Process and Threads

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Process and Threads by Mind Map: Process and Threads

1. Process Termination

1.1. include HALT instruction or explicit OS service call for termination

2. Five-State Process Model

2.1. New

2.1.1. A process is being created.

2.2. Ready

2.2.1. A process that as prepared to be executed when given chance.

2.3. Blocked

2.3.1. A process that cannot execute until some event s occur, such as I/O completion.

2.4. Running

2.4.1. A process that is currently being executed.

2.5. Exit

2.5.1. A process that has finished its execution.

2.6. Suspend

2.6.1. A process that has been swapped out of main memory.

3. Suspended Processes

3.1. Swapping

3.1.1. moving parts of all of a process from main memory to disk

3.2. one suspend state

3.3. Characteristics

3.3.1. not available immediately to run

3.3.2. process placed in suspend state to prevent execution

3.3.3. process may or may not wait for an event

3.3.4. process may not be removed until agent explicitly orders the removal

4. Processes and Threads

4.1. Resource ownership

4.1.1. include a virtual address space to hold process image

4.2. Scheduling/Execution

4.2.1. follow an execution path that may interleaved with others

4.3. Thread

4.3.1. a basic unit of CPU utilization

4.3.2. also known as lightweight process

4.4. Multithreading

4.4.1. the ability of an OS to support multiple, concurrent paths of execution within a single process

4.5. resource ownership

4.5.1. process

4.5.2. task

5. Single Threaded Approaches

5.1. the concept of a thread is not recognized

6. Multithreaded Approaches

6.1. a system of one process with multiple threads

7. Processes

7.1. Unit of resource allocation and unit of protection

7.2. Virtual address space holds process image

8. Benefits of threads

8.1. lesser time to create new thread than process

8.2. lesser time to terminate a thread than process

8.3. switching between two threads takes lesser time compare to process

8.4. threads enhance efficiency in communications among programs

9. OS management of application execution

9.1. resources are able to multiple applications

9.2. processor switched among multiple applications

9.3. Process

9.3.1. a program in execution

9.3.2. Active entity with a program counter specifying the next instruction to be executed

9.4. Program

9.4.1. Passive entity such as contents of a file stored on disk

10. Process Elements

10.1. Program Code

10.1.1. shared with other process that using same program

10.2. A set of data associated

11. Process Control Block

11.1. Contains the process element

11.2. Created and managed by the operating system

11.3. interrupt a running process and resume later

12. Process States

12.1. Trace

12.1.1. listing the sequence of instructions that execute for that process

12.1.2. show how traces of processes are interleaved

12.2. Dispatcher

12.2.1. switches the processor from one process to another

13. Two-State Process Model

13.1. Running

13.1.1. the process is currently being executed

13.2. Not running

14. Process Creation

14.1. Process spawning

14.1.1. OS creates a process at the explicit request of another process

14.2. occurs when a new process is added to those currently being managed processes

14.3. Parent process

14.3.1. original process

14.4. OS build data structures to manage the process and allocates address space in main memory

14.5. Child process

14.5.1. new process

15. One or more threads in a process

15.1. an execution state

15.2. saved thread context when not running

15.3. an execution stack

15.4. some per-thread static storage for local variables

15.5. access to memory and resources

16. Operating System Control Structure

16.1. manage processes and resources

16.2. construct and maintains information

16.3. Types of tables by OS

16.3.1. memory tables

16.3.2. IO tables

16.3.3. File tables

16.3.4. Process tables