System Calls

• Programming interface to the services provided by the OS
• Typically written in a high-level language (C or C++)
• Mostly accessed by programs via a high-level Application Programming Interface (API) rather than direct system call use
• Three most common APIs are Win32 API for Windows,
• POSIX API for POSIX-based systems (including virtually all versions of UNIX, Linux, and Mac OS X)
• Java API for the Java virtual machine (JVM)