The Great Symbian

Program execution – system capability to load a program into memory and to run it.

I/O operations – since user programs cannot execute I/O operations directly, the operating system must provide some means to perform I/O.

File-system manipulation – program capability to read, write, create, and delete files.

Communications – exchange of information between processes executing either on the same computer or on different systems tied together by a network. Implemented via shared memory or message passing.

Error detection – ensure correct computing by detecting errors in the CPU and memory hardware, in I/O devices, or in user programs.


Additional functions exist not for helping the user, but rather for ensuring efficient system operations.
•Resource allocation – allocating resources to multiple users or multiple jobs running at the same time.
•Preemptable, nonpreemptable resources
•Deadlock prevention and detection models
•Accounting – keep track of and record which users use how much and what kinds of computer resources for account billing or for accumulating usage statistics.
•Protection – ensuring that all access to system resources is controlled.