1.5.6 Utility Software : Data Compression & backup

Question 1

Data Compression Software - Compression

Answer 1

Compression utilities reduce the amount of disk space needed to store a file by applying a lossless compression algorithm.
Lossless compression means that no quality is lost from the original file, and it can be restored to the original.

Question 2

Data Compression Software - Uses of Compression

Answer 2

Although we cannot read compressed files without decompressing them first, they are useful in many situations. For example:
When a file won’t be accessed regularly e.g. in archives.
When a file is to be transferred on a network (to speed up transfer).

Question 3

Data Compression Software - Decompression

Answer 3

Compression utilities can also decompress the compressed files to return them to their original versions.
Files must be decompressed in order to read them.

Question 4

Backup Software - Purpose of Backup Software

Answer 4

Backup software creates a copy of important data, so that it can be stored in an external location.
Having multiple copies of the data means that if something happens to one of the copies, we can restore it using another.

Question 5

Backup Software - Full backup

Answer 5

A full backup describes when a copy is made of everything on the system onto the backup media.
Full backups are slow processes and take up a lot of space.
It is very easy to restore a system from a full backup.

Incremental backup

Question 6

Backup Software - Incremental backup

Answer 6

An incremental backup is when you copy just the files that have changed since the last backup.
Incremental backups are faster and use less space.
It’s more difficult to restore a system from incremental backups because:
The most recent full backup must be applied.
Every incremental backup since then must then be applied in the correct order.