file descriptors

File descriptors are like labeled access points that operating systems use to manage how programs read from or write to files and data streams. Think of them as numbered hooks that connect applications to resources such as files, network connections, or devices, enabling smooth data transfer. When a program opens a file, the OS assigns it a file descriptor, allowing subsequent operations (like reading or writing) to reference this number for efficient communication. This system simplifies resource management and supports multitasking by keeping track of multiple active data streams concurrently.