This is a simple slide on Processes of Operating system.

1. Topic:
Processes
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2. Process
• Program that is in execution.
• More than the program code
• Has several parts
• Text Section- Contains the code of the program.
• Stack- Contains Temporary data(Function parameters, local var, Return
address).
• Data Section- Contains Global var
• Heap- Contains dynamic memory allocated during process run time.
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3. Process State
• New- The process is being created.
• Ready- All the resources are
available, process is waiting to be
assigned to a processor
• Running- The CPU is working on this
process's instructions.
• Waiting- The process is waiting for
some event to occur (such as an I/O
completion or reception of a signal).
• Terminated- The process has
finished execution.
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4. Process or Task Control Block
Process is represented in the operating system by a
process control block. Contains many information of a
specific process including these:
• Process State - Ready, Running, waiting, etc.
• Process Number – Process number and parent process
ID.
• Program counter - Indicates the address of the next
instruction to be executed for this process.
• Registers - This state information must be saved when
an interrupt occurs, to allow the process to be
continued correctly in further process.
• List of open files - It saves device allocated, open file
tables, etc.
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5. Process Scheduler & Context Switching
Operating system uses a program scheduler to schedules the processes
of computer system
• LTS - Selects process from job pool and loads them into memory.
• STC - Selects among the processes that are ready to execute.
Context Switching: Saves the current PCB and switch into next PCB. This
task is known as a context switch. Happens by interrupt or some higher
priority task.
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