Operating Systems - Process Scheduling Quick Revision Notes

• Process: 

1. It is a program in execution. 
2. It is a unit of work in the modern time sharing system
3. A process is of two types: 1. Operating System Process: It executes system code 2. User Process: It executes user code.

• A process includes: 

1. Program Code (text section)
2. Current Activity (Represented by value of program counters and content of registers of process
3. Process Stack (contains temporary data)
4. Data Section (Global variable)

• Difference between a process and a program: 

A program is a passive entity (Example: contents of file stored in a disk) whereas a process is an active entity (has a program counter specifying next activity to execute). 

• Process State: It is defined by the current activity part of process. Note: Only one process can be in running state.

• Process Control Block: Each project is represented in Operating System using PCB (Process control block or task control block).

To be Continued...