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July 31, 2013
- Committee Stage: A specially important measure usually goes to a Select Committee or Joint Committee which is expected to give its report within a specified period.
- Report Stage : After submission of the report by the committee, Members can send in their amendments to the different provisions of the Bill.
- Each clause is taken up by the House and amendments are moved, discussed and disposed of.
- When the clause by clause consideration is over and every clause is voted, the second reading of the Bill is over.
A vision statement is .....
not required for established companies
not required due to competition
not required as no one understands them
a long term inspiration
Non-product selling means .....
selling variety of products
selling only one product
selling seasonal products
Marketing is a function undertaken by ......
All front-office staff
All of these
July 30, 2013
- To avoid classroom hunger
- To increase school enrolment
- To increase school attendance
- To reduce gender gap
- To foster social equality
- To address malnutrition
- To promote community participation
- Women empowerment
July 29, 2013
- Allocation of foodgrains (rice & wheat) to these AAY families is made @ 35 kg per family per month at a highly subsidized Central Issue Price (CIP) of Rs.2 per kg for wheat and Rs.3 per kg for rice.
- The scale of issue that was initially 25 kg per family per month has been increased to 35 kg per family per month with effect from 1st April, 2002.
- On whole India there are 2.43 crore Antyodaya Anna Yojna beneficiary households will continue to get their quota of 35 kg grains a month under the TPDS.
- Coverage under this scheme has been expanded thrice since then i.e. during 2003-04, 2004-05 and 2005-06 covering additional 50 lakh households each time
- Thus the total coverage under AAY was raised to 2.50 crore AAY families. The identification of AAY families within the target of AAY families allocated to each State/UT is the responsibility of concerned State/UT Government.
- Upto March, 2013, they have reported issuance of AAY ration cards to 2.43 crore AAY families
It first surfaced last year as "human betacoronavirus 2c EMC", but the suffixes "2c England-Qatar, "2C Jordan-N3", "England 1" have also appeared and many scientists have resorted to "novel coronavirus" - new crown-shaped virus - instead.
The infection has now emerged as a serious cause for concern, especially in India, as thousands are set to travel to Saudi Arabia in the coming days for Umrah and Haj. Emerging evidence suggests Saudi Arabia as the apparent geographic hub of the novel corona virus.
- Japan and
- the U.S.
July 27, 2013
July 26, 2013
July 25, 2013
- The first hour of every sitting of Lok Sabha is called the Question hour.
- Asking of questions in Parliament is the free and unfettered right of members.
- It is during the Question hour that they may ask questions on different aspects of administration and Government policy in the national as well as international spheres.
- Every Minister whose turn it is to answer to questions has to stand up and answer for his Ministry's acts of omission or commission.
Observers (Engineering) in AP Research Labs (Exam Held on 23-06-2013) - General Studies Papers Solved APPSC
July 23, 2013
- Gaekwad of Baroda
- Raghuji Bhonsle of Nagpur,
- Malhar Rao Holkar of Indore and
- Ranaji Scindia of Gwalior.
Peshwa Baji Rao organized them into one union known as the confederacy and allowed them to levy the taxes and to enjoy the maximum autonomy. But they had to pay the share of the state income and work under the Peshwa and are also required to join the Peshwa in military campaign against the common enemy.
July 22, 2013
July 21, 2013
- Bills originating in Rajya Sabha which are still pending in that House do not lapse.
- Bills originating in Rajya Sabha which having been passed by the House and send to Lok Sabha and pending there lapse on the dissolution of Lok Sabha. i.e Bill becomes invalid.
- Bills originating in Lok Sabha which having been passed by that House and transmitted to Rajya Sabha and still pending there on the date of dissolution of Lok Sabha, lapse.
- Bills originating in Rajya Sabha and returned to that House by Lok Sabha with amendments and still pending there on the date of its dissolution, lapse.
- A Bill upon which the Houses have disagreed and the President has notified his intention to summon a Joint Sitting of the Houses to consider the Bill prior to dissolution does not lapse on dissolution.
- Select/Joint Committees on Bills constituted by the House(s) on specific motion to consider and report on Bills; and
- Committees which are constituted from time to time to enquire into and report on specific subjects.
- Highest temperature noted during a day is called Maximum Temperature while lowest temperature noted during a day is called Minimum Temperature. The average of daily Maximum and Minimum temperature is called the Daily Mean Temperature.
- For finding out the maximum and the minimum temperature of air the weather instrument that is used is called Six's Thermometer. Temperature is measured in degrees of Celsius or Fahrenheit.
- It is measured by Aneroid Barometer and the units -Millibars.
- Tempertaure is inversely proportional to Pressure.
- A quantity of 10 Kgs. of food grains (rice) is provided per month free of cost to the beneficiaries covered under the scheme.
- The beneficiaries were identified during Grama Sabha
- Male or female should be 65years or above.
- The applicant should be a “destitute” in the sense of having little or no regular means of subsistence from his/her own source of income or through financial support from family members or other sources.
- Funds are currently released to the State Departments of Food & Civil Supplies (F&CS;) in one instalment This Department then ties up with the Food Corporation of India (FCI), to release foodgrains districtwise on payment of the cost of Foodgrains at CIP rates directly to the FCI offices.
1. A (n) program is one that is ready to run and does not need to be altered in any way.
July 20, 2013
>>Direct Download PDF Link Here: Download <<<
Group 1 is the highest cadre recruited by APPSC.
- The various posts which come under APPSC Group 1, their pay scale, reservation details and education qualification required for various posts under Group 1 should be read if aspirant is just beginner in preparation to the exam. (Various Posts, Eligibility & Pay scale to different Group 1 Cadre Posts)
- This exam is a three stage exams( Download Pattern and Syllabus of Group 1 from here).
- Dont ignore the reference books to be read for APPSC Group 1, leaving it will end you no where.( Reference books for APPSC Group 1 Exams)
- Students often ask about of Group 1 prelims, as clearing prelims is important stage, aspirants should know cutoff's of various years Group 1 (APPSC Group 1 Exam Cutoff Marks Analysis)
- Many students often confuse in which language to be written in Mains exam, if you are in such dilemma you should definitely read (In which language APPSC Group 1 Mains can be written?)
- You Might be questioning yourself as how much score will be needed to successfully cross the mains stage and appear for Group 1 Mains Interview. (Group 1 Mains Marks Analysis!)
Aspirants often confuse with a question- How should I start my preparation for Group 1???
Group 2 is the second highest cadre. Its a two stage exam for Executive Posts & One stage Exam for Non -Executive Posts.
- Article on Job profiles & Promotional aspects of various Group 2 Posts are worth sparing time, as it will give you an idea, where your are heading.
- Group 2 exam is held in 3 papers, readers may browse this link to know pattern and Syllabus in Telugu Medium.
- Recently Government has issued G.O relating to merger of Group 1 & Group 2 Executive Posts. If merger happens how will APPSC Group 1 Look????
Last but not least, Some important preparation tips which aspirants should keep in mind while preparing for civil service exams.
July 19, 2013
July 18, 2013
- The Union government’s initiative to control anaemia comes in with the report of National Health and Family Welfare Survey III and the National Nutrition Monitoring Bureau study which has reported the prevalence of anaemia among adolescents with a haemoglobin value of under 12 grams percentage in girls and haemoglobin value of under 13 grams percentage in boys. Anaemia is seen a serious public issue as around 74 per cent of the population have their haemoglobin level less than the normal level.
- It is estimated that over 56 per cent of the adolescent girls and 30 per cent of the boys in the same age group of 10 to 19 years are anaemic in India.
- Almost 50 per cent of nutritional deficiency-related anaemia is Iron Deficiency Anaemia which is a result of under-nutrition and poor dietary intake of iron
July 17, 2013
July 16, 2013
- As much as candidate practice; his/her speed, accuracy and time limit to solve a particular section will increase day by day.
- The right understanding of the problem can help the aspirants to sail through this section.
- Problems on Ages
- Problems on
- HCM and LCM of
- Square and Cube
- Surds and
- Ratio &
- Chain Rule
- Profit and Loss
- Time and Work
- Time and
- Boats and
- Alligations and
- Simple Interest
- True Discount
- Bankers Discount
- Clocks and Calendar
- Mean, Mode and
- Permutations and
Combinations Part 1
- Permutations and
Combinations Part 2
Definition : A Computer is an electronic device that can perform activities that involve Mathematical, Logical and graphical manipulations. Generally, the term is used to describe a collection of devices that function together as a system.
It performs the following three operations in sequence.
1. It receives data & instructions from the input device.
2. Processes the data as per instructions.
3. Provides the result (output) in a desired form.
Data : It is the collection of raw facts, figures & symbols.
Ex : Names of students and their marks in different subjects listed in random order.
Information : It is the data that is processed & presented in an organized manner.
Ex : When the names of students are arranged in alphabetical order, total and average marks are calculated & presented in a tabular form, it is information.
Program : Set of instructions that enables a computer to perform a given task.
Advantages of computers :
1. High speed : Computers have the ability to perform routine tasks at a greater speed than human beings. They can perform millions of calculations in seconds.
2. Accuracy : Computers are used to perform tasks in a way that ensures accuracy.
3. Storage : Computers can store large amount of information. Any item of data or any instruction stored in the memory can be retrieved by the computer at lightning speeds.
4. Automation : Computers can be instructed to perform complex tasks automatically ( which increases the productivity).
5. Diligence : Computers can perform the same task repeatedly & with the same accuracy without getting tired.
6. Versatility : Computers are flexible to perform both simple and complex tasks.
7. Cost effectiveness : Computers reduce the amount of paper work and human effort, thereby reducing costs.
Limitations of computers :
1. Computers need clear & complete instructions to perform a task accurately. If the instructions are not clear & complete, the computer will not produce the required result.
2. Computers cannot think.
3. Computers cannot learn by experience.
Generations of computers :
Integrated Circuits (IC)
Very Large Scale Integrated Circuits
(1980 – till today )
Ultra Scale Integrated Circuits (ULSI)
Micro Processor (SILICON CHIP)
ANATOMY OF COMPUTERS
The computer system consists of three units:
1. Input device 2. Central Processing Unit (CPU) 3. Output device
1.Input device : Reads information from input media and enters to the computer in a coded form
(a) Memory unit : Stores program and data
(b) Arithmetic Logic unit : Performs arithmetic and logical functions
(c) Control Unit : Interprets program instructions and controls the input and output devices
3. Output device : decodes information and presents it to the user
Central Processing Unit: It is the part of the computer that carries out the instructions of a computer program. It is the unit that reads and executes program instructions. Hence it is known as the
―brain‖ of the computer. The CPU consists of storage or memory unit, Arithmetic Logic Unit (ALU)
and control unit.
(a). Memory Unit: It is also known as the primary storage or main memory. It stores data, program instructions, internal results and final output temporarily before it is sent to an appropriate output device. It consists of thousands of cells called ―storage locations‖. These cells activate with ―off-on‖ or binary digits(0,1) mechanism. Thus a character either a letter or numerical digit is stored as a string of (0,1) Binary digits ( BITS). These bits are used to store instructions and data by their combinations.
(b) Arithmetic and Logical Unit(ALU): It is the unit where all Arithmetic operations (addition, subtraction etc.) and logical functions such as true or false, male or female are performed. Once data are fed into the main memory from input devices, they are held and transferred as needed to ALU where
processing takes place. No process occurs in primary storage. Intermediate generated results in ALU are temporarily placed in memory until needed at later time. Data may move from primary memory to
ALU and back again to storage many times before the process is finalized.
(c).Control Unit : It acts as a central nervous system and ensures that the information is stored correctly and the program instructions are followed in proper sequence as well as the data are selected from the memory as necessary. It also coordinates all the input and output devices of a system .
Devices used to provide data and instructions to the computer are called Input devices. Some important input devices are
Key board, Mouse, Scanner, MICR, Web camera, Microphone etc.
1. Keyboard: The Key board is used for typing text into the computer. It is also known as standard Input device. A computer keyboard is similar to that of a type writer with additional keys. The most commonly available computer keyboard has 104 keys.
There are different types of keys on the keyboard. The keys are categorized as :
· Alphanumeric keys , including letters & numbers.
· Punctuation keys, such as colon (:), semicolon (;) Question mark (?), Single & double quotes
· Special keys such as arrow keys, control keys, function keys (F1 to F12), HOME, END etc.
2 Mouse: It is a device that controls the movement of the cursor on a monitor. A mouse will have 2 buttons on its top. The left button is the most frequently used button. There will be a wheel between the left and right buttons. This wheel enables us to smoothly scroll through screens of information. As we move the mouse, the pointer on the monitor moves in the same direction. Optical mouse is another advanced pointing device that uses a light emitting component instead of the mouse ball. Mouse cannot be used for entering the data. It is only useful to select the options on the screen.
3. Scanner:It is an input device that can read text or illustrations printed on paper and translate into digital form. The main advantage of these scanners is that the data need not be entered separately
resulting in saving lot of time.
Scanners are of two types: i) optical scanners ii) MICR
i) Optical scanners:
a. Optical character Recognition(OCR): In this, characters are read with the help of a light. This is used in office atomization, documentation in library etc.
b. Optical mark recognition(OMR): It is a technology where an OMR device senses the presence or absence of a mark such as a pencil mark. OMR is used in tests such as aptitude tests.
c. Optical barcode recognition(OBCR): Barcode readers are photoelectric scanners that read the bar codes or vertical zebra striped marks printed on product containers. This is used in super markets, book shops etc.
ii. MICR: This is widely used in banks to process the cheques. This allows the computer to recognize characters printed using magnetic ink.
4. Magnetic Ink Character Recognition(MICR): : It is a character recognition technology used primarily by the banking industry to facilitate the processing of the cheques. MICR characters ( cheque No., Acc.No.etc) are printed in special ink usually containing iron oxide. When a document that contains the ink needs to be read, it passes through a machine which magnetizes the ink and there will be a reader sorter unit which translates the magnetic information into characters. MICR provides a secure, high speed of scanning and processing information. It scans about 2600 cheques/min.
Any device that is capable of representing information on a computer is called an Output device. Output devices receive information from the CPU and present it to the user in the desired form.
Some important Output devices are : Monitor, Printer
1 .Terminal/Monitor: It is similar to TV screen- either a monochrome (black & white) or colour – and it displays the output. It is also referred as Visual Display Unit(VDU). Several types of monitors are in use. Some of them are Colour Graphic Adapter(CGA), Enhanced Graphics Adaptor(EGA) , Video Graphics Adapter (VGA) and Super Video Graphics Adapter (SVGA).
The screen sizes differ from system to system. The standard size is 24 lines by 80 characters. Most systems have provision for scrolling which helps in moving the text vertically or horizontally on the screen.
2 . Printer: A printer is used to transfer data from a computer onto paper. The paper copy obtained
from a printer is often referred as ―printout‖. The different printers and their speeds are as follows:
Mode of Printing
Dot – Matrix
Prints the character in dotted pattern
through printer ribbon using either 24 pin or 9 pin
200/300 to 700
Ink Jet printer
Work by spraying ionized ink
Slow, 90 CPS
Also called page printer. Uses laser
beam to produce an image.
6 to 12 PPM
Prints lines at a time instead of single
300 to 600 LPM
Produces drawings or graphs through
pens which are filled with different colours.
( CPS: Characters Per Second; PPM: Pages Per Minutes; LPM : Lines Per Minute)
MEMORY OF THE COMPUTER
Memory or storage capacity is one of the important components of a computer. Any storage unit of a computer system is classified on the basis of the following criteria:
1. Access time: This is the time required to locate and retrieve stored data from the storage unit in response to program instructions.
2. Storage capacity: It is the amount of data that can be stored in the storage unit.
3. Cost per bit of storage.
Units of memory: The computer stores a character in the storage cells with binary (0,1) mechanism. Thus the basic unit of memory is a bit (binary digit – 0,1). To store a character, a computer requires 8 bits or 1 byte. This is called the ― word length‖ of the storage unit. Hence the storage capacity of the computer is measured in the number of words it can store and is expressed in terms of bytes. The different units of measurement are
8 Bits = 1 Byte
210 (or) 1024 Bytes = 1 Kilo Byte (KB)
210 (or)1024 KB = 1 Mega Byte (MB)
210 (or)1024 MB = 1 Gega Byte (GB) Conversion :
ASCII – American Standard Code for Information Interchange.This code has given alphabets like some numbers which can be converted to Binary form. A- 65 …….Z – 90 and a – 97 ………. z – 121
By using these codes the alphabets can be converted to digital & hence to Binary form.
Types of Memory : A computer memory is of two types
1. Primary Memory ( Internal storage) 2. Secondary Memory ( External storage)
Primary Memory : Primary memory is also called internal memory and is an important part of a computer. It is the main area in a computer where the data is stored. The stored data can be recalled instantly and correctly whenever desired. This memory can be quickly accessed by the CPU for reading or storing information. Primary memory is further classified into two types:
Random Access Memory (RAM) and Read- Only Memory (ROM ) RAM:
RAM is also known as read/write memory as information can be read from and written onto it. RAM is a place in a computer that holds instructions for the computer, its programs and the data. The CPU can directly access the data from RAM almost immediately. However, the storage of data and instructions in RAM is temporary, till the time the computer is running. It disappears from RAM as soon as the power to the computer is switched off. i.e it is volatile memory.
ROM:It is called Read-only memory as information can only be read from and not written or changed onto ROM. ROM is the ‗built-in' memory of a computer. It stores some basic input – output instructions put by the manufacturer to operate the computer. The storage of data and instructions in ROM is permanent. It does not depend on the power supply. i.e it is non-volatile memory.
Secondary memory: The primary memory which is faster (and hence expensive) is generally not sufficient for large storage of data. As a result, additional memory, called the ―auxiliary‖ or ―secondary memory‖ is used. It is also referred as ―backup storage‖ as it is used to store large volume of data on a permanent basis which can be transferred to the primary memory whenever required for processing. Data are stored in secondary storage in the same binary codes as in the main (primary memory) storage. Some of the devices of secondary storages are Floppy Disk, Hard Disk, CD-ROM, DVD and Flash drive.
1. Floppy Disk: It is also referred as ―Diskette: and is made of flexible Vinyl material. It has a small hole on one side called ―Right protect notch‖, Which protects accidental writing/deleting the information from the disk. There is a hole in the centre through which the spindle of drive unit rotates the disk. The disks are available in two sizes of 5.25 and 3.5 inches and these could be either low- density or high-density floppies. Storage capacity of floppies are measured in kilobytes (KB) and
megabytes (MB). The details about the storage capacities of the floppies are presented below:
2. Hard Disk: The hard disk can hold more information than the floppy disk and the retrieval of information from hard disk is faster when compared to floppies or tapes. A hard disk is fixed inside the CPU and its capacity ranges from 20 MB onwards. The hard disk is made up of a collection of discs (one below the other) known as platters on which the data is recorded. These platters are coated with magnetic material. It is less sensitive to external environmental disorders and hence the storage in hard disk is safe. A small hard disk might be as much as 25 times larger than a floppy disk. Storage Capacity of hard disks varies from 20 MB to several Gega bytes like 80GB, 160GB.
3. CD-ROM: CD-ROM stands for Compact Disk–Read Only Memory. It is used to store a wide variety of information. Its main advantage is that it is portable and can hold a large amount of data.. The storage capacity of most CD-ROMs is approximately 650 MB or 700 MB.
CD-ROMs have the following variations:
(i) CD-R(Compact disc Recordable): Data can be written onto it just once. The stored data can be read. Data once written onto it cannot be erased.
(ii) CD-RW(Compact disc Rewritable): It is also called erasable CD. Data once written onto it can be erased to write or record new information many times.To use a CD-ROM, a device called CD drive is needed.
4. DVD: DVD stands for Digital Versatile Disc. It is similar to a CD-ROM, except that it can store larger amounts of data. The storage capacity of a DVD is at least 4.7MB. DVDs that can store up to
17GBs are also available. Because of their capacity, DVDs are generally used to store a very large multimedia presentations and movies that combine high quality sound and graphics.
5. Flash Drive: It is a small, portable device that can be used to store, access and transfer data. Due to its small size, it is commonly called Pen drive. It is also called USB drive. We can read, write, copy, delete, and move data from computer to pen drive or pen drive to computer. It comes in various storage capacities of 2GB, 4GB, 8GB etc. It is popular because it is easy to use and small enough to be carried in a pocket. This device is plugged into the USB port of the computer and the computer automatically detects this device.
HARDWARE and SOFTWARE
Hardware: The physical components of the computer are known as ―Hardware‖. It refers to the objects that we can actually touch.
Ex: input and output devices, processors, circuits and the cables.
Software: Software is a program or set of instructions that causes the Hardware to function in a desired way. The basic difference between the Hardware and Software is just the same as that exists between TV and TV studio. Without TV studio (software) from where the programs are telecast, the TV (Hardware) is a dead machine.
There are five categories of software. They are:
1. Operating System 2. Translators 3. Utility programs 4. Application programs
5. General purpose programs
1. Operating System (OS) : The software that manages the resources of a computer system and schedules its operation is called Operating system. The operating system acts as interface between the hardware and the user programs and facilitates the execution of programs.
Generally the OS acts as an interface between the user and the Hardware of the computer. i.e It is a bridge between the user and the Hardware.
The User interface provided by the OS can be character based or graphical.
CUI -- Character user Interface
GUI -- Graphical user Interface
CUI : It is operated with keyboard only. Ex: MS-DOS, UNIX
GUI : The system can be operated with mouse and keyboard. Ex: Windows 95, Windows XP etc
· Disk Operating System (DOS): It was developed as early as 1980 by Bill Gates at the age of 19. It is suited for personal computers. Dos is a single user and single task operating system
· WINDOWS : It works with DOS and it supports single user and multitask system. It requires a powerful PC with a minimum RAM of 8 MB .
· UNIX AND XENIX: It is suited for multi-user and multi-task system
2. Translators : Computers can understand instructions only when they are written in their own language – the machine language . Therefore, a program written in any other language should be translated into machine language. The software that ―translates‖ the instructions of different languages is known as translators .
There are two types of translators. They are compilers and Interpreters
A Compiler checks the entire user – written program (known as the source program) and if it is error free, produces a complete program in machine language (known as object program). The source program is retained for possible modifications and corrections and the object program is loaded into the computer for execution. If the source program contains errors, the compilers produce a list of errors at the end of the execution of the program. i.e a compiler translates the whole program before execution. An interpreter does a similar job but in a different style. The interpreter translates one statement at a time and if it is error – free, executes. This continues till the last statement. Thus an interpreter translates or executes the first instruction before it goes to the second, while a compiler translates the whole program before execution.
The major difference between compiler and interpreter is
1. Error correction is very much simpler in the case of interpreter as it translates the statements in stages. The compiler produces an error list of the entire program at the end.
2. Interpreter takes more time for the execution of the program compared to compilers as it translates one statement at a time
Programming Languages: There are three types of programming languages.
1. Machine Languages: Computers respond only to machine language. This language is in terms of binary codes (0,1). i.e. all programs should be written with these codes, which is difficult, time consuming and leading to errors while writing the programs. There is no unique standard machine language. Rather there are many machine languages. These are machine dependent. These are referred as the first generation languages.
2. Assembly Languages : It uses mnemonic codes rather than numeric codes (as in machine languages). Ex. Add or A is used as a symbol for addition. It requires translators to convert into machine language. Like machine language, writing program in assembly language is also time consuming. These are also machine dependent.
3. High Level Languages (HLL): These are referred as problem oriented languages (POL). These are referred as third generation languages. The advantages of these languages are
· The high level languages are convenient for writing programs as they can be written without any codes. These languages follow rules like ―Englishlanguage.
· Because of their English like nature, less time is required to write a program.
· They are machine independent. A program written in any HLL can be run on computers of different types without any modifications.
Several High Level Languages which are in common use:
- FORTRAN : FORmula TRANslation
- COBOL : Common Business Oriented Language
- BASIC : Beginner's All purpose Symbolic Instruction Code
- PROLOG: PROgramming in LOGic
- ALGOL : ALGOrithmic Language
3. Utility Programs: These are pre-written programs supplied by the manufacturer for maintaining day to day activities of computer system.
Example: COPY, SORT, MAILING, virus scanning software etc.,
4. Application Programs: These are user written programs to do a specific job which can be changed to meet the individual needs. These programs are written in different languages such as BASIC or C or by using database packages like dBASE, Oracle. Example: Payroll, Billing, Railway Reservation etc.
5. General Purpose Packages: These packages are developed to suit the needs of research workers / scientists in different fields. These packages are categorized as :
i) Data Analysis ii) Word Processing iii) Spread Sheet iv) Graphics and v) Databases
Ex: SPSS (Statistical Package for Social Science), MSTAT, MICROSTAT, GENSTAT, SAS etc.
Ex: WORD PERFECT, WORDSTAR, MS-Word, CHIRATOR, NORTON EDITOR etc.
Ex: LOTUS, Qpro, VP-PLANNER, SYMPHONY, MS-Excel etc.
Ex: LOTUS, STORY-BOARD, POWER-POINT etc.
Ex: dBASE, FOX-BASE, FOX-PRO, ORACLE, MS-Access etc.
Functions of Operating System : Today most operating systems perform the following important functions :
1. Processor management : It manages the assignment of processor to different tasks being performed by the computer system.
2. Memory management : It manages the allocation of main memory and other storage areas to the system programmes as well as user programmes and data.
3. Input / Output management : It manages the co-ordination and assignment of different Input and Output devices while one or more programmes are executed.
4. File management : It allows all files to be easily changed and modified through the use of text editors or some other file manipulation routines.
5. Establishment and enforcement of a priority system : It determines and maintains the order in which jobs are to be executed in the computer system.
6. Interpretation of commands and instructions.
7. Facilitates easy communication between the computer system and the computer operator.
Classification of Computers
Computers are classified according to the storage capacity, speed and the purpose for which they are developed. These can be classified into three types:
1. Analog Computes 2. Digital Computers 3. Hybrid Computers
1. Analog computers: They operate by ―measuring‖ instead of ―counting‖. The name (derived from greek word analog) denotes that the computer functions by establishing similarities between the two quantities. They are powerful tools for solving differential equations.
2. Digital Computers: These computers operate by ―counting‖. All quantities are expressed as discrete digits or numbers. These are useful for evaluating arithmetic expressions and manipulations of data.
3. Hybrid Computers: Computers which combine the features of analog and digital computers are known as Hybrid computers.
A majority of the computers that are in use are digital. These computers were essentially developed for computations. Later, the developments in the computers led to the use of digital computers in variety of applications. Depending on the use of applications, the digital computers are classified into 1) Special Purpose Computers and 2) General Purpose Computers
1. Special Purpose Computers: These are developed with a specific purpose. Some of the areas where these computers are being used are – soil testing, drip irrigation, medical scanning, traffic signals, spacecraft, rocket technology etc.,
2. General Purpose Computers: These are developed to meet the requirements of several areas such as simulation, solving mathematical equations, payroll and personnel database. These computers are available in different sizes and capabilities and are further classified (based on memory, speed, storage) as follows.
a) Super Computers b) Mainframe Computers c) Mini Computers d) Micro Computers
a) Super Computers: These have extremely large storage capacities and computing speeds which are atleast 10 times faster than other computers. These are used for large scale numerical problems in scientific and engineering disciplines such as electronics, weather forecasting etc.,. The first super computer was developed in U.S.A. by CRAY computers. In India the indigenous super computer was developed under the name Param.
b) Mainframe Computers: They also have large storage and high computing speed (but relatively lower than the super computers). They are used in applications like weather forecasting, space applications etc., they support a large number of terminals for use by a variety of users simultaneously, but are expensive
c) Mini Computers: It is a medium sized computer with moderate cost, available indigenously and used for large volume applications. It can serve multi-users simultaneously
d) Micro Computers: A micro computer is the smallest general purpose processing system.Micro computers are also referred as ―personal computers‖(PC). These are self contained units and usually developed for use by one person at a time but can be linked to very large systems. They are cheap, easy to use even at homes and can be read for variety of applications from small to medium range. These are available in three models:
1. PC : Personal Computer
2. PC-XT : PC with Extended Technology
3. PC-AT : PC with Advanced Technology