Explain the concept of shared memory and in what cases it is used.

Shared memory is a region of memory that is accessible simultaneously by multiple processes or threads for data exchange without the need for slower channels, such as sockets or files.

It is used in cases where high-speed data exchange between processes is required, for example:

• Inter-process communication (IPC) in operating systems.
• Sharing large volumes of data without copying.
• Implementing caching or buffers accessible to multiple applications.

Example: two processes can open the same shared memory segment and read/write data directly, which is much faster than exchanging through files or network.

It is important to consider synchronization of access (mutexes, semaphores) to avoid race conditions and data corruption.