in megahertz (MHz) or Giga hertz (GHz). It means million cycles units of frequency is hertz per second. Different computers have different speed.
- Arithmetical and Logical Operations
A computer can perform arithmetical and logical operations. In arithmetic operations, it performs the addition, subtraction, multiplication and division on the numeric data. In logical operation it compares the numerical data as well as alphabetical data.
In addition to being very fast, computer is also very accurate device. It gives accurate output result provided that the correct input data and set of instructions are given to the computer. It means that output is totally depended on the given instructions and input data. If input data is in-correct then the resulting output will be in-correct. In computer terminology it is known as garbage-in garbage-out.
The electronic components in modern computer have very low failure rate. The modern computer can perform very complicated calculations without creating any problem and produces consistent (reliable) results. In general, computers are very reliable. Many personal computers have never needed a service call. Communications are also very reliable and generally available whenever needed.
A computer has internal storage (memory) as well as external or secondary storage. In secondary storage, a large amount of data and programs (set of instructions) can be stored for future use. The stored data and programs are available any time for processing. Similarly information downloaded from the internet can be saved on the storage media.
- Retrieving data and programs
The data and program stored on the storage media can be retrieved very quickly for further processing. It is also very important feature of a computer.
A computer can automatically perform operations without interfering the user during the operations. It controls automatically different devices attached with the computer. It executes automatically the program instructions one by one.
Versatile means flexible. Modern computer can perform different kind of tasks one by one of simultaneously. It is the most important feature of computer. At one moment you are playing game on computer, the next moment you are composing and sending emails etc. In colleges and
universities computers are used to deliver lectures to the students. The talent of computer is dependent on the software.
Today computer is mostly used to exchange messages or data through computer networks all over the world. For example the information can be received or send through the internet with the help of computer. It is most important feature of the modern information technology.
A computer can continually work for hours without creating any error. It doesnot get tired while working after hours of work it performs the operations with the same accuracy as well as speed as the first one.
Computer is an electronic machine. It has no feelings. It detects objects on the basis of instructions given to it. Based on our feelings, taste, knowledge and experience: we can make certain decisions judgments in our daily life. On the other hand, computer cannot make such judgments on their
own. Their judgments are totally based on instructions given to them.
People often have difficulty to repeat their instructions again and again. For example, a lecturer feels difficulty to repeat a same lecture in a class room again and again. Computer can repeat actions consistently (again and again) without losing its concentration:
To run a spell checker (built into a word processor) for checking
spellings in a document.
To play multimedia animations for training purposes.
To deliver a lecture through computer in a class room etc.
A computer will carry out the activity with the same way every time.
You can listen a lecture or perform any action again and again.
Computers are not only fast and consistent but they also perform operations very accurately and precisely. For example, in manual calculations and rounding fractional values (That is value with decimal point can change the actual result). In computer however, you can keep the accuracy and
precision upto the level, you desire. The length calculations remain always accurate.
1.5 Organization of a Computer
A computer is a fast and accurate device, which can accept data, store data, process them and give, desired results as output. The computer is organized into four units such as, Input unit, CPU, Secondary memory and
Output unit as shown in the following diagram.
projects through the bottom surface rotates as the mouse is moved along a flat surface and sends electrical signals to the system unit by means of switches inside the mouse. This causes the cursor, or pointer, to move in a corresponding fashion. An Optical mouse uses diodes to emit light beam
instead of a rotating ball to detect movement across a specially patterned metal pad.
- Light Pen
with a mouse the cursor stops moving as soon as you stop moving the mouse. With a joystick, the pointer continues moving in the direction the joystick is pointing. To stop the pointer, you must return the joystick to its upright position. Most joysticks include two buttons called triggers. Joysticks
are used mostly for computer games, but they are also used occasionally for
CAD/CAM systems and other applications.
Some sub-notebook computers (such as the IBM ThinkPad), which lack room for even a touch pad, incorporate a track point, a small rubber projection embedded between the keys of the keyboard. The track point acts like a little joystick that can be used to control the position of the on-screen cursor.
A graphics tablet consists of an electronic writing area and a special “pen” that works with it. Graphics tablets allow artists to create graphical images