Unix Basics Practice Test: System Calls Basics — Flashcards

Unix system calls
System calls are the way that a process communicates with the operating system kernel. They provide a way for processes to request services from the kernel, such as reading and writing files, creating and managing processes, and accessing hardware devices.
System calls are typically implemented as functions that are exported by the kernel. When a process makes a system call, it traps into the kernel, which then executes the requested operation. Once the operation is complete, the kernel returns control to the process.
There are many different system calls available in Unix, each of which provides a different service to processes. 

Some of the most common system calls include:
open(): : Opens a file for reading or writing.
read(): : Reads data from a file.
write(): : Writes data to a file.
close(): : Closes a file.
fork(): : Creates a new process.
exec(): : Executes a new program.
exit(): : Terminates a process.