List components of OS. Explain process management in detail








List of System Components: 
1. Process management 

2. Main memory management
 
3. File management

 4. I/O system management 

5. Secondary storage management 


Process Management: 
The operating system manages many kinds of activities ranging from user programs to system programs like printer spooler, name servers, file server etc. Each of these activities is encapsulated in a process. 

 A process includes the complete execution context (code, data, PC, registers, OS resources in use etc.).
  The basic unit of software that the operating system deals with in scheduling the work done by the processor is either a process or a thread, depending on the operating system. 
 It’s tempting to think of a process as an application, but that gives an incomplete picture of how processes relate to the operating system and hardware.
  The application you see (word processor or spreadsheet or game) is, indeed, a process, but that application may cause several other processes to begin, for tasks like communications with other devices or other computers. 
 There are also numerous processes that run without giving you direct evidence that they ever exist. A process, then, is software that performs some action and can be controlled by a user, by other applications or by the operating system. 
 It is processes, rather than applications, that the operating system controls and schedules for execution by the CPU. In a singletasking system, the schedule is straightforward. 
 The operating system allows the application to begin running, suspending the execution only long enough to deal with interrupts and user input. 
 The five major activities of an operating system in regard to process management are

 1. Creation and deletion of user and system processes. 
2. Suspension and resumption of processes. 
3. A mechanism for process synchronization.
 4. A mechanism for process communication. 
5. A mechanism for deadlock handling.