OSI ISO MODEL

It is a model.

It is not a protocol.

ISO(International Standards Organisation)
OSI(Open System Interconnect)

OSI is a model developed by ISO which describes how data from application on one computer can be transferred to an application on another computer.

I know u need to know short-cut....right?????

All   People  Seem  To  Need  Data  Processing.

(Application,Presentation,Session,Transport,Network,DataLink,
Physical Layers.)

The Seven Layers of the OSI Model
Layer	Name	Description
1	Physical	Governs the layout of cables and devices such as repeaters and hubs.
2	Data Link	Provides MAC addresses to uniquely identify network nodes and a means for data to be sent over the Physical layer in the form of packets. Bridges and switches are layer 2 devices.
3	Network	Handles routing of data across network segments.
4	Transport	Provides for reliable delivery of packets.
5	Session	Establishes sessions between network applications.
6	Presentation	Converts data so that systems that use different data formats can exchange information.
7	Application	Allows applications to request network services.

Layer	Description	Examples
7. Application	Responsible for initiating or services the request.	SMTP, DNS, HTTP, and Telnet
6. Presentation	Formats the information so that it is understood by the receiving system.	Compression and encryption depending on the implementation
5. Session	Responsible for establishing, managing, and terminating the session.	NetBIOS
4. Transport	Breaks information into segments and is responsible for connection and connectionless communication.	TCP and UDP
3. Network	Responsible for logical addressing and routing	IP, ICMP, ARP, RIP, IGRP, and routers
2. Data Link	Responsible for physical addressing, error correction, and preparing the information for the media	MAC address, CSMA/CD, switches, and bridges
1. Physical	Deals with the electrical signal.	Cables, connectors, hubs, and repeaters

How to set One or more Home pages in Firefox OR other web-browsers

Home Page :  U separate your wishing links between OR "|"

Security services

1) Confidentiality:

To keep a message secret to those that are not authorized to read it.

2) Authentication:

To verify the identity of the user/computer.

3) Access Control:

To be able to tell who can do what with which resource.

4) Integrity: 

To make sure that a message has not been changed while on transfer.

5) Non-repudiation:

To make sure that a user can not deny later having participated in a transaction.

6) Availability:

To make sure that the services are always available to users.

How can I download my information from Facebook?

1. Choose Account Settings
2. Click on "Download a copy of your Facebook data"
3. Click Start My Archive

Keep it safe : 

What's in your archive?

• Photos or videos you've shared on Facebook
• Your Wall posts, messages and chat conversations
• Your friends' names and some of their email addresses

(Note: We'll only include email addresses for friends who've allowed this in their account settings.)

What's not in your archive?

• Your friends' photos and status updates
• Other people's personal info
• Comments you've made on other people's posts

How do I permanently delete my account?

https://www.facebook.com/help/delete_account

WHAT IS VIRUS,ADWARE,SPYWARE,WORMS,TROJAN HORSE,PHISHING,ROOTKIT

Computer Virus: A computer virus is a program that can replicate  itself inside one computer and also spread from computer to computer. Computer viruses work by attaching themselves to existing legitimate programs.

Adware: Advertising-supported software or adware is any software package that automatically plays, displays or downloads advertisements to a computer. You may see these routinely as “pop-ups” or windows that pop-up when you go to a website. You can turn these off in your browser, but you may or may not determine that blocking pop-ups is more trouble than it is worth.

Spyware: Designed to gather personal, private information from your computer. If the program is designed to capture login and passwords, it is sometimes called a keylogger.
                               Keylogger: A program that is designed to log keystrokes on a computer in a manner that the user is unaware of the data capture, record them and transmit the information to another computer for use in a variety of ways. Some companies use this method to monitor their employees’ computer activities, but it can be used for illegal and malicious reasons.

Worms: A computer worm can use a computer network to send copies of itself to other computers (nodes) on the network. Worms are always harmful even if they do nothing but copy themselves because they can ultimately use up all of the computer’s memory.

Trojan Horse: Designed to steal information or harm the computer system. The term comes from the Greek story of the Trojan War. Adware is a form of Trojan Horse program. The Trojan Horse often gets into your computer when you click on an unsolicited ad or email to download a “free” copy of a program.

Phishing: An unsolicited, fake message or email that appears to be legitimate asking you to send personal, private information such as credit card numbers, phone numbers, birth information (birth place, birth date), or any other type of information. These messages may have a genuine-looking logo or look like official letters. Again, never, never, never respond to an unsolicited message from anyone with any kind of information. Just clicking on the link may give the remote computer your personal information or, at least, tell the sender that they have a valid email address or that you are too naive to avoid their scam. 

Rootkit: A program installed on your computer to allow someone remote access to your computer without your knowledge or permission. This can be as simple as a relative or member of your family that uses your computer without your permission by stealing your password and then using it to set up an account or user on your computer. 

Trojan Horse Virus History.....

Trojan Horse in TROY Film

The Trojan Horse is a crafty contraption that allowed the Greeks to put an

end to the 10-year-old Trojan War. The wily Greek hero Odysseus conceived

the project and design for the Trojan Horse ; Epeus, is credited with the

actual building of the Trojan Horse.

The Greeks left a giant wooden object made to look like a horse at the Trojan 

city gates. Some of the Greeks pretended to sail away, but actually sailed 

just out of sight. The other Greeks stood waiting, inside the belly of the 

wooden beast.

When the Trojans saw the giant wooden horse and the departing Greek 

troops, they thought the wooden horse was a parting gift for the gods, so 

most of them wanted to wheel it into their city. The decision to move the 

Trojan Horse into the city was opposed by Cassandra, the prophetess whose 

fate was never to be believed, and Laocoon, who was destroyed, along with 

his two sons, by sea serpents after pleading with his fellow Trojans to leave 

the Trojan Horse outside their city walls. The Trojans took this as a sign that 

the gods were displeased with Laocoon's message. Besides, the Trojans 

preferred to believe that since the Greeks were gone, the long war was over. 

The city opened the gates, let the horse in, and celebrated riotously. When 

the Trojans passed out or fell asleep, the Greeks climbed down from the belly 

of the Trojan Horse, opened the city gates and ushered the rest of the troops 

into the city. The Greeks then sacked, destroyed, and burned Troy.

Trojan Horse Virus

  Trojan horse sitting invisibly in an infected computer and this program gives full control of that computer. 

   Trojans do not attempt to inject themselves into other files like a computer virus. 

   Trojan horses may steal information, or harm their host computer systems.

   Trojan horses in this way may require interaction with a hacker to fulfill their purpose, though the hacker does not have to be the individual responsible for distributing the Trojan horse. 

   It is possible for individual hackers to scan computers on a network using a port scanner in the hope of finding one with a malicious Trojan horse installed, which the hacker can then use to control the target computer.

U know about "Turing_test"????

Turing-Test

why apple logo is bitten ???

For years it has been rumored that Apple's iconic logo, a stylized, solid white apple missing 

a bite on one side, was inspired by circumstances surrounding the death of Alan Turing, the 

groundbreaking mathematician and computer scientist who committed suicide  by eating a 

cyanide-laced apple in 1954.

Unraveling the tale behind the Apple logo

Protect Your Folder From Anyone including admin !!!!!!!!

Click-here

Searching Datastrures,Computer Networks,Computer Organisation PPTs

My Answer

1

Searching Ebooks???

Enjoy

Working of a Virus

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Answer

Difference between Virus and Worm???

A virus is a program that is designed to spread from file to file on a single PC, it does not intentionally try to move to another PC, and it must replicate, and execute itself to be defined as a virus.

A worm is designed to copy itself (intentionally move) from PC to PC, via networks, internet etc. A worm doesnt need a host file to move from system to system, whereas a virus does. So worms spread more rapidly then viruses.

                   The difference between a worm and a virus is that a virus does not have a propagation vector.i.e. it will only effect one host and does not propagate to other hosts. Worms propagate and infect other computers. Majority of threats are actually worms that propagate to other hosts.

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What is Information Security?? Cryptography means??

Simply....we can say

"Securing information from unauthorized users".

Cryptography: Secret writing.