What is the main purpose of disk defragmentation in Windows?

The main purpose of disk defragmentation in Windows is to improve performance by reorganizing fragmented data. When files are written to a disk, they can become fragmented, meaning that the pieces of a single file are stored in various locations on the disk rather than being contiguous. This happens because the system does not always have enough contiguous space to store the entire file in one place.

Defragmentation reorganizes the data on the disk so that related file pieces are stored together in a single, contiguous block. This leads to reduced read and write times, as the disk head can access and read files more quickly without having to move to different locations to gather all parts of a file. Consequently, this process enhances overall system performance and efficiency.

The other options focus on different aspects unrelated to defragmentation. Backing up system data, increasing internet speed, and uninstalling programs are all valid maintenance tasks but do not involve the reorganization of disk data to enhance performance.