Some Terminology
Program: executable file on disk
Process: executing instance of a program
Process ID: unique, non-negative integer identifier (a handle by which to refer to a process)
UNIX kernel: a C program that implements a general interface to a computer to be used for writing programs (p6)
System call: well-defined entry point into kernel, to request a service
UNIX technique: for each system call, have a function of same name in the standard C library
- user process calls this function
- function invokes appropriate kernel service