Threads allow concurrency within a process by separating the execution state (program counter, registers, stack) from the process. This allows a process to have multiple execution streams (threads) that can run independently while sharing the process's resources like memory. Key benefits of threads include improved responsiveness, easy resource sharing between threads, and better utilization of multiprocessor systems.

1. Chapter 4: Threads

10. Single and Multithreaded Processes

12. Thread Design Space address space thread one thread/process many processes many threads/process many processes one thread/process one process many threads/process one process MS/DOS Java older UNIXes Mach, NT, Chorus, Linux, …

13. (old) Process address space 0x00000000 0x7FFFFFFF address space code (text segment) static data (data segment) heap (dynamic allocated mem) stack (dynamic allocated mem) PC SP

14. (new) Address space with threads 0x00000000 0x7FFFFFFF address space code (text segment) static data (data segment) heap (dynamic allocated mem) thread 1 stack PC (T2) SP (T2) thread 2 stack thread 3 stack SP (T1) SP (T3) PC (T1) PC (T3) SP PC

15. Types of Threads

22. Threading Issues

33. OS Examples