Important Notes of Computer

MPPSC 2019-2020 COMPUTER

What is Computer ?
Ans-  A Computer is an electronic device which can accept data in the prescribed form. ie. in a Specific sequence.

DATA ---- PROCESS---- INFORMATION

Five Generations of Computer -
1. 1940-52----- Electronic valve vacuum tube---- UNIVAC, EDSAC
2. 1952-64----- Transistor --------------------------- IBM-700, ATLAS
3. 1964-71----- Integrated Circuit ----------------- IBM-360
4. 1971--------- Largely Integrated Circuit------- APPLE, DCM
5. Present ----- Optical fibre, Artificial fibre---- ----------------


Fastest Supercomputer - 
SUMMIT --------- 2018 ------ USA

SuperComputer in India -
SuperComputer PARAM 8000 (Made by C-DAC) was launched on july 1 -1991 is Considered India's First Supercomputer.

( C-DAC - Centre for Development of Advanced Computing )

2. Virgo -IIT Madras
3. EKA - Computer Research Laboratories.
4. SAGA-220- ISRO
5. Param Yuva 2 - C-DAC
6. Prithvi - India Institute of Tropical Meteorology , PUNE.


Types of Computer- 


1. Micro Computer - These Computer are used by individual , thus also called PC.

2. Mini Computer -This is 5 to 50 times more powerful than that of a micro Computer.

3. Mainframe Computer-  These are large sized computers . by time sharing and multitasking techniques many people rather than 100 people can work at a time on different terminals of this computer.

4. SuperComputer - These are very powerful computers and have more storage capacity. they are able to process most complex jobs with a very high speed.

5. Quantum Computers - Probably Quantum Computers will be more advanced than that of Human brain. In Quantum Computers Q-Bit will be used in Lieu of Binary Bits.

CPU- Central Processing Unit

CU- Central Unit.

ALU- Arithmetic Logical Unit.

Types Of Memory-

1. Cache Memory
2. Primary Memory
3. Secondary Memory

Cache Memory

The word Cache is pronounced as Cash.
The Cache memory is placed between the CPU and Main Memory ie. It acts as a buffer between the CPU and the Main Memory.

Note -  Primary Memory is only type of memory which is directly accessed by the CPU.

RAM ( Random Access Memory )

RAM is a Volatile Memory with in the computers that is typically used to store data temporarily , so that it can be accessed by the processor.

ROM ( Read Only Memory )

Non Volatile Memory ie. the information stored in it is not lost even if the power supply cut off. It is used for Permanent Storage of Information.

Floppy Disk - A  floppy is made of plastic with magnetic coating on it.

Note - A language acceptable to a computer system is called Programming Language or Computer language.

WWW ( World Wide Web ) -The www is a collection of linked documents or pages , stored on  millions of computers and distributed a across the world.

Web Page -The Hypertext documents in the internet are known as web pages.
A web page is written in a special language  called HTML.

HTML - Hypertext markup language.

URL -( Uniform Resources Locator ) -

Each Web Page has unique address called a URL ( Or Web Address) which identifies its location on the internet.

The format of URL Contains four parts -  protocol name of the web server ( or domain name ), path and file name.
ex- http://www
      http is a protocol
      host name  - www.gkgsboss.blogspot.com
      file name  -  index.html

Domain type- 

com  - Commercial
gov   - Governmental
net    - network resource
org    - Non profit Organisation.
mil    - military
edu    - colleges and universities 
info    - informational organisation

Domain Name for Countries-
uk- united kingdom
in - india
us- united states 
de - germany
etc....


Web Browser -

It is a special software that enables users to read.
ex -
1. Internet Explorer
2. Mozilla Firefox
3. NetScape Navigator
4. Google Chrome
5. Apple Safari
6. Microsoft Edge.
7. Vivaldi
8. Camino
9. Surf
10. Palemoon
11. Sea Monkey
12. Maxthon
13. Epiphany
14. Phoenix
15. Cyberdog
16. Amaya
17. Voyager
18. Mosaic
19. Cello
20. Agora
21. Grail.
22. Chromimum
23. Avant Browser
24. Kon Queror
25. Lynx
26. Torch
27. Rockmelt
28. K- Meleon
29. Midori
30. Luna Scape
31. Icab
32. Epic
33. Comodo ice dragon
34. Dillo
35. Arora
36. Galeon
37. Aol Explorer

Difference Between Malware, Trojan, Virus, and Worm

Malware 

Any software intentionally designed to cause damage to a computer, server or computer network. Malware does the damage after it is implanted or introduced in some way into a target’s computer and can take the form of executable code, scripts, active content, and other software.

Malware can be classified based on how they get executed, how they spread, and/or what they do. Some of them are –

Viruses

Worms

Trojan horses

Spyware

Hoax

Computer Viruses – 

It is a type of malicious software program ( Malware) that, when executed , replicates itself by modifying other computer programs and inserting its own code.

VIRUS- Vital Information Resources under Siege.

List of most destructive computer virus

Worms

Worms disseminates from computer to computer, but unlike a virus, it has the capability to travel without any human action. worms are malicious programs that copy themselves from system to system, rather than infiltrating legitimate files. The example would be for a worm to send a copy of itself to everyone listed in your e-mail address book. 

the worm replicates and sends itself 

Trojan horse

A type of malicious software program , Trojans do not replicate or reproduce through infection. Trojans may allow an attacker to access users' personal information such as banking information, passwords, or personal identity. It can infect other devices connected to the network. Ransomware attacks are often carried out using a Trojan.

Spyware

Malware that collects information about the usage of the infected computer and communicates it back to the attacker. "Spyware" is mostly classified into four types: adware, system monitors, tracking cookies, and trojans, Spyware can collect almost any type of data, including personal information like internet surfing habits, user logins, and bank or credit account information. 

Spyware can also interfere with a user's control of a computer by installing additional software or redirecting web browsers. Some spyware can change computer settings, which can result in slow Internet connection speeds, unauthorized changes in browser settings, or changes to software settings.

MPPSC 2019 COMPUTER

World Wide Web

The World Wide Web, also known as the WWW and the Web, is an information space where documents and other web resources are identified by Uniform Resource Locators (URLs), interlinked by hypertext links, and accessible via the Internet.

 Tim Berners-Lee invented the World Wide Web in 1989. He wrote the first web browser in 1990 while employed at CERN near Geneva, Switzerland.

The terms Internet and World Wide Web are often used without much distinction. However, the two are not the same. The Internet is a global system of interconnected computer networks. In contrast, the World Wide Web is a global collection of documents and other resources, linked by hyperlinks and URIs. Web resources are accessed using HTTP or HTTPS, which are application-level Internet protocols that use the Internet's transport protocols.

Web caching

A web cache is a server computer located either on the public Internet, or within an enterprise that stores recently accessed web pages to improve response time for users when the same content is requested within a certain time after the original request. 

Web server

A Web server is a program that uses HTTP(Hypertext Transfer Protocol) to serve the files that form Web pages to users, in response to their requests, which are forwarded by their computers'HTTP clients. Dedicated computers and appliances may be referred to as Web servers as well.

Spam

Spam refers to the use of electronic messaging systems to send out unrequested or unwanted messages in bulk.

The most common form of spam is email spam, but the term also applies to any message sent electronically that is unsolicited and bulk. This includes: instant message spam, search engine spam, blog spam, Usenet newsgroup spam, wiki spam, classified ads spam, Internet forum spam, social media spam, junk fax spam, and so on.

Videoconferencing

A video conference is a live, visual connection between two or more people residing in separate locations for the purpose of communication. At its simplest, video conferencing provides transmission of static images and text between two locations. At its most sophisticated, it provides transmission of full-motion video images and high-quality audio between multiple locations.

Or

Video conferencing refers to conducting a video conference or video teleconference in which two or more sets of hardware and software interact while simultaneously transmitting and receiving video and audio signals from two or more geographic locations. Video conferencing may also involve sharing documents, various presentation materials, whiteboards, flip charts and similar group presentation visual aids.

list of video conferencing software

ClickMeeting 

Livestorm

Flock

Zoho Meeting

Samepage

BigMarker 

A suite

TeamViewer's 

Cisco WebEx

ReadyTalk

Cybercrime

Cybercrime is defined as a crime in which a computer is the object of the crime (hacking, phishing, spamming) or is used as a tool to commit an offense (child pornography, hate crimes). Cybercriminals may use computer technology to access personal information, business trade secrets or use the internet for exploitative or malicious purposes. Criminals can also use computers for communication and document or data storage. Criminals who perform these illegal activities are often referred to as hackers.

Phishing 

Phishing is the fraudulent attempt to obtain sensitive information such as usernames, passwords and credit card details by disguising as a trustworthy entity in an electronic communication.

Or

Phishing is a type of social engineering attack often used to steal user data, including login credentials and credit card numbers. It occurs when an attacker, masquerading as a trusted entity, dupes a victim into opening an email, instant message, or text message.

Cyberstalking

Cyberstalking is a criminal practice where an individual uses the Internet to systematically harass or threaten someone. This crime can be perpetrated through email, social media, chat rooms, instant messaging clients and any other online medium. Cyberstalking can also occur in conjunction with the more traditional form of stalking, where the offender harasses the victim offline. There is no unified legal approach to cyberstalking, but many governments have moved toward making these practices punishable by law. 

Cyberstalking is sometimes referred to as Internet stalking, e-stalking or online stalking.

denial of service

A Denial-of-Service (DoS) attack is an attack meant to shut down a machine or network, making it inaccessible to its intended users. DoS attacks accomplish this by flooding the target with traffic, or sending it information that triggers a crash. In both instances, the DoS attack deprives legitimate users (i.e. employees, members, or account holders) of the service or resource they expected.

hacker

A hacker is an individual who uses computer, networking or other skills to overcome a technical problem. The term hacker may refer to anyone with technical skills, but it often refers to a person who uses his or her abilities to gain unauthorized access to systems or networks in order to commit crimes. A hacker may, for example, steal information to hurt people via identity theft, damage or bring down systems and, often, hold those systems hostage to collect ransom.

However, the term is more commonly applied to an individual who uses this skill for illegal or unethical purposes.

Types of hackers

white hat hacker

A white hat hacker is a computer security specialist who breaks into protected systems and networks to test and asses their security. White hat hackers use their skills to improve security by exposing vulnerabilities before malicious hackers (known as black hat hackers) can detect and exploit them. Although the methods used are similar, if not identical, to those employed by malicious hackers, white hat hackers have permission to employ them against the organization that has hired them.

White hat hackers are usually seen as hackers who use their skills to benefit society. They may be reformed black hat hackers or they may simply be well-versed in the methods and techniques used by hackers. 

Or

An ethical hacker (also known as a white hat hacker) is the ultimate security professional. Ethical hackers know how to find and exploit vulnerabilities and weaknesses in various systems—just like a malicious hacker (or a black hat hacker). In fact, they both use the same skills; however, an ethical hacker uses those skills in a legitimate, lawful manner to try to find vulnerabilities and fix them before the bad guys can get there and try to break in.

Black hat hackers

Black hat hackers intentionally gain unauthorized access to networks and systems with malicious intent, whether to steal data, spread malware or profit from ransomware, vandalize or otherwise damage systems or for any other reason -- including gaining notoriety. Black hat hackers are criminals by definition because they violate laws against accessing systems without authorization, but they may also engage in other illegal activity, including identity theft and distributed denial-of-service attacks.

Gray hat hackers

Gray hat hackers fall somewhere between white hat hackers and black hat hackers. While their motives may be similar to those of white hat hackers, gray hats are more likely than white hat hackers to access systems without authorization; at the same time, they are more likely than black hat hackers to avoid doing unnecessary damage to the systems they hack. Although they aren't typically -- or only -- motivated by money, gray hat hackers may offer to fix vulnerabilities they have discovered through their own, unauthorized, activities rather than using their knowledge to exploit vulnerabilities for illegal profit.

Cracker

A cracker is someone who breaks into someone else's computer system, often on a network; bypasses passwords or licenses in computer programs; or in other ways intentionally breaches computer security. A cracker can be doing this for profit, maliciously, for some altruistic purpose or cause, or because the challenge is there. Some breaking-and-entering has been done ostensibly to point out weaknesses in a site's security system.

The crackers are also known as Black Hats. They gain access to the accounts of people maliciously and they can misuse the secured information across networks.

Hacker vs. cracker

Within the hacker-cracker framework, hackers are those who seek to identify flaws in security systems and work to improve them, including security experts tasked with locating and identifying flaws in systems and fixing those vulnerabilities. Crackers, on the other hand, are intent on breaching computer and network security to exploit those same flaws for their own gain.

Script kiddie

n programming and hacking culture, a script kiddie, skiddie,^[1] or skid is an unskilled individual who uses scripts or programs developed by others to attack computer systems and networks and deface websites. It is generally assumed that most script kiddies are juveniles who lack the ability to write sophisticated programs or exploits on their own and that their objective is to try to impress their friends or gain credit in computer-enthusiast communities.

video chatting & videoconferencing

While video chatting is often used interchangeably with the term videoconferencing -- and there is considerable overlap between the two -- in most cases videoconferencing refers to multipoint (3 or more participants) audio and video interaction deployed in a business setting, whereas video chatting most frequently refers to one-to-one video calls made via software apps like Skype.

Video conference refers to a communication over a distance between three or more people where video and audio is transmitted in near real-time.

Conduct of video call using telecom technology.

Ethernet

Ethernet is the traditional technology for connecting wired local area networks (LANs), enabling devices to communicate with each other via a protocol -- a set of rules or common network language.

LAN, a MAN, and a WAN

LAN

A LAN (local area network) is a group of computers and network devices connected together, usually within the same building. By definition, the connections must be high speed and relatively inexpensive (e.g., token ring orEthernet). Most Indiana University Bloomington departments are on LANs.

A LAN connection is a high-speed connection to a LAN. On the IUB campus, most connections are either Ethernet (10 Mbps) or Fast Ethernet (100 Mbps), and a few locations have Gigabit Ethernet (1000 Mbps) connections.

MAN 

A MAN (metropolitan area network) is a larger network that usually spans several buildings in the same city or town. The IUB network is an example of a MAN.

WAN 

A WAN (wide area network), in comparison to a MAN, is not restricted to a geographical location, although it might be confined within the bounds of a state or country. A WAN connects several LANs, and may be limited to an enterprise (a corporation or an organization) or accessible to the public. The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN.

Modem

A modem modulates outgoing digital signals from a computer or other digital device to analog signals for a conventional copper twisted pair telephone line and demodulates the incoming analog signal and converts it to a digital signal for the digital device.

DSL (Digital Subscriber Line)

DSL (Digital Subscriber Line) is a technology for bringing high- bandwidth information to homes and small businesses over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL, HDSL, and RADSL.

Memory Units 

a) Bit - It is a starting Memory unit It is a value of smallest digital measurement. it has two possible values off or 0 and on or  1.

b) Nibble -  it is equal to 4 bits.

c) Byte - it has 8 bits.

d) Kilobyte - A kilobyte is 1024 bytes.

e) Megabyte - it has 1024 kilobytes.

f) Gigabyte - it is equal to 1024 megabytes or 1048576 bytes.

g) Terabyte - it is equal to 1024 gigabytes or 1048576 megabytes.

h) Petabyte -  it is equal to 1024 terabytes or 1048576  gigabytes.

i) Exabyte - it is equal to 1024 petabytes or 1048576 terabytes.

j) Zettabyte -it is equal to 1024 exabytes or 1048576 petabytes.

k) Yottabyte - it is equal to 1024 zettabytes or 1048576  exabytes.

Binary 

Binary is a base 2 number system invented by Gottfried Leibniz that is made up of only two numbers: 0 and 1.

This number system is the basis for all binary code, which is used to write data such as the instructions that computer processors use, or the digital text you read every day.

Fireball (software)

Fireball is a form of malware orchestrated by Rafotech, a Beijing-based digital marketing agency, that has infected up to 250 million Windows and MacOS computers, according to Check Point software.

Once it infects a computer, Fireball takes over the PC's browsers and turns them into zombies, enabling the Fireball Browser Hijack malware to run any code on the infected computer as well as hijacking and manipulating the web traffic of the infected PC to help generate fraudulent ad revenue.

Country	% infected	Number of infections (in millions)	Hit Rate
India	10.1%	25.3	43%
Brazil	9.6%	24.1	38%
Mexico	6.4%	16.1	N/A
Indonesia	5.2%	13.1	60%
US	2.2%	5.5	10.7%

ALL COMPUTER RELATED FULL FORM

Internet Related

HTTP - Hypertext Transfer Protocol

HTML - Hypertext Markup Language

HTTPS - Hypertext Transfer Protocol Over Secure Sockets Layer

PHP - Hypertext Preprocessor

SASS - Syntactically Awesome Style Sheets

PERL - Practical Extraction and Reporting Language

UI - User Interface

ASP - Active Server Pages

NET - Internet

WP - WordPress

WWW - World Wide Web

API - Application Programming Interfaces

BIOS - Basic Input/Output System

DNS - Domain Name Service Or Domain Name Server

DPI - Dots Per Inch

DVI - Digital Visual Interface

FAT - File Allocation Table

FPS - Frame Per Second

EMI - Electromagnetic Interference

GBps - Gigabytes per second or Gigabits per second

GHz - Gigahertz

GUI - Graphical User Interface

Mbps - Mega Bytes Per second

MHz - Megahertz

MP3 - Moving Picture Experts Group Layer 3 Audio

MPEG - Moving Picture Experts Group

NTFS - New Technology File System

OMR -  Optical Mark Recognition

SD - SECURE DIGITAL

PC - Personal Computer

OS - Operating System

VDU - Visible Display Unit

ZIP - Zigzag Inline Package

IT - Information Technology

ISO - International Standards Organization

AMD - Advanced Micro Devices
CD - Compact Disc
CD-ROM - Compact Disc-Read-Only Memory
CD-RW - Compact Disc-Rewritable
Computer - Commonly Operated Machine Particularly Used In Technical And Educational Research.
CPU - Central Processing Unit
DVD - Digital Versatile Disc
DVD-ROM - Digital Video Disc-Random Access Memory
DDR - Double Data-Rate
FDD - Floppy Disk Drive
HDD - Hard Disk Drive
HDMi -High Definition Media Interface
LCD - Liquid Crystal Display
LED- Light Emitting Diode
USB - Universal Serial Bus
VGA - Video Graphics Array
VRAM - Video Random Access Memory


.sub -Subtitle File
.wav - Waveform PCM Audio
.mp3 - MPEG Audio Layer 3
.mp4 - MPEG Layer 4
.avi - Audio Video Interleave
.flv - Flash Video
.wmv - Windows Media Video
.mpeg   - Moving Picture Experts Group
.ppt - PowerPoint Presentation
.pdf - Portable Document Format
.gif - Graphics Interchange Format
.docx - Document (without Macros)
.docm - Document (with Macros)


IMDb - The Internet Movie Database
DELL - Digitle Electronic Link Library
WIPRO- Western Indian Products
HP - Hewlett-Packard
LG - Life’s Good
INTEL - Integrated Electronics
YAHOO - Yet Another Hierarchical Officious Oracle
IBM - International Business Machines Corporation