Operating System Services Program Development-variety of services and utilities such as Editors and debuggers.They are usually referred to as application program development tools. Program Execution-involves a number of steps,such as loading Instruction and data in the main memory,initialization of l/O devices and files and other resources to be allocated.OS handles the scheduling. .Access to l/O devices-Each I/O device has its own set of Instructions and control signals.O.S.hides these details to provide a common interface to the user/programmer. Operating System Services • Program Development – variety of services and utilities such as Editors and debuggers. They are usually referred to as application program development tools. • Program Execution – involves a number of steps, such as loading Instruction and data in the main memory, initialization of I/O devices and files, and other resources to be allocated. OS handles the scheduling. •Access to I/O devices – Each I/O device has its own set of Instructions and control signals. O.S. hides these details to provide a common interface to the user/programmer