Process and Threads

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Process and Threads by Mind Map: Process and Threads

1. OS management of application execution

1.1. resources are able to multiple applications

1.2. processor switched among multiple applications

1.3. Process

1.3.1. a program in execution

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

1.4. Program

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

2. Process Elements

2.1. Program Code

2.1.1. shared with other process that using same program

2.2. A set of data associated

3. Process Control Block

3.1. Contains the process element

3.2. Created and managed by the operating system

3.3. interrupt a running process and resume later

4. Process States

4.1. Trace

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

4.1.2. show how traces of processes are interleaved

4.2. Dispatcher

4.2.1. switches the processor from one process to another

5. Two-State Process Model

5.1. Running

5.1.1. the process is currently being executed

5.2. Not running

6. Process Creation

6.1. Process spawning

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

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

6.3. Parent process

6.3.1. original process

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

6.5. Child process

6.5.1. new process

7. Process Termination

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

8. Five-State Process Model

8.1. New

8.1.1. A process is being created.

8.2. Ready

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

8.3. Blocked

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

8.4. Running

8.4.1. A process that is currently being executed.

8.5. Exit

8.5.1. A process that has finished its execution.

8.6. Suspend

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

9. Suspended Processes

9.1. Swapping

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

9.2. one suspend state

9.3. Characteristics

9.3.1. not available immediately to run

9.3.2. process placed in suspend state to prevent execution

9.3.3. process may or may not wait for an event

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

10. Processes and Threads

10.1. Resource ownership

10.1.1. include a virtual address space to hold process image

10.2. Scheduling/Execution

10.2.1. follow an execution path that may interleaved with others

10.3. Thread

10.3.1. a basic unit of CPU utilization

10.3.2. also known as lightweight process

10.4. Multithreading

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

10.5. resource ownership

10.5.1. process

10.5.2. task

11. Single Threaded Approaches

11.1. the concept of a thread is not recognized

12. Multithreaded Approaches

12.1. a system of one process with multiple threads

13. Processes

13.1. Unit of resource allocation and unit of protection

13.2. Virtual address space holds process image

14. One or more threads in a process

14.1. an execution state

14.2. saved thread context when not running

14.3. an execution stack

14.4. some per-thread static storage for local variables

14.5. access to memory and resources

15. Operating System Control Structure

15.1. manage processes and resources

15.2. construct and maintains information

15.3. Types of tables by OS

15.3.1. memory tables

15.3.2. IO tables

15.3.3. File tables

15.3.4. Process tables

16. Benefits of threads

16.1. lesser time to create new thread than process

16.2. lesser time to terminate a thread than process

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

16.4. threads enhance efficiency in communications among programs