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Student Notes for Computer Science And Computer Applications
Student Notes for Computer Science And Computer Applications
Student Notes for Computer Science And Computer Applications
Internet Communications Protocols TCP/IP TCP and IP were developed by a department of defense (DOD) research project to connect a number different networks designed by different vendors into a networks of networks. It was initially successful because it delivered a few basic services that everyone needs file transfer, electronic mail, remote logon across a very large number of client and server systems. Several computers in a small department can use TCP/IP on a single LAN. IP: IP is responsible for moving packet of data from node to node. IP forwards each packet based on a four byte destinations address. The internet authorities assign ranges of numbers to different organizations. The organizations assign groups of their numbers to departments. IP operates on gate way machines that move data from department to organizations to region and then around the world. TCP: TCP is responsible for verifying the correct delivery of data from client to server. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received. INTERNET HOST : Each computer on the internet is called a host computer. The computers on the internet are millions of internet hosts, are connected by cables, phone lines and satellite connections. Internet protocol (IP) address IP defines a universal addressing scheme called IP address. An IP address is a 32 bit binary addressing scheme and each standard address is unique on the internet. IP addressing scheme is used to identify networks, networks devices and network
Internet Communications Protocols TCP/IP TCP and IP were developed by a department of defense (DOD) research project to connect a number different networks designed by different vendors into a networks of networks. It was initially successful because it delivered a few basic services that everyone needs file transfer, electronic mail, remote logon across a very large number of client and server systems. Several computers in a small department can use TCP/IP on a single LAN. IP: IP is responsible for moving packet of data from node to node. IP forwards each packet based on a four byte destinations address. The internet authorities assign ranges of numbers to different organizations. The organizations assign groups of their numbers to departments. IP operates on gate way machines that move data from department to organizations to region and then around the world. TCP: TCP is responsible for verifying the correct delivery of data from client to server. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received. INTERNET HOST : Each computer on the internet is called a host computer. The computers on the internet are millions of internet hosts, are connected by cables, phone lines and satellite connections. Internet protocol (IP) address IP defines a universal addressing scheme called IP address. An IP address is a 32 bit binary addressing scheme and each standard address is unique on the internet. IP addressing scheme is used to identify networks, networks devices and network
Internet Communications Protocols TCP/IP TCP and IP were developed by a department of defense (DOD) research project to connect a number different networks designed by different vendors into a networks of networks. It was initially successful because it delivered a few basic services that everyone needs file transfer, electronic mail, remote logon across a very large number of client and server systems. Several computers in a small department can use TCP/IP on a single LAN. IP: IP is responsible for moving packet of data from node to node. IP forwards each packet based on a four byte destinations address. The internet authorities assign ranges of numbers to different organizations. The organizations assign groups of their numbers to departments. IP operates on gate way machines that move data from department to organizations to region and then around the world. TCP: TCP is responsible for verifying the correct delivery of data from client to server. Data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received. INTERNET HOST : Each computer on the internet is called a host computer. The computers on the internet are millions of internet hosts, are connected by cables, phone lines and satellite connections. Internet protocol (IP) address IP defines a universal addressing scheme called IP address. An IP address is a 32 bit binary addressing scheme and each standard address is unique on the internet. IP addressing scheme is used to identify networks, networks devices and network
Another way to find an IP address
Top-level domain The way to understand an address is to read from right to left. In general there are two types of top level domains. I. Generic domains/organization domains II. Country Domains/Geographical domains
1. Generic domains/Organization domains Organizations domains are based on an addressing scheme developed before the days of international networks .edu Servers that provide educational services .gov About the government of a country .mil Servers that provide military information .org Provide information about the organizations in the world .com Servers providing commercial services on the internet .net Information services / networks .int Organizations established by international treaty ii. Country Domains/Geographical domains The international top level domain uses a 2-letter country code. Country code toplevel domains are two letter destinations assigned to individual countries. Each country linked to the web has a two letter top level domain. The following table shows the various country code top level domains Domain Country Domain country Domain country .in India .co Colombia .mx Mexico .aq Antarctica .dk Denmark .nz New Zealand .at Australia .eg Egypt .om Oman .bd Bangladesh .af Afghanistan .pk Pakistan .bm Bermuda .jp Japan .qa Qatar .br brazil .it Italy .sa Saudi Arabia .ca Canada .is island .th Thailand .cn china .kw Kuwait .us United states .cu Cuba .lk Srilanka .uk United kingdom Top-level domain The way to understand an address is to read from right to left. In general there are two types of top level domains. I. Generic domains/organization domains II. Country Domains/Geographical domains 1. Generic domains/Organization domains Organizations domains are based on an addressing scheme developed before the days of international networks .edu Servers that provide educational services .gov About the government of a country .mil Servers that provide military information .org Provide information about the organizations in the world .com Servers providing commercial services on the internet .net Information services / networks .int Organizations established by international treaty ii. Country Domains/Geographical domains The international top level domain uses a 2-letter country code. Country code toplevel domains are two letter destinations assigned to individual countries. Each country linked to the web has a two letter top level domain. The following table shows the various country code top level domains Domain Country Domain country Domain country .in India .co Colombia .mx Mexico .aq Antarctica .dk Denmark .nz New Zealand .at Australia .eg Egypt .om Oman .bd Bangladesh .af Afghanistan .pk Pakistan .bm Bermuda .jp Japan .qa Qatar .br brazil .it Italy .sa Saudi Arabia .ca Canada .is island .th Thailand .cn china .kw Kuwait .us United states .cu Cuba .lk Srilanka .uk United kingdom Top-level domain The way to understand an address is to read from right to left. In general there are two types of top level domains. I. Generic domains/organization domains II. Country Domains/Geographical domains 1. Generic domains/Organization domains Organizations domains are based on an addressing scheme developed before the days of international networks .edu Servers that provide educational services .gov About the government of a country .mil Servers that provide military information .org Provide information about the organizations in the world .com Servers providing commercial services on the internet .net Information services / networks .int Organizations established by international treaty ii. Country Domains/Geographical domains The international top level domain uses a 2-letter country code. Country code toplevel domains are two letter destinations assigned to individual countries. Each country linked to the web has a two letter top level domain. The following table shows the various country code top level domains Domain Country Domain country Domain country .in India .co Colombia .mx Mexico .aq Antarctica .dk Denmark .nz New Zealand .at Australia .eg Egypt .om Oman .bd Bangladesh .af Afghanistan .pk Pakistan .bm Bermuda .jp Japan .qa Qatar .br brazil .it Italy .sa Saudi Arabia .ca Canada .is island .th Thailand .cn china .kw Kuwait .us United states .cu Cuba .lk Srilanka .uk United kingdom
activity logging. FTP servers are accessed by a FTP client who allows the user to move the files between the server computer and the client computer. NEWS servers: They work as source of distributions and delivery for hundreds of available public news groups accessible over the USENET news network. USENET is global bulletin board system that can be approach via internet or via a variety of online services IRC servers: Internet relay chat is comprised of various independent networks of servers that allow users to connect to each other via an IRC network. It is an option for those who seeking real time competence. PORT AND PORT NUMBERS: A port is an additional 16 bit number that uniquely identifies the particular service on any given machine on the internet. Port numbers are 16 bit wide, therefore each computer on the internet has a maximum number of 216 or 65,536 ports. The particular application is identified by its unique port number in the same way that a specific television station has a unique channel number. Port numbers are divided into three ranges: Well-known ports are those from 0 through 1,023. Registered ports are those from 1,024 through 49,151. Dynamic and private ports are those from 49,152 through 65,535. These ports are controlled and assigned by the internet assigned number authority (IANA). The following table shows the protocol port numbers: Port Number Protocol 21 File Transfer Protocol (FTP) 25 Simple Mail Transfer Protocol (SMTP) 80 Hyper Text Transfer Protocol (HTTP) 110 Post Office Protocol 3 (POP 3) activity logging. FTP servers are accessed by a FTP client who allows the user to move the files between the server computer and the client computer. NEWS servers: They work as source of distributions and delivery for hundreds of available public news groups accessible over the USENET news network. USENET is global bulletin board system that can be approach via internet or via a variety of online services IRC servers: Internet relay chat is comprised of various independent networks of servers that allow users to connect to each other via an IRC network. It is an option for those who seeking real time competence. PORT AND PORT NUMBERS: A port is an additional 16 bit number that uniquely identifies the particular service on any given machine on the internet. Port numbers are 16 bit wide, therefore each computer on the internet has a maximum number of 216 or 65,536 ports. The particular application is identified by its unique port number in the same way that a specific television station has a unique channel number. Port numbers are divided into three ranges: Well-known ports are those from 0 through 1,023. Registered ports are those from 1,024 through 49,151. Dynamic and private ports are those from 49,152 through 65,535. These ports are controlled and assigned by the internet assigned number authority (IANA). The following table shows the protocol port numbers: Port Number Protocol 21 File Transfer Protocol (FTP) 25 Simple Mail Transfer Protocol (SMTP) 80 Hyper Text Transfer Protocol (HTTP) 110 Post Office Protocol 3 (POP 3) activity logging. FTP servers are accessed by a FTP client who allows the user to move the files between the server computer and the client computer. NEWS servers: They work as source of distributions and delivery for hundreds of available public news groups accessible over the USENET news network. USENET is global bulletin board system that can be approach via internet or via a variety of online services IRC servers: Internet relay chat is comprised of various independent networks of servers that allow users to connect to each other via an IRC network. It is an option for those who seeking real time competence. PORT AND PORT NUMBERS: A port is an additional 16 bit number that uniquely identifies the particular service on any given machine on the internet. Port numbers are 16 bit wide, therefore each computer on the internet has a maximum number of 216 or 65,536 ports. The particular application is identified by its unique port number in the same way that a specific television station has a unique channel number. Port numbers are divided into three ranges: Well-known ports are those from 0 through 1,023. Registered ports are those from 1,024 through 49,151. Dynamic and private ports are those from 49,152 through 65,535. These ports are controlled and assigned by the internet assigned number authority (IANA). The following table shows the protocol port numbers: Port Number Protocol 21 File Transfer Protocol (FTP) 25 Simple Mail Transfer Protocol (SMTP) 80 Hyper Text Transfer Protocol (HTTP) 110 Post Office Protocol 3 (POP 3)
The domain address is converted into number internally. The part of the internet that keeps track of address is called the DNS domain name system DNS server is a computer that translates the domain name of another in to an IP address and vice versa on request. Every computer in the network has an IP address, which specifies its physical network connection. To locate the information in internet two kinds of address can be used. These are domain names and IP addresses. Domain names follow a format called Domain name system. EXCHANGING E-MAIL: Email concepts: Email allows the user to send data in the form of text, pictures, sound and video to a remote computer on the internet. These email services are created by companies on specific web services and can be accessed by anyone anywhere in the world at anytime. Some of the familiar servers that offer free email services on the internet are Yahoo, Rediff, Gmail and Hotmail and etc. These three things that you must have to send and receive email An internet email account A connection to the internet A software application that handles email Receiving incoming messages: The incoming messages are received in an email mailbox that resides on a mail server. Depending upon the type of connection that you have, download e-mail from the mail server to your computer or you may read your e-mail from the mail server. Mail server receives and stores email messages in mail boxes by using a protocol called post office protocol 3(POP 3) or internet message access protocol (IMAP) Sending outgoing messages: Write email messages on your computer by using e-mail applications. Then, transfer the messages to an SMTP (simple mail transfer protocol) server, a mail server that accepts outgoing e-mail. The SMTP server that takes care of sending your e-mail messages may be a different server.
The domain address is converted into number internally. The part of the internet that keeps track of address is called the DNS domain name system DNS server is a computer that translates the domain name of another in to an IP address and vice versa on request. Every computer in the network has an IP address, which specifies its physical network connection. To locate the information in internet two kinds of address can be used. These are domain names and IP addresses. Domain names follow a format called Domain name system. EXCHANGING E-MAIL: Email concepts: Email allows the user to send data in the form of text, pictures, sound and video to a remote computer on the internet. These email services are created by companies on specific web services and can be accessed by anyone anywhere in the world at anytime. Some of the familiar servers that offer free email services on the internet are Yahoo, Rediff, Gmail and Hotmail and etc. These three things that you must have to send and receive email An internet email account A connection to the internet A software application that handles email Receiving incoming messages: The incoming messages are received in an email mailbox that resides on a mail server. Depending upon the type of connection that you have, download e-mail from the mail server to your computer or you may read your e-mail from the mail server. Mail server receives and stores email messages in mail boxes by using a protocol called post office protocol 3(POP 3) or internet message access protocol (IMAP) Sending outgoing messages: Write email messages on your computer by using e-mail applications. Then, transfer the messages to an SMTP (simple mail transfer protocol) server, a mail server that accepts outgoing e-mail. The SMTP server that takes care of sending your e-mail messages may be a different server.
The domain address is converted into number internally. The part of the internet that keeps track of address is called the DNS domain name system DNS server is a computer that translates the domain name of another in to an IP address and vice versa on request. Every computer in the network has an IP address, which specifies its physical network connection. To locate the information in internet two kinds of address can be used. These are domain names and IP addresses. Domain names follow a format called Domain name system. EXCHANGING E-MAIL: Email concepts: Email allows the user to send data in the form of text, pictures, sound and video to a remote computer on the internet. These email services are created by companies on specific web services and can be accessed by anyone anywhere in the world at anytime. Some of the familiar servers that offer free email services on the internet are Yahoo, Rediff, Gmail and Hotmail and etc. These three things that you must have to send and receive email An internet email account A connection to the internet A software application that handles email Receiving incoming messages: The incoming messages are received in an email mailbox that resides on a mail server. Depending upon the type of connection that you have, download e-mail from the mail server to your computer or you may read your e-mail from the mail server. Mail server receives and stores email messages in mail boxes by using a protocol called post office protocol 3(POP 3) or internet message access protocol (IMAP) Sending outgoing messages: Write email messages on your computer by using e-mail applications. Then, transfer the messages to an SMTP (simple mail transfer protocol) server, a mail server that accepts outgoing e-mail. The SMTP server that takes care of sending your e-mail messages may be a different server.
Read your email. Deleting messages from the server Your email program usually deletes them from the POP server after downloading. Our applications have a setting that enables you to choose whether to delete the email from the server. Using abbreviations, emoticons, and smiley’s: Emoticons and smiley's Smiley's are punctuations used to conveying mood or emotions in written online communications. Emoticons are used to compensate for the inability to convey voice inflections, facial expressions, and bodily gestures in written communications. Some emoticons are better known as “smiley”. Emotions can be very effective towards avoiding misinterpretation of the writer intents. The most emoticons will look like a face, eyes, nose and mouth. :) Happy :(( Crying :( Sad :)) Laughing ;) wink :-& Sick :-/ Confused [-( Not talking :P Tongue (:| Tired :O Shock @ }:- Rose X-( Angry %% Good luck B-) Cool **== flag Abbreviations used in E-mail: Chat abbreviations are commonly used in e-mail, online chatting online discussion forum postings, instant messaging, and in text messaging, especially between cell phone users. Abbreviations Meaning Abbreviations Meaning AND Any day now CYO See you online AFK Away from keyboard DIKU Do I know you? B4N Bye for now F2F Face to face Read your email. Deleting messages from the server Your email program usually deletes them from the POP server after downloading. Our applications have a setting that enables you to choose whether to delete the email from the server. Using abbreviations, emoticons, and smiley’s: Emoticons and smiley's Smiley's are punctuations used to conveying mood or emotions in written online communications. Emoticons are used to compensate for the inability to convey voice inflections, facial expressions, and bodily gestures in written communications. Some emoticons are better known as “smiley”. Emotions can be very effective towards avoiding misinterpretation of the writer intents. The most emoticons will look like a face, eyes, nose and mouth. :) Happy :(( Crying :( Sad :)) Laughing ;) wink :-& Sick :-/ Confused [-( Not talking :P Tongue (:| Tired :O Shock @ }:- Rose X-( Angry %% Good luck B-) Cool **== flag Abbreviations used in E-mail: Chat abbreviations are commonly used in e-mail, online chatting online discussion forum postings, instant messaging, and in text messaging, especially between cell phone users. Abbreviations Meaning Abbreviations Meaning AND Any day now CYO See you online AFK Away from keyboard DIKU Do I know you? B4N Bye for now F2F Face to face Read your email. Deleting messages from the server Your email program usually deletes them from the POP server after downloading. Our applications have a setting that enables you to choose whether to delete the email from the server. Using abbreviations, emoticons, and smiley’s: Emoticons and smiley's Smiley's are punctuations used to conveying mood or emotions in written online communications. Emoticons are used to compensate for the inability to convey voice inflections, facial expressions, and bodily gestures in written communications. Some emoticons are better known as “smiley”. Emotions can be very effective towards avoiding misinterpretation of the writer intents. The most emoticons will look like a face, eyes, nose and mouth. :) Happy :(( Crying :( Sad :)) Laughing ;) wink :-& Sick :-/ Confused [-( Not talking :P Tongue (:| Tired :O Shock @ }:- Rose X-( Angry %% Good luck B-) Cool **== flag Abbreviations used in E-mail: Chat abbreviations are commonly used in e-mail, online chatting online discussion forum postings, instant messaging, and in text messaging, especially between cell phone users. Abbreviations Meaning Abbreviations Meaning AND Any day now CYO See you online AFK Away from keyboard DIKU Do I know you? B4N Bye for now F2F Face to face
BBN Bye bye now FAQ Frequently ask questions BBS Be back soon GL Good luck CU See you HAGN Have a good night CUL See you later HAND Have a nice day CYA See ya WU? What’s up? FORMATTED E-MAIL: HTML: this is formatted with HTML tags just like web pages. It includes text formatting, numbering, bullets, alignments, horizontal lines, backgrounds, hyperlinks. It is actually sent using the MIME protocol. Rich Text Format: this format can be read by most word processing applications. Documents in this format are also called RTF files. MIME (multipurpose internet mail extensions): it is used for attachments. Formatting includes text formatting, pictures, video and sound. Web based E-mail Advantages: Using web based email we can access the web as well as read our mail. Most web-based e-mail is free. Disadvantages: We can read two kinds of messages on the web. SENDING AND RECEIVING FILES: Attachments: An attachment is a file that has been encoded as text so that it can be included in an e-mail message. The three common ways to encode e-mail attachments are: MIME- Multipurpose Internet Mail Extension is the standard method. Unencoding- this method is supported by some older e-mail applications. BBN Bye bye now FAQ Frequently ask questions BBS Be back soon GL Good luck CU See you HAGN Have a good night CUL See you later HAND Have a nice day CYA See ya WU? What’s up? FORMATTED E-MAIL: HTML: this is formatted with HTML tags just like web pages. It includes text formatting, numbering, bullets, alignments, horizontal lines, backgrounds, hyperlinks. It is actually sent using the MIME protocol. Rich Text Format: this format can be read by most word processing applications. Documents in this format are also called RTF files. MIME (multipurpose internet mail extensions): it is used for attachments. Formatting includes text formatting, pictures, video and sound. Web based E-mail Advantages: Using web based email we can access the web as well as read our mail. Most web-based e-mail is free. Disadvantages: We can read two kinds of messages on the web. SENDING AND RECEIVING FILES: Attachments: An attachment is a file that has been encoded as text so that it can be included in an e-mail message. The three common ways to encode e-mail attachments are: MIME- Multipurpose Internet Mail Extension is the standard method. Unencoding- this method is supported by some older e-mail applications. BBN Bye bye now FAQ Frequently ask questions BBS Be back soon GL Good luck CU See you HAGN Have a good night CUL See you later HAND Have a nice day CYA See ya WU? What’s up? FORMATTED E-MAIL: HTML: this is formatted with HTML tags just like web pages. It includes text formatting, numbering, bullets, alignments, horizontal lines, backgrounds, hyperlinks. It is actually sent using the MIME protocol. Rich Text Format: this format can be read by most word processing applications. Documents in this format are also called RTF files. MIME (multipurpose internet mail extensions): it is used for attachments. Formatting includes text formatting, pictures, video and sound. Web based E-mail Advantages: Using web based email we can access the web as well as read our mail. Most web-based e-mail is free. Disadvantages: We can read two kinds of messages on the web. SENDING AND RECEIVING FILES: Attachments: An attachment is a file that has been encoded as text so that it can be included in an e-mail message. The three common ways to encode e-mail attachments are: MIME- Multipurpose Internet Mail Extension is the standard method. Unencoding- this method is supported by some older e-mail applications.
If you select the Open it option the appropriate application will start and open the file. Selecting Save it to disk will open the Save As dialog box enabling you to save the file to disk. Try to always use the Save it to disk option, as this decreases the risk of a virus entering your computer. Click on the OK button Here are 13 useful tips to save your computer from email bugs and viruses. These steps are especially useful for those who use Microsoft Outlook or any other software like Thunder Bird as an email client.
- File Deleting Viruses: A File Deleting Virus is designed to delete critical files which are the part of Operating System or data files. - Mass Mailer Viruses: Mass Mailer Viruses search e-mail programs like MS outlook for e-mail addresses which are stored in the address book and replicate by e-mailing themselves to the addresses stored in the address book of the e-mail program. - Macro viruses: Macro viruses are written by using the Macro programming languages like VBA, which is a feature of MS office package. A macro is a way to automate and simplify a task that you perform repeatedly in MS office suit (MS Excel, MS word etc). These macros are usually stored as part of the document or spreadsheet and can travel to other systems when these files are transferred to another computers. - Polymorphic Viruses: Polymorphic Viruses have the capability to change their appearance and change their code every time they infect a different system. This helps the Polymorphic Viruses to hide from anti-virus software. - Armored Viruses: Armored Viruses are type of viruses that are designed and written to make itself difficult to detect or analyze. An Armored Virus may also have the ability to protect itself from antivirus programs, making it more difficult to disinfect. - Stealth viruses: Stealth viruses have the capability to hide from operating system or anti-virus software by making changes to file sizes or directory structure. Stealth viruses are anti-heuristic nature which helps them to hide from heuristic detection. - Polymorphic Viruses: Polymorphic viruses change their form in order to avoid detection and disinfection by anti-virus applications. After the work, these types of viruses try to hide from the anti-virus application by encrypting parts of the virus itself. This is known as mutation. - Retrovirus: Retrovirus is another type virus which tries to attack and disable the anti-virus application running on the computer. A retrovirus can be considered anti- antivirus. Some Retroviruses attack the anti-virus application and stop it from running or some other destroys the virus definition database. Multiple Characteristic viruses: Multiple Characteristic viruses have different characteristics of viruses and have different capabilities - File Deleting Viruses: A File Deleting Virus is designed to delete critical files which are the part of Operating System or data files. - Mass Mailer Viruses: Mass Mailer Viruses search e-mail programs like MS outlook for e-mail addresses which are stored in the address book and replicate by e-mailing themselves to the addresses stored in the address book of the e-mail program. - Macro viruses: Macro viruses are written by using the Macro programming languages like VBA, which is a feature of MS office package. A macro is a way to automate and simplify a task that you perform repeatedly in MS office suit (MS Excel, MS word etc). These macros are usually stored as part of the document or spreadsheet and can travel to other systems when these files are transferred to another computers. - Polymorphic Viruses: Polymorphic Viruses have the capability to change their appearance and change their code every time they infect a different system. This helps the Polymorphic Viruses to hide from anti-virus software. - Armored Viruses: Armored Viruses are type of viruses that are designed and written to make itself difficult to detect or analyze. An Armored Virus may also have the ability to protect itself from antivirus programs, making it more difficult to disinfect. - Stealth viruses: Stealth viruses have the capability to hide from operating system or anti-virus software by making changes to file sizes or directory structure. Stealth viruses are anti-heuristic nature which helps them to hide from heuristic detection. - Polymorphic Viruses: Polymorphic viruses change their form in order to avoid detection and disinfection by anti-virus applications. After the work, these types of viruses try to hide from the anti-virus application by encrypting parts of the virus itself. This is known as mutation. - Retrovirus: Retrovirus is another type virus which tries to attack and disable the anti-virus application running on the computer. A retrovirus can be considered anti- antivirus. Some Retroviruses attack the anti-virus application and stop it from running or some other destroys the virus definition database. Multiple Characteristic viruses: Multiple Characteristic viruses have different characteristics of viruses and have different capabilities - File Deleting Viruses: A File Deleting Virus is designed to delete critical files which are the part of Operating System or data files. - Mass Mailer Viruses: Mass Mailer Viruses search e-mail programs like MS outlook for e-mail addresses which are stored in the address book and replicate by e-mailing themselves to the addresses stored in the address book of the e-mail program. - Macro viruses: Macro viruses are written by using the Macro programming languages like VBA, which is a feature of MS office package. A macro is a way to automate and simplify a task that you perform repeatedly in MS office suit (MS Excel, MS word etc). These macros are usually stored as part of the document or spreadsheet and can travel to other systems when these files are transferred to another computers. - Polymorphic Viruses: Polymorphic Viruses have the capability to change their appearance and change their code every time they infect a different system. This helps the Polymorphic Viruses to hide from anti-virus software. - Armored Viruses: Armored Viruses are type of viruses that are designed and written to make itself difficult to detect or analyze. An Armored Virus may also have the ability to protect itself from antivirus programs, making it more difficult to disinfect. - Stealth viruses: Stealth viruses have the capability to hide from operating system or anti-virus software by making changes to file sizes or directory structure. Stealth viruses are anti-heuristic nature which helps them to hide from heuristic detection. - Polymorphic Viruses: Polymorphic viruses change their form in order to avoid detection and disinfection by anti-virus applications. After the work, these types of viruses try to hide from the anti-virus application by encrypting parts of the virus itself. This is known as mutation. - Retrovirus: Retrovirus is another type virus which tries to attack and disable the anti-virus application running on the computer. A retrovirus can be considered anti- antivirus. Some Retroviruses attack the anti-virus application and stop it from running or some other destroys the virus definition database. Multiple Characteristic viruses: Multiple Characteristic viruses have different characteristics of viruses and have different capabilities
Computer virus can slow down your computer. Might corrupt your system files. Might make some programs faulty or corrupt Might damage your boot sector creating problems when you boot into the windows. Might steal important information from your computer and send to some other person. Might change the power ratings of your computer and could blast the system CHATTING AND CONFERENCING ON THE INTERNET: Online chatting, messaging, and conferencing concepts Online chatting or online conferencing enables internet users to exchange text or to have discussions with groups of people in real time. The groups of people involved may be anywhere in the world. This group communication can take the form of text, voice, or video, and messages and responses can be changed. FORMS OF CHAT, MESSAGING AND CONFERENCING Real time chat: Each participant sees each message with seconds of when it is sent, and the reply is given quickly. However, all participants need to be online at a same time.
Computer virus can slow down your computer. Might corrupt your system files. Might make some programs faulty or corrupt Might damage your boot sector creating problems when you boot into the windows. Might steal important information from your computer and send to some other person. Might change the power ratings of your computer and could blast the system CHATTING AND CONFERENCING ON THE INTERNET: Online chatting, messaging, and conferencing concepts Online chatting or online conferencing enables internet users to exchange text or to have discussions with groups of people in real time. The groups of people involved may be anywhere in the world. This group communication can take the form of text, voice, or video, and messages and responses can be changed. FORMS OF CHAT, MESSAGING AND CONFERENCING Real time chat: Each participant sees each message with seconds of when it is sent, and the reply is given quickly. However, all participants need to be online at a same time.
Computer virus can slow down your computer. Might corrupt your system files. Might make some programs faulty or corrupt Might damage your boot sector creating problems when you boot into the windows. Might steal important information from your computer and send to some other person. Might change the power ratings of your computer and could blast the system CHATTING AND CONFERENCING ON THE INTERNET: Online chatting, messaging, and conferencing concepts Online chatting or online conferencing enables internet users to exchange text or to have discussions with groups of people in real time. The groups of people involved may be anywhere in the world. This group communication can take the form of text, voice, or video, and messages and responses can be changed. FORMS OF CHAT, MESSAGING AND CONFERENCING Real time chat: Each participant sees each message with seconds of when it is sent, and the reply is given quickly. However, all participants need to be online at a same time.
