❑ COW is resource management technique.
❑ It means copying the original data when the data being shared is modified.
❍ Example 1. (Fork) If the shared data is in the memory area of the parent process, memory is not allocated for the child process. But if the shared data of the parent process changes, memory is allocated for the child process.
❍ Example 2. (Programing) If a variable y is assigned to the variable x(x=y), they use the same buffer, but when the x or y changes, they use different buffers.