Contiguous allocation in Operating Systems - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is contiguous allocation in operating systems?

Contiguous allocation is a method of storing files where each file occupies a set of consecutive blocks on the disk. This means the file's data is stored in one continuous area.

beginner

What is a major advantage of contiguous allocation?

It allows fast access to files because the disk head can read the file in one continuous sweep without moving to different locations.

intermediate

What is a common problem caused by contiguous allocation?

It can cause external fragmentation, where free space is broken into small pieces scattered around the disk, making it hard to find large enough continuous space for new files.

intermediate

How does contiguous allocation affect file size changes?

If a file grows beyond its allocated space, it may need to be moved to a larger continuous space, which can be inefficient and slow.

intermediate

Name one alternative to contiguous allocation to avoid its drawbacks.

Linked allocation or indexed allocation are alternatives that store file blocks non-contiguously, reducing fragmentation and allowing easier file size changes.

What does contiguous allocation require for storing a file?

A Linked list of blocks

B Random scattered blocks

C A set of consecutive disk blocks

D Indexed blocks

Contiguous allocation stores files in consecutive disk blocks to allow fast sequential access.

Which problem is most associated with contiguous allocation?

A Internal fragmentation

B External fragmentation

C Slow access speed

D File corruption

External fragmentation happens when free space is split into small pieces, making it hard to allocate large continuous blocks.

Why might a file need to be moved in contiguous allocation?

A Because it grows beyond its allocated space

B Because it is deleted

C Because it is compressed

D Because it is encrypted

If a file grows larger than its allocated continuous space, it must be moved to a bigger continuous area.

Which of these is NOT an advantage of contiguous allocation?

A No fragmentation

B Simple to implement

C Fast sequential access

D Easy to calculate file location

Contiguous allocation suffers from external fragmentation, so 'No fragmentation' is incorrect.

Which allocation method stores file blocks non-contiguously to reduce fragmentation?

A Contiguous allocation

B Direct allocation

C Sequential allocation

D Linked allocation

Linked allocation stores file blocks scattered but linked, reducing fragmentation problems.

Explain how contiguous allocation works and why it can cause fragmentation.

Think about how files are placed on disk and what happens when space is limited.

Describe one advantage and one disadvantage of contiguous allocation.

Consider speed and space management.