A-Level Computingdata damage and prevention

Objectives•To know the dangers associated with a

computer system

•To understand the methods of prevention

•To be able to demonstrate the need for prevention methods

Privacy & Security•What can cause damage to a computer

system?

Privacy & Security•Accidental & Malicious Damage

•Hardware failure - all hardware dies eventually.

•Software Failure - programming bugs

•Human Errors - hanging of data or deletion of files

•Malicious Damage - angry employee, a virus or a hacker.

Privacy & Security•Any loss or corruption of data will have

serious or fatal implications for the performance of the application

•Delays, loss of business and possible legal action may result.

Privacy & Security•What can you do to prevent damage to

your computer system

Privacy & Security•Physical security

•Security Guards

•Alarms

•Locks

•Swipe/ID Cards

•Read/Write Tabs

Privacy & Security•In order to gain access to the system a

user is supplied with a user name together with a personal password.

•Operating system will check the user name and password are valid before allowing the user to log in.

•Some files may be open by anyone, others only by those users with a particular level of access.

Privacy & Security•The file itself has attributes that can be

set. The commonly used ones in Windows are:

•Read-only - the file can be read but not altered

•Hidden - the file is not displayed in listings of files.

Privacy & Security•Computers connected to networks -

especially the Internet - need to be protected from hackers.

•Firewalls are software methods of blocking access to anyone from outside a network unless they are authorised.

Privacy & Security•To maintain file security when data is

transferred from one computer to another the data can be encrypted.

•This means that the data is encoded in some way before it is sent, and therefore meaningless to anyone intercepting the message.

•The data is then decoded at the receiving end by the user who knows the way to decrypt it (often referred to as the key).

Privacy & Security•Key - next letter along in alphabet:

•IFMMP XPSME

•HELLO WORLD

•Data encryption can also be used when data is stored on a file. A hacker accessing the data will find it meaningless unless he has the key.

Privacy & Security•Important files of data should be

regularly backed up - this means making another copy of the data and storing the copy in a different place.

•Many organisations run a daily backup - scheduled to run overnight, but backups can be done any time.

•Backups may be stored on the same computer - but it is better to store them on a different one.

Privacy & Security•Backups of data may also be stored on

backing storage media such as CD, DVD or tape cartridge.

•The backup copies should be stored securely - a locked room or a fire-proof safe.

•As broadband Internet access becomes more widespread, backups to remote sites are becoming more popular.

Privacy & Security•If data is accidentally or deliberately

lost or damaged, the backup data should be loaded.

•All changes to the data since the backup was made will need to be done again.