Components of Operating Systems





Process Management:

Providing multiple processes allows conceptually concurrent processing, assisting with modularisation of the program.

The OS provides for creation, deletion, suspension, resumption of processes.
Processes often require synchronisation and communication with each other - the OS must provide facilities for this.

As multiple processes wish to share resources, resource allocation is required.

With this come problems of deadlock and starvation which must be treated.



Memory Management:

The aim of memory management is to allow processes to use as much as possible of the memory, whilst giving each as much as it requires.

The operating system is responsible for allocating memory to processes, and keeping track of free memory.

Segmentation and/or paging may be implemented. Segmentation avoids internal fragmentation, paging avoids external fragmentation.

Virtual memory uses secondary memory to emulate main memory.




File Management:

The objective of the file system is to provide a user-friendly interface to a large structured persistent storage area.

The file system usually has a directory structure. A directory is a file which contains information about the location of other files.

The file system provides facilities to manipulate files and directories.


Input/Output Management:

The objective of I/O system management is to provide controlled (non-interfering) convenient access to I/O devices.

Efficiency is improved by buffering, caching and spooling.

Device drivers are low-level software interfaces to devices.