A system call is a CPU instruction that signals the operating system to do something. This is usually something that regular processes don’t have permission to do. Normal processes can’t start deleting files on your hard drive for example. Typically this is to write or read a file for example.
Uses
In CPSC 213, you will see how to use system calls to open files or applications. Effectively, they are assembly level instructions that order the operating system to perform an action. Whether the operating system honors that request or not is dependent on a bunch of different factors, that usually involve some level of privilege.
You won’t have to know too much about it for CPSC 213, but these specific instructions are used.
