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24 Cards in this Set
- Front
- Back
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Viruses |
Pose the biggest threat under the heading malicious damage. A virus is a program that replicates itself automatically and usually carries with it some payload which causes damage. |
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Trojans |
A program that performs a legitimate task but also carries with it an undesirable function. |
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Worms |
A program that keeps replicating itself automatically and as it does so it takes more and more disk space and also uses a greater proportion of the system's resources for each copy. |
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How can viruses be spread? |
- external/internal email - the organisations intranet - shared disk - banner advertisements - downloads |
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How can viruses be prevented? |
- up-to-date virus checking software - do not open emails from unknown sources - have a clear acceptable use policy - train staff to be aware of the problems |
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Backup |
Keeping copies of software and data so that the data can be recovered should there be a total loss of the ICT system. |
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Where should you keep backups? |
It is always best to keep backups off site but this is sometimes inconvenient. If inconvenient, they should be kept in a fireproof safe or online. |
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Procedures for backup: |
- Use a different tape or disk each day and have a system for rotating them - Make one person responsible for the taking of backups - Keep backups safe and preferably off site - Rehearse backup recovery procedures |
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Backup strategy |
- What - When - How - Storage |
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What |
- Decide what needs to be backed up - e.g. data and programs |
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What are the different types of backup? |
- full backup - incremental backup - differential backup |
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Full backup |
Involves making a copy of all the files on the system. |
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Incremental backup |
Backs up the files which have changed since the last full backup. Useful because it it possible to have an audit trail of the file changes. |
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Differential backup |
A cumulative backup of changes made since the last full backup. |
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When |
How often backups are taken depends on how much data changes and how often it changes. |
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Individuals |
- Backups need to be taken regularly and not just when you remember - Many people take backups at the end of a session of work - Not so many people bother to make backups of media such as music, images and video mainly because of the time it takes |
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Organisations |
- Employ computer professionals who realise that the risk of losing data is real - More systematic - Taken at the end of the day or more frequently depending on the volume of work - Taken in the evening when the processing power is not needed for other tasks |
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How |
Depends on the amount of storage capacity needed and if there is the requirement for the data to be recovered immediately. |
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Backup storage devices and media |
- Storage capacity needed - Portability of device/media - Speed of data transfer - Speed of access - Ability to be connected to different computers or other devices |
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Magnetic tape |
An ideal backup medium - it is cheap and has a high storage capacity. They are removable media which means they can be exchanged with any compatible drive. |
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Magnetic disk |
Takes the contents of one magnetic disk and copies it onto a different magnetic disk. |
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Optical media |
Includes CD-ROM, CD-RW etc. The main problem with optical storage for backup is that the transfer rate is low, which means taking backups takes longer. |
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Pen/flash drives |
Very popular as they are small and portable and are ideal for backing up small amounts of work. They are easily lost or stolen. |
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Recovery procedures |
- Alternative accommodation should the building be destroyed - Availability of staff at short notice - Availability of hardware to run the backups on - Training for staff to instruct them how to get things back to normal again - Availability of alternative communication lines |
