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 *

Backup types  Full backup  Differential backup  Incremental backup  And some more  5/a67773/rmanconc.htm# /a67773/rmanconc.htm#  defineterm.yb?term=backup%20types defineterm.yb?term=backup%20types

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

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

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

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

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

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  neterm.yb?term=virus&x=37&y=12 neterm.yb?term=virus&x=37&y=12  s/1,290214,sid9,00.html?query=virus s/1,290214,sid9,00.html?query=virus *

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. *

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 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 *

Reference URLs  HP products, services & support in automated backup –  Window NT backup & restore –  Memory write, computer backups –  Symantec--internet security technology – *

 Trend Micro Inc. – provider of tools to detect and block viruses, malicious code and related internet security threats –  Borderware – no risk e-business –  Computer Association has provided free anti-virus program for downloading – *