Encryption software; Defragmentation; Data compression

Utility system software: Encryption software; Defragmentation; Data compression

1.5.2 Utility software

Utility software — Note 2 of 2

What you need to know

Three key types of utility software are encryption software (protecting data), defragmentation software (reorganising fragmented files), and data compression software (reducing file sizes).

What to know

Defragmentation is ONLY useful for HDDs (magnetic drives with moving read/write heads). SSDs do NOT need defragmentation because they can access any location equally fast.
Fragmentation occurs over time as files are created, modified, and deleted — pieces of files become scattered across the disk.

Key terms

Exam tipCommon mistake

Encryption Software: Uses complex algorithms to encrypt data, making it unreadable without the correct decryption key. Can encrypt specific files or an entire hard disk.
Exam tip: Encryption software uses a KEY (not a 'lock') to scramble data. If the data is intercepted, it cannot be UNDERSTOOD. Note: encryption does not STOP interception.
Defragmentation Software: Reorganises files on a hard disk drive so that file fragments are stored together in contiguous blocks, improving access speed.
Data Compression Software: Reduces file sizes so they take up less storage space and can be transmitted more quickly.

Exam technique

Tip:Defragmentation improves HDD performance by reducing the distance the read/write head needs to travel. It is NOT needed for SSDs.
Mistake:Saying defragmentation works on SSDs. SSDs have no moving parts, so fragmentation does not affect their performance.
Tip:Defragmentation moves files to be CONSECUTIVE/CONTIGUOUS in storage and collects free space together. The read head does not need to move as far → faster access. It does NOT create more storage space.
Tip:After defrag, SAVING new files is also faster because free space is grouped together, so new files can be stored without splitting.

Example:'Explain how fragmentation occurs in a restaurant ordering system' — orders are saved then deleted; new orders may be bigger than the deleted spaces; files get split up and stored in non-contiguous locations.

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