Previous year UPSC Question papers collection (PDF)

Students preparing for any UPSC exam should not restrict them to refer question papers of their exam alone. Here is the complete collection of UPSC exam question papers since 2009. This collection will be extremely useful for the preparation of civil service exam.

Question papers that are useful for the preparation of CSP, 2015

Practicing many mock tests is the crucial step in the preparation of high level exam such as civil service exam. Previous year question papers is a never miss asset for every serious civil service aspirants. I have complied more than 80 objective type UPSC questions papers into a single RAR file and i hope they will be highly useful during the Civil service preliminary exam preparation.

How to use this collection effectively for CSP preparation?

SCRA and STENOGRAPHER question papers have HSC level syllabus. Believe it or not. 25% of the CSP questions are of HSC level. So even lower exam exam helps you in your preparation. Other exam question papers provided in the collection is of Degree level and so they are directly useful in your civil service preparation. Download link of the collection is given below.

Collection of UPSC question papers since 2009  (Size: 122 MB)

Note: This collection does not contain specialized exam papers such as Medicine, Maths, Engineering, Economics, etc. In other words this collection has only General studies and Aptitude question papers.

Exam wise Question paper collection:

Following section has individual collection for all important UPSC exams.

1. SCRA (9.75 MB)

2. CDS (26.5 MB)

3. NDA (17.0 MB)

4. Stenographer (9.61 MB)

5.CAPF (4.67 MB)

6.CISF (3.49 MB)

7. Civil service exam (68.4 MB)

Question paper collection for Civil service Mains will be posted soon


Computing abbreviation part 2

FIFO: First in first out is a queue model in which service is offered on first come first serve basis. Classical example of FIFO is traditional railway ticket booking in the counter.

FTP: File transfer protocol is a network protocol for transferring files from one computer to another computer over TCP/IP based network.

GIF: Graphic Interchange Format is a image format and this format supports animations.

GPRS: General packet radio service is a data transfer service for GSM enabled mobile phoned.

GSM: Global system of Mobile communication is commonly used mobile standard for 2G mobile technology.

GUI: Graphic user interface is a interactive interface that enables user to interact with any electronic device by the means of icons and dialog box. GUI was initially introduced in computers and it is extended to almost all electronic devices. Traditional computer’s interface was command based interface but GUI superseded it.

HTML: Hypertext mark up language is a programming language that is used to design a web page. (For more info, read network basics)

HTTP: Hypertext transfer protocol is a protocol for the exchange of information between web server and client.

HTTPS: Hypertext transfer protocol is a protocol for the secure exchange of information between web server and client. Most of the websites uses HTTPS to encrypt website user’s data in transit.

IC: Integrated circuit is a single chip in which multiple electronic devices are fabricated.

ICMP: Internet control message protocol is a important network protocol that sends error message,whenever there is a problem in the network.

IGMP: Internet group message protocol is a network protocol for sending message to many people (i.e Group message).

IDS: Intrusion detection system detects unauthorized access to the network or system.

IMAP: Internet message access protocol is a protocol for the retrieval and storage of email. Unlike post office protocol(POP), it supports multiple email access at a time.

IP: Internet protocol is the basic protocol for the transfer of data over a network.

IPS: Intrusion prevention system prevents unauthorized access to the network or system.

IPTV: Internet protocol television network is nothing but the television service over internet.

ISP: Internet service provider provides internet service to the clients. Famous Internet service providers in India are Airtel, vodafone and Reliance.

ISDN: Integrated services digital network is a group of standards for the transmission of audio, video and data over Public switched telephone network(PSTN).

LAN: Local area network is a network of devices in a small area usually of the size of an office or a residential building.

LCD: Liquid crystal display is a output device that displays output based on the optical properties of the liquid crystal.

LED: Light emitting diode is a semiconductor based light source. Main feature of LED is minimal energy consumption.

LIFO: Last in first out is a queue model in which latest requests are served first.

MAC: Media access control is a important network protocol as it addresses devices connected to the network and and it controls the access of physical transmission medium. MAC address: Media access control Address is a 48 bit unique address assigned to the hosts and routers in the network under MAC protocol.

Computing abbreviations Part 1

ADC: Analog to digital converter is a physical device that converts analog signal to digital signal.

ADSL: Asymmetric digital subscriber Line is a data communication technology in which download speed is not equal to the upload speed.

AES: Advanced encryption standard is a standard of encrypting data and it is more secure than than than data encryption standard (DES).

ARP: Address resolution protocol maps the IP address with the physical address of the device i.e MAC address of the device.

AI: Artificial Intelligence is the study of intelligence exhibited by the machines. This technology will replace the human from decision making process.

ALU: Arithmetic Logic unit is the vital unit of CPU and it performs arithmetical and logical operations.

ANN: Artificial Neural networks are sophisticated learning algorithms which are inspired from the biological neural system. They are used in pattern recognition, computer vision and facial recognition.

API: Application programming Interface enables user to create software applications. It acts as an interface between user and computer for software programming.

ARPANET: Advanced research project agency network was developed by US military to facilitate message sharing between its research center. It acts as a precursor of today’s internet.

BASIC: Beginner’s All-purpose Symbolic Instruction Code are class of programming languages which are relatively easy to use.

BIOS: Basic input and output system is a firmware that is programmed into computer’s ROM so that it tests computers hardware every time the system is booted.

CAD: Computer aided design is the use of computer for a design process.

CAM: Computer aided manufacturing is the use of computer for the manufacturing of any goods.

CCTV:Closed circuit television is a method of surveillance by the use of video camera.

CD: Compact disk is a optical disk that uses optical technology to store data in it. Maximum size of data that can be stored in CD is 700 MB (For more info, visit components of computer)

CG: Computer graphics is the process of creating and editing pictures, using computers.

CISC: Complex Instruction Set Computer is used to refer computers that executes many operation with single or few instructions.

DAC: Digital analog converter is a device that converts digital signal into analog signal.

DBMS: Database management system is the software that is used to manage the database. Commonly used DBMS are Oracle, Microsoft SQL server, SAP and MySQL.

DIP: Digital image processing is the use of computing algorithms to process a image.

DES: Data encryption standard is a standard of encrypting data developed in late 1970’s and this standard is now considered as insecure.

DOS: Disk operating system was a operating system that were used before the advent of Graphical user interface based operating system.

Dos: Denial of service is a computer network attack that is intended to deny network’s access to its users.

DDoS: Distributed denial of service is a DOS attack done by more than one computer at a time.

DNS: Domain name system is used for naming any devices or resources which are connected to the network.

DPI: Dots per inch is a measure of printing or scanning quality.

DSL: Digital subscriber line is a data communication technology in which data are transmitted over telephone line.

DSP: Digital signal processing is the manipulation of the digital signal by the means of software or hardware.

DTP: Desktop publishing is the process of creating documents in a personal computer.

DVD: Digital versatile disc is the optical disk and its maximum storage space is 4.7 GB.

DVR: Digital video recorder is device or software that helps in storing video.

Basic computing terms part 3

Recycle bin: Files that are deleted from the hard disk will be moved to Recycle bin. Hence, Recycle bin stores deleted files and they can be restored, when they are needed.

Router: It is a physical device or software that forwards the data in the form of packets to other network.

Registry: It contains vital information about system’s settings, software and hardware configuration. Whenever a software is installed, software’s configuration settings is stored in the registry.

Rootkit: It is a stealth malware designed to enable complete access to the system without being detected.

Scanner: It is a input device that scans photos and papers.

Search engine: It is a software that is designed to search the web by indexing millions of websites. Famous search engine includes AOL,Google, Alta vista, Yahoo search and Bing.

Script: Script is nothing but an program that is usually created to do something automatically.

Skimming: Skimming is the theft of credit or debit card information. Skimmer is the device that is usually inserted into ATM  or POS machine to collect debit card  or credit card information that is stored in the magnetic strip.

Snipper: It is a network spying software or device. It collects all the available information about the network and it tracks all the data sent and received by the network.

Spam: It is unwanted message that is intended to cause annoyance or to do financial fraud.

Spyware: It is a malicious software installed without the knowledge of the user to monitor and store his activity. To know more information, visit Computer threats)

Syntax: Syntax is the general rules which have to be followed while writing a program. Each programming language has different syntax. Syntax is analogous to grammar. If one does not follow syntax while writing program, syntax error will appear.

Telnet: Telnet is the networking protocol that facilitates bidirectional text communication over internet or LAN.

Teleconference:Word “Tele” means “at distance”. Hence teleconference means attending a meeting or conference from any place.

Throughput: Throughput is defined as the amount of data transmitted over a network in a specific time.

Username: It is a unique name that is used to identify a physical person in the network or website. Each username has a password to prevent impersonation.

Virtual reality: It is the technology in which some real life situations or environment are simulated using advanced devices.

Virus: It is a self replicating malicious program.

Virtual memory: It is a technique in which temporary memory usage is transferred from RAM to secondary memory such as hard disk, pen drive, etc. note: High end Games are executed in the computer ,as the computer uses virtual memory. Following image shows the Navy personnel being trained in Virtual reality environment.


Web or World wide web: It is the collection of websites that can be accessed over internet.

Web site: It is the collection of related web pages that are usually hosted in separate domain.

Web browser: It is a software to access web sites and to transfer data over internet.

Web crawlers or spiders or ants: It is a automated program used by search engines for indexing by collecting information about the websites regularly.

Web scraping: It is  the automated process of extracting huge information from websites.

Open source books for TNPSC Group 1 and Civil service(Download)


In this article, you will find some interesting books which will be useful for your exam preparation. I hope that you have downloaded the NCERT books already. If not, i would suggest you to download them in this link.

Download NIOS BOOKS:

NIOS books are useful to form strong foundation in each subject. If you found any broken link, please report.


2. Computing

3. Polity

4.Political science

5. Sociology

6. Indian culture

7. Science and Technology

8. Environmental studies

Note: All the links given above are links to download file in ZIP format. If any of the file ask you a for a password, enter examhacker as password.

I didn’t own copyrights for anyone of the following book.They are owned by OPENSTAX. I am just redistributing them under CC-3.0. Following books are reference book, hence refer through them to maximize your score in preliminary and main exam. Following books are in PDF format.

1.Physics reference book 

2. Principles of Economics

3. Concepts of Biology

4. Sociology Reference book

Updated books

5. Biology Reference book

6. Microeconomics book (Useful for economics optional paper)

7.Macroeconomics book(Useful for economics optional paper)

Above books are given to public domain by OPENSTAX college. You can donate for them in this link. More open books will be added soon.

Basic computing terms part 2

Read previous part of this article in following link(Basic computing terms part 1) before reading this article.

Handshake: It is the process of transmitting information between two devices in order to make connection between two devices. Information transmitted before connection are request to make connection and Acknowledgement to make connection.

Host: It is the device connected to the network while server controls and monitors the network.

Identity theft: It is the illegal way of stealing someone else identity by the use of Information and technology. When you hack your friend’s Facebook password, it is called  identity theft.

Internet: It is the network of networks. It is the biggest network in the world. It uses HTTP and IP protocol. (For more information, please refer Internet and network basics).

Intranet: It is the network of computers in a particular organisation. Intranet is established in order to facilitate transmission of information within the organisation.

Mail: It is the electronic message which can be sent to any computer that is connected to the internet instantly.

Microprocessor: It is the combination of millions of integrated chips. It is integral part of the computer as it processes the data. With the advent of VLSI technology, semiconductor devices are becoming more and more smaller in size.

Modem: It is an acronym of Modulator and demodulator. As the name implies, it modulates the outgoing data and demodulates the incoming data.  Modulation is the process of converting digital signal into analog signal and demodulation does the reverse process.(For more information on digital and audio signal, please refer Internet and network basics).

Multimedia: It is a representation of a digital information in a attractive way such as video, audio, image , graphics ,animation, etc.

Neural networks or Artificial Neural Network(ANN):Neural networks are sophisticated learning algorithms which are inspired from the biological neural system. They are used in pattern recognition, computer vision and facial recognition. ANN uses parallel processing.  ANN will be extremely useful in realizing artificial intelligence.

Open source software: It is freely available software and usually its source code is also available to all people. Sometimes , creator may allow anyone to edit source code redistribute it for any reason.

Operating system: It is the vital program that coordinates system’s hardware and software. It controls all other programs installed in the system(For more info, refer Basics of computing)

Parallel processing: It is the simultaneous use of more the one processors to solve a complex problem. Processes such as data mining, big data analysis, remote sensing needs lot of processors and hence parallel processing is used for above applications. Following picture shows a picture of a super computer named Blue genie which uses parallel processing.


Image credits: Argonne National Lab License: CC-2.0

Pixel: It is the smallest unit of the picture. Quality of the picture is represented by its resolution. Resolution is nothing but the matrix of pixels.

Program: It is the set of instructions that is intended to do a specif task on its execution.

Peer to peer network(P2P): It is a network in which all hosts have equal preference and permission and they usually share the same work. Following image illustrates P2P network. Image credits:


Protocol or Standards: It is the set of rules to be followed by a device while doing specific task.

Basic computing terms part 1

Algorithm: Algorithm is predefined set of instructions that has to be followed in order to solve a computer problem.

Authentication: It is the process of verifying the person’s identity.

Bandwidth: It is the measure of system’s capacity of carrying information over a specified time. Example Bandwidth of RJ-45 cable( RJ-45 is used in LAN) is 100Mbps.

BAR CODE:Barcode is series of parallel lines. Specific information can  be stored in a bacode by varying the distance between two lines, height  and width of the line and this information is decoded by barcode reader.

Binary number: Computer can understand only binary numbers and they are 0 and 1.

Biometric technology: It is the use of biological characteristics of human such as finger print, retina, iris and voice for the purpose of authentication.

Blue ray disc: This optical disc can store high definition movies. Their storage capacity varies from 25 GB to 128 GB while traditional CD’s storage capacity is 4.7 GB.

Cache: Frequently used data are stored in cache in order to enable a faster access by reducing the access time.

Clock rate:  It is the measure of speed of computer’s CPU.  1 hertz represents 1 cycle of input or output.  Modern computer’s clock rate is in the order of Megahertz and Gigahertz.

Computer simulation: The use of computers to simulate a real life event or process is called computer simulation. Computer simulators are used to train people in the field of aviation, defense and so on.

Cookies: Cookies are data stored in the web browser by a website while accessing the data. Some of the cookies are tracked by the advertisers to display preferential advertisement and some other are used by websites for session maintenance.

Cyber crime: It is the use of information and technology to commit crime. Cyber crimes that are liable to punishment under Indian law are hacking, identity theft, Impersonation ,etc

Data mining: It is the process of analyzing enormous amount of data to identify a particular pattern. Data mining is used extensively for targeted advertisement.

Debugging: It is the process of finding and rectifying errors or bugs in the program.

Digital signature: It is used to verify authenticity and integrity of a file and digital message. Digital signature ensures that a particular message or file is created by particular user and it is not edited in the transit.

Download: It is the transfer of file from the web server or from another computer in the network to the user computer.

Ethernet: It is the basic network technology that is used in the LAN and MAN networks.

Firewall: It is the network security system that regulates incoming and outgoing communication of the device or network. They include physical and non physical method to prevent unauthorized access to the device or network.An illustration of firewall is given below. (Image credits: Bruno Pedroza. Copyrights: CC-3.0


Firmware: Basic programs that control the electronic devices are called firmware.

Fuzzy logic: It is the next generation logic system that is aimed to enhance the logic used in the traditional computers. Computers logic understands only two state: True and False. False state is represented by 0 and true is represented by 1 while the fuzzy logic will define all the values that ranges from 0 to 1.