1. Backup Procedure  To prevent against data loss, computer users should have backup procedures  A backup is a copy of information stored on a computer.  Additional resources or duplicate copies of data on different storage media for emergency purposes.  Backup procedures specify a regular plan of copying and storing key data and programs files *

2. Backup types  Full backup  Differential backup  Incremental backup  And some more  http://technet.oracle.com/doc/server.81 5/a67773/rmanconc.htm#440395 http://technet.oracle.com/doc/server.81 5/a67773/rmanconc.htm#440395  http://www.techweb.com/encyclopedia/ defineterm.yb?term=backup%20types http://www.techweb.com/encyclopedia/ defineterm.yb?term=backup%20types

3. Full backup  Backs up all selected files. Master Data Primary dataBackup data Master Data

4. Differential backup  Backs up selected files that have been changed. This is used when only the latest version of a file is required. Full Backup SunTueMon 11 2 …… Sat 1 2 …… 6

5. Differential backup  Only full backup (Sun) and the latest differential backup (Sat) are required to restore the files  More space required than incremental backup strategy  Backup operation is slower than incremental backup  Faster restore  Keep only the latest differential backup between 2 full backups

6. Incremental backup  Backs up selected files that have been changed, but if a file has been changed for the second or subsequent time since the last full backup, the file doesn't replace the already-backed-up file, rather it is appended to the backup medium. This is used when each revision of a file must be maintained  Save space  Faster backup  Must keep all incremental backups between 2 full backups  Restore/recovery operation is slower

7. Incremental backup  The full backup and all incremental backups are required to restore the files Full Backup SunTueMon 12 …… Sat 6

8. Computer Viruses  A virus is a piece of programming code inserted into other programming codes to cause some unexpected and, for the victim, usually an undesirable event  Viruses can be transmitted by downloading program from other sites or be present on a diskette  http://www.techweb.com/encyclopedia/defi neterm.yb?term=virus&x=37&y=12 http://www.techweb.com/encyclopedia/defi neterm.yb?term=virus&x=37&y=12  http://whatis.techtarget.com/wsearchResult s/1,290214,sid9,00.html?query=virus http://whatis.techtarget.com/wsearchResult s/1,290214,sid9,00.html?query=virus *

9. Symptoms of virus infection  Destruction of computer files, file allocation table, information stored in CMOS, hard disk partition table, boot sectors of disk and interference of computer screen  Some act quickly. They erase user programs and database  Some act slowly. They gradually destroy small parts of a database every day  Other viruses act like a time bomb, e.g. the Michaelangelo virus contaminates the machine on Michaelangelo's birthday. *

10. Prevention of computer viruses  know the origin of each program or file that you load into your computer –buy anti-virus software that typically checks all of your files periodically and can remove any viruses that are found –Avoid using disks or checking e-mail that contain executable programs from a doubtful source –Whenever you use a floppy disk, scan it with an anti-virus program –To prevent infection through networks, only allow authorised users access, e.g. use passwords –Use an anti-virus program to scan all downloaded materials *

11. Reference URLs  HP products, services & support in automated backup –http://www.automatedbackup.com http://www.automatedbackup.com  Window NT backup & restore –http://www.oreilly.com/catalog/backup http://www.oreilly.com/catalog/backup  Memory write, computer backups –http://www.bc-biz.com/memorywritehttp://www.bc-biz.com/memorywrite  Symantec--internet security technology –http://www.norton.com http://www.norton.com *

12.  Trend Micro Inc. – provider of tools to detect and block viruses, malicious code and related internet security threats –http://www.antivirus.com http://www.antivirus.com  Borderware – no risk e-business –http://www.borderware.de http://www.borderware.de  Computer Association has provided free anti-virus program for downloading –www.cai.comwww.cai.com *