System Components

• Operating systems Process Management

The operating system is responsible for the following activities in connection with process management.

-->Process creation and deletion.

-->Process suspension and resumption.

-->Provision of mechanisms for:

-->Process synchronization

->Process communication

• Main memory management
  Memory management is the act of managing computer memory. In its simpler forms, this involves providing ways to allocate portions of memory to programs at their request, and freeing it for reuse when no longer needed. The management of main memory is critical to the computer system.
  Virtual memory systems separate the memory addresses used by a process from actual physical addresses, allowing separation of processes and increasing the effectively available amount of RAM using disk swapping. The quality of the virtual memory manager can have a big impact on overall system performance.
  Garbage collection is the automated allocation, and deallocation of computer memory resources for a program. This is generally implemented at the programming language level and is in opposition to manual memory management, the explicit allocation and deallocation of computer memory resources.

• File management Also referred to as simply a file system or filesystem. The system that an operating system or program uses to organize and keep track of files. For example, a hierarchical file system is one that uses directories to organize files into a tree structure. Although the operating system provides its own file management system, you can buy separate file management systems. These systems interact smoothly with the operating system but provide more features, such as improved backup procedures and stricter file protection.
  

• I/O System management

The I/O system consists of:

-->A buffer-caching system

-->A general device-driver interface

-->Drivers for specific hardware devices

• Secondary Storage System
  Secondary storage management is a classical feature of database management systems. It is usually supported through a set of mechanisms. These include index management, data clustering, data buffering, access path selection and query optimization.
  None of these is visible to the user: they are simply performance features. However, they are so critical in terms of performance that their absence will keep the system from performing some tasks (simply because they take too much time). The important point is that they be invisible. The application programmer should not have to write code to maintain indices, to allocate disk storage, or to move data between disk and main memory. Thus, there should be a clear independence between the logical and the physical level of the system.
  
  
  
  
• Protection System

Protection refers to a mechanism for controlling access by programs, processes, or users to both system and user resources.
The protection mechanism must:

-->Distinguish between authorized and unauthorized usage.

-->Specify the controls to be imposed.

-->Provide a means of enforcement.

• Command-Interpreter System
  A command-line interpreter (also command line shell, command language interpreter) is a computer program that reads lines of text entered by a user and interprets them in the context of a given operating system or programming language.