Disk Defragmentation Simulator

Selected drive

System (C:) Hard disk drive · NTFS (simulated)

Capacity

500 GB

Used

0 GB

Free

0 GB

Status

Needs analysis

Sample disk state

Animation

Optimisation speed 2×

Cluster map 864 clusters

Disk map key

Coloured blocks = file data

Light blocks = free clusters

Amber = cluster being moved

Green = destination cluster

HDD only: this simulator demonstrates file defragmentation on a mechanical hard disk. SSDs are normally optimised using TRIM/retrim rather than this kind of block rearrangement.

Optimize Drives Analyse and optimise your simulated drive

SIMULATOR

Drive

Media type

Last run

Current status

System (C:)

Hard disk drive

Never

Needs analysis

Fragmented files

of 0 files

File fragments

contiguous runs

Fragmentation

files fragmented

Cluster moves

during this run

Largest free run

clusters together

Cluster map Each colour represents a different file.

A fragmented sample disk is ready.

Analyse the drive to measure fragmentation, then choose Optimize to rearrange file clusters into contiguous runs.

What is happening

Fragmented disk ready

Files have been deliberately split into separate runs across the disk. Analyse the drive to see how fragmented it is.

Current operation Waiting for Analyse or Optimize.

Key idea: a fragmented file is stored in more than one non-contiguous run of clusters.

Currently consolidating No file selected

—clusters

—fragments

—placed

Why defragment an HDD?

Mechanical read/write head

When pieces of the same file are far apart, the head may need more seeks. Making file extents more contiguous can reduce that movement for sequential access.

Illustrative seek overheadHigh

Live analysis

Used space0 GB

Free space0 GB

Contiguous files0

Optimisation0%

Accuracy & scope

Teaching model: real defragmenters use operating-system and file-system APIs and do not necessarily move clusters in exactly this visible order. This simulator accurately demonstrates the key effect: fragmented file extents are consolidated so files occupy fewer, longer contiguous runs, while free space becomes more consolidated.