Final answer:
The fastest form of interprocess communication in UNIX is shared memory, which allows multiple processes to access the same memory area for quick and efficient data exchange without frequent system calls.
Step-by-step explanation:
The fastest form of interprocess communication provided in UNIX is Shared Memory. Interprocess communication (IPC) refers to the mechanisms an operating system provides to allow processes it manages to share data. Typically, applications can use IPC categorized as message passing, semaphores, and shared memory. Each of these has its use cases, but when considering speed, shared memory is generally the fastest method because it allows multiple processes to access the same memory area.
Processes can communicate with each other without invoking the kernel via system calls after the initial setup. They read and write to the shared memory space just as they would their local variables in their process space, which means the overhead is minimized, leading to faster communication. While shared memory is quick, developers must carefully synchronize access to avoid race conditions and ensure data integrity.