Copy On Write
Copy On Write (COW) is an optimization strategy used in computer programming and operating systems where a copy of a resource (such as memory, file, or data structure) is deferred until it is actually modified. Instead of immediately duplicating data when a copy is requested, the system shares the original resource and only creates a separate copy when a write operation occurs. This approach reduces overhead and improves performance by minimizing unnecessary data duplication, especially in scenarios with frequent read operations and infrequent writes.
Developers should learn and use Copy On Write when implementing systems that require efficient memory management, concurrency, or data sharing, such as in operating systems (e.g., for process forking), databases (e.g., for snapshot isolation), or programming languages (e.g., for immutable data structures). It is particularly valuable in multi-threaded environments or when dealing with large datasets, as it reduces memory usage and copying costs while ensuring data consistency and thread safety during modifications.