Types of Computer

 On the basis of data handling capabilities, the computer is of three types:

• Analogue Computer
• Digital Computer
• Hybrid Computer

 Analogue Computer

Analogue computers are designed to process analogue data. Analogue data is continuous data that changes continuously and cannot have discrete values. We can say that analogue computers are used where we don't need exact values always such as speed, temperature, pressure and current.

Digital Computer

Digital computer is designed to perform calculations and logical operations at high speed. It accepts the raw data as input in the form of digits or binary numbers (0 and 1) and processes it with programs stored in its memory to produce the output. All modern computers like laptops, desktops including smartphones that we use at home or office are digital computers.

Hybrid Computer

Hybrid computer has features of both analogue and digital computer. It is fast like an analogue computer and has memory and accuracy like digital computers. It can process both continuous and discrete data. It accepts analogue signals and convert them into digital form before processing. So, it is widely used in specialized applications where both analogue and digital data is processed. For example, a processor is used in petrol pumps that converts the measurements of fuel flow into quantity and price. Similarly, they are used in airplanes, hospitals, and scientific applications.

Advantages of using hybrid computers:

• Its computing speed is very high due to the all-parallel configuration of the analogue subsystem.
• It produces precise and quick results that are more accurate and useful.
• It has the ability to solve and manage big equation in real-time.
• It helps in the on-line data processing.

Difference between Analog Computer and Digital Computer :

S.No.	ANALOG COMPUTER	DIGITAL COMPUTER
01.	Analog computers works with continuous values or these types of systems process continuous data.	Digital computers works with discrete values or these types of systems process discrete data.
02.	Speed of analog computers is less than the digital computers.	Speed of digital computers is more than the analog computers.
03.	Analog computer has very low or limited memory and it can store less amount of data.	Digital computer has very big memory it can store large amount of data.
04.	Analog computer has no state.	Digital computer h .as On and Off these 2 steps.
05.	Analog computers are less reliable than digital computers.	Digital computers are more reliable than analog computers.
06.	Its performance is comparatively low.	Its performance is very high.
07.	Its speed of processing is not so high.	Its speed of processing is very high.
08.	Analog computers depends upon physical variations.	Digital computers does not depend upon physical variations.
09.	It provides results with less accuracy as compared to digital computers.	It provides results with higher accuracy as compared to analog computers.
10.	Analog computers are difficult to use.	Digital computers are not so difficult to use.
11.	Analog computers have complex architecture.	Digital computers do not have so complex architecture like analog computers.
12.	Readability of analog computer is low.	Readability of digital computer is high.
13.	Analog computers show the result in terms of voltage signals.	Digital computers show the result in computer display screen.
14.	Analog computers employs analog encoding.	Digital computers employs digital encoding.
15.	Power consumption is high.	Power consumption is low.
16.	They are usually special purpose devices.	It can be general purpose devices.
17.	Examples includes analog clock and thermometer etc.	Examples includes Digital laptop, digital camera, digital watches etc.

 

Tamil Nadu

 

Introduction

Tamil Nadu, or land of the Tamils, is the fourth largest state of India and is located in the extreme south of the Indian subcontinent. It is bounded by the Indian Ocean to the east and south, and by the states of Kerala to the west, Karnataka to the northwest, and Andhra Pradesh to the north. Along the north-central coast of Tamil Nadu are enclaves of Puducherry and Karaikal, both of which form part of the Puducherry union territory. Chennai (formerly known as Madras) is the capital city, located on the northeastern coast of the state. Tamil Nadu represents the Tamil-speaking area of what was formerly the Madras Presidency of British India.

Demographic Profile

According to Indian census data (2011), Tamil Nadu has a population of 72,147,030, an increase of 15.61 percent from 62,405,679 that was reported in the 2001 census. Tamil Nadu constituted 5.96 percent of India’s population in 2011.

Regions

North (Dharmapuri, Thiruvannamalai, Vellore and Krishnagiri districts)

North Coastal (Ariyalur, Chennai, Cuddalore, Kanchipuram, Nagapattinam, Tiruvallur and Tiruvarur districts)

West (Coimbatore, Erode, Nilgiris and Tirupur districts)

Central (Karur, Namakkal, Perambalur, Salem and Tiruchirappalli districts)

South West (Dindigul, Madurai, Theni and Virudhunagar districts)

South Coast (Pudukkottai, Ramanathapuram, Sivaganga and Thanjavur districts)

Far South (Kanniyakumari, Tuticorin and Tirunelveli districts)

North East (Villupuram district)

Tamil Nadu (Tamil: தமிழ்நாடு) is one of the states in India. The capital of this state is Chennai. Tamil is the language spoken in Tamil Nadu. Coimbatore, Tiruchirapalli, Salem, Madurai, Tirunelveli, Thanjavur and Thoothukudi are other large cities of Tamil Nadu. It is surrounded by the Bay of Bengal on the east and the Indian Ocean on the south and also by the Arabian Sea in the west for a smaller area. Kerala, Karnataka and Andhra Pradesh are its neighbouring states. The Tamilians are very proud of their language and heritage. In traditional Indian geography it falls under the South Indian zone.

The current chief minister of the state is Edapadi K. Palaniswamy from the All India Anna Dravida Munnetra Kazhagam(AIADMK). Its leader of the opposition is M.K.Stalin, who is also the leader of the Dravida Munnetra Kazhagam(DMK). These two Dravidian parties have been in power alternately in Tamil Nadu, since 1967.

         Tamil Nadu is the 11th largest state in India. The major river is Kaveri which meets the needs of agriculture. The other important rivers are south Pennar, Palar, Vaigai, Tamira bharani, Manimuthar, Noyyal and Bhavani.Tamil Nadu, a South Indian state, is famed for its Dravidian-style Hindu temples.The three ancient Tamil empires of Chera, Chola, and Pandya were of ancient origins.In Tamil Nadu, the Neolithic period had its advent around 2500 BCE

Districts of Tamil Nadu

1. Chennai
2. Coimbatore
3. Salem
4. Sivaganga
5. Cuddalore
6. Thanjavur
7. Dharmapuri
8. Nilgiris
9. Dindigul
10. Theni
11. Erode
12. Ariyalur
13. Pudukkottai
14. Tiruppur
15. Thoothukudi
16. Kanchipuram
17. Chengalpattu
18. Kallakurichi
19. Tiruchirappalli
20. Kanyakumari
21. Tirunelveli
22. Tenkasi
23. Karur
24. Tiruvallur
25. Krishnagiri
26. Tiruvannamalai
27. Madurai
28. Thiruvarur
29. Nagapattinam
30. Vellore
31. Ranipet
32. Tirupathur
33. Namakkal
34. Viluppuram
35. Perambalur
36. Virudhunagar
37. Ramanathapuram.
38. Mayiladurthurai

Computer Memory

           A memory is just like a human brain. It is used to store data and instructions. Computer memory is the storage space in the computer, where data is to be processed and instructions required for processing are stored. The memory is divided into large number of small parts called cells. Each location or cell has a unique address, which varies from zero to memory size minus one. For example, if the computer has 64k words, then this memory unit has 64 * 1024 = 65536 memory locations. The address of these locations varies from 0 to 65535.

Memory is primarily of three types −

• Cache Memory
• Primary Memory/Main Memory
• Secondary Memory

Cache Memory

Cache memory is a very high speed semiconductor memory which can speed up the CPU. It acts as a buffer between the CPU and the main memory. It is used to hold those parts of data and program which are most frequently used by the CPU. The parts of data and programs are transferred from the disk to cache memory by the operating system, from where the CPU can access them.

The advantages of cache memory are as follows −

• Cache memory is faster than main memory.
• It consumes less access time as compared to main memory.
• It stores the program that can be executed within a short period of time.
• It stores data for temporary use.

Disadvantages

The disadvantages of cache memory are as follows −

• Cache memory has limited capacity.
• It is very expensive.

Primary Memory (Main Memory)

Primary memory holds only those data and instructions on which the computer is currently working. It has a limited capacity and data is lost when power is switched off. It is generally made up of semiconductor device. These memories are not as fast as registers. The data and instruction required to be processed resides in the main memory. It is divided into two subcategories RAM and ROM.

Characteristics of Main Memory

• These are semiconductor memories.
• It is known as the main memory.
• Usually volatile memory.
• Data is lost in case power is switched off.
• It is the working memory of the computer.
• Faster than secondary memories.

     A computer cannot run without the primary memory

Secondary Memory

This type of memory is also known as external memory or non-volatile. It is slower than the main memory. These are used for storing data/information permanently. CPU directly does not access these memories, instead they are accessed via input-output routines. The contents of secondary memories are first transferred to the main memory, and then the CPU can access it. For example, disk, CD-ROM, DVD, etc.

Characteristics of Secondary Memory

• These are magnetic and optical memories.
• It is known as the backup memory.
• It is a non-volatile memory.
• Data is permanently stored even if power is switched off.
• It is used for storage of data in a computer.
• Computer may run without the secondary memory.
• Slower than primary memories.

 

Software

 

Software •

“A set of instructions given to the computer to solve a problem is called Software.” 

• “Software is a single/collection of programs that performs a particular task.”

 •Software is also called Program.

 • Different software's are used to solve different problems

Types of Software

Software can be divided into two major categories.

1. System Software.
2. Application Software.

System Software       

         System Software is set of programs to control and manage the operations of a computer hardware.

  • It enables application programs to execute properly

. • It consists of the basic operations as follows: ▫ Saving data on disk

  ▫ Making computer to work for us 

  ▫ Printing a document etc. 

         

Operating system

The operating system is system software that manages computer hardware, software resources, and provides common services for the computer program. It works as an interface between the user and computer hardware. system software is an intermediator or a middle layer between the user and the hardware. 

  Examples

        Windows 98

        Windows 2000

        Windows XP

        Windows 7

        Windows 10

        Linux

        Unix

Device Driver

 • A Device Driver is a computer program that operates or controls a particular type of device that is attached to a computer.

 ▫ printer drivers

Utility program 

• Utility program is a system software that allows a user to analyze, configure and Maintain the computer.

 • It performs a specific task related to the management of computer

Exambles

Antivirus.

Application Software

       • Application Software includes programs that do real work for user.

     • Application Software is created to perform specific tasks for a user

   . • It is also known as application package.

     • Application software is used to perform various applications on the computer. 

        Examples

        Microsoft office

        Photoshop

Computer Generations

 

FIRST GENERATION

• Introduction:
  1. 1946-1959 is the period of first generation computer.
  2. J.P.Eckert and J.W.Mauchy invented the first successful electronic computer called ENIAC, ENIAC stands for “Electronic Numeric Integrated And Calculator”.
• Few Examples are:
  1. ENIAC
  2. EDVAC
  3. UNIVAC
  4. IBM-701
  5. IBM-650

  …

• Advantages:
  1. It made use of vacuum tubes which are the only electronic component available during those days.
  2. These computers could calculate in milliseconds.
• Disadvantages:
1. These were very big in size, weight was about 30 tones.
2. These computers were based on vacuum tubes.
3. These computers were very costly.
4. It could store only a small amount of information due to the presence of magnetic drums.
5. As the invention of first generation computers involves vacuum tubes, so another disadvantage of these computers was, vacuum tubes require a large cooling system.
6. Very less work efficiency.
7. Limited programming capabilities and punch cards were used to take inputs.
8. Large amount of energy consumption.
9. Not reliable and constant maintenance is required
1. 
   
   
   
   

SECOND GENERATION

• Introduction:
  1. 1959-1965 is the period of second-generation computer.
  2. 3.Second generation computers were based on Transistor instead of vacuum tubes.
• Few Examples are:
  1. Honeywell 400
  2. IBM 7094
  3. CDC 1604
  4. CDC 3600
  5. UNIVAC 1108

  … many more

• Advantages:
  1. Due to the presence of transistors instead of vacuum tubes, the size of electron component decreased. This resulted in reducing the size of a computer as compared to first generation computers.
  2. Less energy and not produce as much heat as the first genration.
  3. Assembly language and punch cards were used for input.
  4. Low cost than first generation computers.
  5. Better speed, calculate data in microseconds.
  6. Better portability as compared to first generation
• Disadvantages:
1. A cooling system was required.
2. Constant maintenance was required.
3. Only used for specific purposes.
1. 
   
   
   
   

THIRD GENERATION

• Introduction:
  1. 1965-1971 is the period of third generation computer.
  2. These computers were based on Integrated circuits.
  3. IC was invented by Robert Noyce and Jack Kilby In 1958-1959.
  4. IC was a single component containing number of transistors.
• Few Examples are:
  1. PDP-8
  2. PDP-11
  3. ICL 2900
  4. IBM 360
  5. IBM 370

  … and many more

• Advantages:
  1. These computers were cheaper as compared to second-generation computers.
  2. They were fast and reliable.
  3. Use of IC in the computer provides the small size of the computer.
  4. IC not only reduce the size of the computer but it also improves the performance of the computer as compared to previous computers.
  5. This generation of computers has big storage capacity.
  6. Instead of punch cards, mouse and keyboard are used for input.
  7. They used an operating system for better resource management and used the concept of time-sharing and multiple programming.
  8. These computers reduce the computational time from microseconds to nanoseconds.
• Disadvantages:
  1. IC chips are difficult to maintain.
  2. The highly sophisticated technology required for the manufacturing of IC chips.
  3. Air conditioning is required.





1. 
   

FOURTH GENERATION

• Introduction:
  1. 1971-1980 is the period of fourth generation computer.
  2. This technology is based on Microprocessor.
  3. A microprocessor is used in a computer for any logical and arithmetic function to be performed in any program.
  4. Graphics User Interface (GUI) technology was exploited to offer more comfort to users.
• Few Examples are:
  1. IBM 4341
  2. DEC 10
  3. STAR 1000
  4. PUP 11

  … and many more

• Advantages:
  1. Fastest in computation and size get reduced as compared to the previous generation of computer.
  2. Heat generated is negligible.
  3. Small in size as compared to previous generation computers.
  4. Less maintenance is required.
  5. All types of high-level language can be used in this type of computers.
• Disadvantages:
  1. The Microprocessor design and fabrication are very complex.
  2. Air conditioning is required in many cases due to the presence of ICs.
  3. Advance technology is required to make the ICs.











FIFTH GENERATION

• Introduction:
  1. The period of the fifth generation in 1980-onwards.
  2. This generation is based on artificial intelligence.
  3. The aim of the fifth generation is to make a device which could respond to natural language input and are capable of learning and self-organization.
  4. This generation is based on ULSI(Ultra Large Scale Integration) technology resulting in the production of microprocessor chips having ten million electronic component.
• Few Examples are:
  1. Desktop
  2. Laptop
  3. NoteBook
  4. UltraBook
  5. Chromebook

  … and many more

• Advantages:
  1. It is more reliable and works faster.
  2. It is available in different sizes and unique features.
  3. It provides computers with more user-friendly interfaces with multimedia features.
• Disadvantages:
1. They need very low-level languages.
2. They may make the human brains dull and doomed.
1.