Which System call should be made to communicate with device driver program of a device?

The correct answer is ioctl().

Key Points

• ioctl() is a system call used to communicate with device driver programs and perform operations that are not provided by standard system calls.
• This system call allows user-space programs to send control or configuration commands to devices via their drivers.
• ioctl() is particularly useful for performing device-specific input/output operations or configuring hardware settings.
• It takes three arguments: a file descriptor, a request code, and an optional argument (typically a pointer to data).
• Commonly used in scenarios involving hardware control, such as setting network interface parameters, controlling device-specific operations, or querying device status.

Additional Information

• The open() system call is used to open files or device nodes, but it does not handle device-specific operations.
• fork() creates a new process and is unrelated to device communication.
• sleep() temporarily suspends a program for a specified duration and is also unrelated to device communication.
• Device drivers often define custom ioctl() commands to allow users to interact with specific device functionality.
• System calls like read() and write() handle data transfer but lack the capability to control or configure devices.