Data Transmission Modes

Data Transmission Modes

There are three ways for transmitting data from one point to another -

1.Simplex: In simplex mode the communication can take place in one direction. The receiver receives the signal from the transmitting device. In this mode the flow of information is Uni.-directional. Hence it is rarely used for data communication.

2.Half-duplex: In half-duplex mode the communication channel is used in both directions, but only in one direction at a time. Thus a half-duplex line can alternately send and receive data.

3.Full-duplex: In full duplex the communication channel is used in both directions at the same time. Use of full-duplex line improves the efficiency as the line turn-around time required in half-duplex arrangement is eliminated. Example of this mode of transmission is the telephone line.

What Are The Basic Functions Of Operating System ?

BASIC FUNCTIONS OF OPERATING SYSTEM

Different types of operating system are used for different purpose.Their size and complexity vary from operating system to operating system. The following are the various function of an operating system , they are

1. Managing Resource.
2. Providing User Interface.
3. Running Application.
4. Support For Utility Program.
5. Controls Computer Hardware.

1. Managing Resource : The operating system manage the resource to execute the task within the computer system depending upon their arrival in the ready Que.

2. Providing User Interface : The operating system provides the user interface to the user to interact with the computer system. The interfaces are -

• Command User Interface ( CUI ).
• Graphical User Interface ( GUI ).

Ready Que means the no. of process arrival to perform their task with in the central processing unit.

3. Running Application : The operating system provides the input / output resource to execute the task with in our computer system. The process execute program that has to be loaded in the Random Access Memory (RAM) from the hard disk.

For Example - When we write a letter 1st we have to load and run the MS Word, when we request to run a program the operating system locates the program or application in the hard disk and load the program to the Random Access Memory or Primary Memory.

4. Support For Utility Program : When a system raises a error or the system is corrupted or the system is virus effected or insufficient memory at that time the utility program solve our problem by using the following base -

• Formatting.
• Back Up Recovery.
• Disk Defragmenter.
• Installation.
• Uninstallation.

5. Controls Computer Hardware : The operating system supervises all the hardware devices connected with the computer system. It gives us an idea about the status of our hardware devices that they are properly connected or not. The operating system also provides one of the technique which is known as BIOS (Basic Input Output System). Through BIOS we can maintain the system information like the system password, capacity of ram, etc.

What Are The Different Types Of System Software? Explain

DIFFERENT TYPES OF SYSTEM SOFTWARE 

The System Software are divided into 3 types, They are :

1. Operating System Software
2. System Software
3. Utility Software

1. Operating System Software (O.S) : An Operating System is a program designed to run other programs on a computer. A computer's operating system is its most important program. It is considered as trhe backbone of a computer managing both software and hardware device. Operating systems are responsible for each and everything from the control and allocation of memory to input from external devices and output to computer display.

An operating system also plays a vital role in security. Its job includes preventing unauthorized user from accessing the computer system

There various types of operating system are -

• General Purpose O.S
• Special Purpose O.S
• Batch Processing O.S
• Single Use O.S
• Multi-User O.S
• Multi-Programming O.S
• Multi-Processing O.S
• Multi-Threading O.S
• Real Time O.S
• Embedded O.S

2. Language Translator : It is another system software which convert the high level language to machine level language for the purpose of machine understanding.

The Machine can only understand the machine level language or binary language 0's & 1's. The language translator rectify the errors within the program through different ways.

There are 3 types of language translator, they are as follows :-

• Compiler.
• Interpreter.
• Assembler.

3. Utility Software : Utility Software is a kind of system software designed to help, analyse, configure, optimize and maintain the computer. A single piece of utility software is usually called a utility or tool.

If we are having any problem related to system then we can solve it through utility software.

For example - Antivirus:- Utility scan for computer virus.

                      - Memory tester check's for memory failure etc.

The following are the activities those are coming under the utility software are -

• Formatting.
• Back-Up Recovery.
• Disk Defragmenter.
• Registry Cleaners.
• Disk Partitions. Etc

What Are The Different Types Of Computer With Examples (Based On The Processing & Storing Capabilities)

TYPES OF COMPUTERS 

(Based On The Processing & Storing Capabilities)

Now let us discuss the varieties of computers that we see today. Although they belong to the fifth generation they can be divided into different categories depending upon the size, efficiency, memory and number of users.There are 5 types of computer based on the processing and storing capabilities, they are

• Micro Computer
• Mini Computer
• Mainframes
• Super Computer
• Embedded Computer

• Micro Computer: Microcomputer is at the lowest end of the computer range in terms of speed and storage capacity. Its CPU is a microprocessor. The first microcomputers were built of 8-bit microprocessor chips. The most common application of personal computers (PC) is in this category. The PC supports a number of input and output devices. An improvement of 8-bit chip is 16-bit and 32-bit chips. Examples of microcomputer are IBM PC, PC-AT .

• Mini Computer:
This is designed to support more than one user at a time. It possesses large storage capacity and operates at a higher speed. The mini computer is used in multi-user system in which various users can work at the same time. This type of computer is generally used for processing large volume of data in an organisation. They are also used as servers in Local Area Networks (LAN). 

• Mainframes: These types of computers are generally 32-bit microprocessors. They operate at very high speed, have very large storage capacity and can handle the work load of many users. They are generally used in centralised databases. They are also used as controlling nodes in Wide Area Networks (WAN). Example of mainframes are DEC, ICL and IBM 3000 series. 

• Super Computer: They are the fastest and most expensive machines. They have high processing speed compared to other computers. They have also multiprocessing technique. One of the ways in which supercomputers are built is by interconnecting hundreds of microprocessors. Supercomputers are mainly being used for whether forecasting, biomedical research, remote sensing, aircraft design and other areas of science and technology. Examples of supercomputers are CRAY YMP, CRAY2, NEC SX-3, CRAY XMP and PARAM from India. 

• Embedded Computer: This Type Of Computer is used in a small chip. This means the small chip can be put inside other machines to control the devices. This type of technology is known as embedded computer. For Example - Mobile Phone, Washing Machine, Telephone, Telephone

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Explain Computer Generation & Various Types Of Computer Generation?

Q.2  EXPLAIN BRIEFLY ABOUT COMPUTER GENERATION & VARIOUS TYPES OF COMPUTER GENERATION?
 COMPUTER GENERATIONS: You know that the evolution of computer started from 16th century and resulted in the form that we see today. The present day computer, however, has also undergone rapid change during the last fifty years. This period, during which the evolution of computer took place, can be divided into five distinct phases known as Generations of Computers. Each phase is distinguished from others on the basis of the type of switching circuits used.

First Generation Computers: First generation computers used Thermion valves. These computers were large in size and writing programs on them was difficult. Some of the computers of this generation were:

• ENIAC: It was the first electronic computer built in 1946 at University of Pennsylvania, USA by John Eckert and John Mauchy. It was named Electronic Numerical Integrator and Calculator (ENIAC). The ENIAC was 30 50 feet long, weighed 30 tons, contained 18,000 vacuum tubes, 70,000 registers, 10,000 capacitors and required 150,000 watts of electricity. Today your favorite computer is many times as powerful as ENIAC, still size is very small.

• EDVAC: It stands for Electronic Discrete Variable Automatic Computer and was developed in 1950. The concept of storing data and instructions inside the computer was introduced here. This allowed much faster operation since the computer had rapid access to both data and instructions. The other advantages of storing instruction was that computer could do logical decision internally.

• EDSAC: It stands for Electronic Delay Storage Automatic Computer and was developed by M.V. Wilkes at Cambridge University in 1949.

• UNIVAC-1: Ecker and Mauchly produced it in 1951 by Universal Accounting Computer setup.

Limitations Of First Generation Computer: Followings are the major drawbacks of First generation computers.

1. The operating speed was quite slow.
2. Power consumption was very high.
3. It required large space for installation.
4. The programming capability was quite low.


Second Generation Computers: Around 1955 a device called Transistor replaced the bulky electric tubes in the first generation computer. Transistors are smaller than electric tubes and have higher operating speed. They have no filament and require no heating. Manufacturing cost was also very low. Thus the size of the computer got reduced considerably.

It is in the second generation that the concept of Central Processing Unit (CPU), memory, programming language and input and output units were developed. The programming languages such as COBOL, FORTRAN were developed during this period. Some of the computers of the Second Generation were

• IBM 1620: Its size was smaller as compared to First Generation computers and mostly used for scientific purpose. 
• IBM 1401: Its size was small to medium and used for business applications. 
• CDC 3600: Its size was large and is used for scientific purposes. 

Third Generation Computers: The third generation computers were introduced in 1964. They used Integrated Circuits (ICs). These ICs are popularly known as Chips. A single IC has many transistors, registers and capacitors built on a single thin slice of silicon. So it is quite obvious that the size of the computer got further reduced. Some of the computers developed during this period were IBM-360, ICL-1900, IBM-370, and VAX-750. Higher level language such as BASIC (Beginners All purpose Symbolic Instruction Code) was developed during this period.

Computers of this generations were small in size, low cost, large memory and processing speed is very high.

Fourth Generation Computers: The present day computers that you see today are the fourth generation computers that started around 1975. It uses large scale Integrated Circuits (LSIC) built on a single silicon chip called microprocessors. Due to the development of microprocessor it is possible to place computer’s central processing unit (CPU) on single chip. These computers are called microcomputers. Later very large scale Integrated Circuits (VLSIC) replaced LSICs.

Thus the computer which was occupying a very large room in earlier days can now be placed on a table. The personal computer (PC) that you see in your school is a Fourth Generation Computer.

Fifth Generation Computer: The computers of 1990s are said to be Fifth Generation computers. The speed is extremely high in fifth generation computer. Apart from this it can perform parallel processing. The concept of Artificial intelligence has been introduced to allow the computer to take its own decision. It is still in a developmental stage.


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Defination And Notes On : What Is Computer ? & What Are The Characteristics Of Computer ?

1. WHAT IS A COMPUTER? & WHAT ARE CHARACTERISTICS OF COMPUTER ? 


WHAT IS A COMPUTER : Computer is an electronic device. It can do arithmetic calculations faster. But as you will see later it does much more than that. It can be compared to a magic box, which serves different purpose to different people. For a common man computer is simply a calculator, which works automatic and quite fast. For a person who knows much about it, computer is a machine capable of solving problems and manipulating data. It accepts data, processes the data by doing some mathematical and logical operations and gives us the desired output.

Therefore, we may define computer as a device that transforms data. Data can be anything like marks obtained by you in various subjects. It can also be name, age, sex, weight, height, etc. of all the students in your class or income, savings, investments, etc., of a country. Computer can be defined in terms of its functions.

• It can accept the data,
• It can store the data,
• It can process the data as required by the user, 
• It can retrieve the stored data as and when required by the user,
• It can print the result in desired format. 

CHARACTERISTICS OF COMPUTER :

• Speed: Speed of the computer is wonderful. They can produce results instantaneously. A computer can do 10 lacs calculations in one second. The characteristic of speed is highly useful in various areas like space research, weather forecast, airplanes etc.

• Accuracy: Computers are highly accurate machines. They produce error free results. Any errors shown, is the result of wrong input entered in the computer. Errors are generally mammal. It has to do all those functions which it is instructed to do so.

• Storage: Computer can store enormous amount of data in it. The information can be retrieved from the storage devices almost instantaneously. Hard Disk (Magnetic Disk) is used to store the data. Think of storing a data on an 80 Giga byte on hard-disk. It can store nearly about - 10, 00, 000, 00 pages of data on it.

• Versatile: Computer is a versatile machine. It can perform the job instructed to it without any taking any break for a continued duration. Due to this characteristic, computers are working round the clock in various departments like Railway, Banks, Hospitals, Industries, etc.

• Diligence: Computer can work for a long time and does not suffer from the tiredness. It can perform the job several hours with same speed and accuracy.

• No Feeling: It does not have any feelings, emotion, taste, knowledge and experience. Thus it does not get tired even after long hours of work. It does not distinguish between users. 

• 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.
  
  

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