In what cases is copy-on-write technology used?

The copy-on-write (COW) technology is used to optimize memory usage and data storage. The main idea is that when copying an object (such as a file or a memory block), a full copy is not created immediately; instead, a reference to the original data is made. Actual copying occurs only when one of the copies attempts to modify the data.

Examples of use:

• In file systems (e.g., APFS on iOS) for creating snapshots without duplicating data.
• When working with virtual memory, where processes share the same memory pages until a write occurs.
• In version control systems for storing changes without duplicating the entire file.

This allows saving resources and increasing performance, especially when working with large volumes of data.