OS X and iOS Kernel Programming

Operating System Services

With a modern operating system, there is a clear separation between the functions performed by the operating system and the functions performed by the application. Whenever a process wishes to perform a task such as allocating memory, reading data from disk, or sending data over a network, it needs to go through the operating system using a set of well-defined programming interfaces that are provided by the system. System functions such as malloc() and read() are examples of system calls that provide operating system services. These system calls may be made directly by the application or indirectly through a higher-level development framework such as the Cocoa framework on Mac OS X. Internally, the Cocoa framework is ...