1. Fundamental of Computer Architecture By Panyayot Chaikan panyayot@coe.psu.ac.th 240-208 September 13, 2004

2. Chapter 9- Operating System support 2 240-208 Fundamental of Computer Architecture Chapter 9 การสนับสนุน ระบบปฏิบัติการ Operating System support

3. Chapter 9- Operating System support 3 240-208 Fundamental of Computer Architecture เนื้อหา การสนับสนุนการทำ multitasking ของซีพียูและ ระบบฮาร์ดแวร์ - Program Relocation - Memory protection - Timer interrupt - Dual-mode operation of CPU ระบบหน่วยความจำเสมือน (Virtual Memory)

4. Chapter 9- Operating System support 4 240-208 Fundamental of Computer Architecture Multitasking-Operating System  Supported by most OSs  Windows(98, NT, 2000, XP), Linux, OS/2, AIX, System7, Solaris, UNIX, etc.  Easy to use  Increment CPU utilization  Need HW support

5. Chapter 9- Operating System support 5 240-208 Fundamental of Computer Architecture Multitasking :hardware support  Dual-Mode Operation  Program relocation  Memory protection  Timer interrupts

6. Chapter 9- Operating System support 6 240-208 Fundamental of Computer Architecture Dual-mode Operation  Needed to protect the OS from improper behavior of application programs  CPU must provide at least 2 modes of operation  Monitor mode  User mode  OS runs in monitor mode only  Application runs in user mode only

7. Chapter 9- Operating System support 7 240-208 Fundamental of Computer Architecture Monitor mode  Sometimes called Privileged mode or System mode  Used by OS only  Allow Privileged instructions to be executed  When interrupt or trap occurs, the CPU automatically switched to monitor mode

8. Chapter 9- Operating System support 8 240-208 Fundamental of Computer Architecture User mode  Used by application program  Do not allow Privileged instructions to be executed  OS switch the CPU to user- mode before running application  Trap to OS when privileged instruction are tried to be executed by application program

9. Chapter 9- Operating System support 9 240-208 Fundamental of Computer Architecture Program relocation

10. Chapter 9- Operating System support 10 240-208 Fundamental of Computer Architecture Memory protection

11. Chapter 9- Operating System support 11 240-208 Fundamental of Computer Architecture Memory protection hardware

12. Chapter 9- Operating System support 12 240-208 Fundamental of Computer Architecture Case stydy: memory protection/relocation in CDC6600

13. Chapter 9- Operating System support 13 240-208 Fundamental of Computer Architecture Timer interrupt  OS need to ensure that each application get CPU time equally  OS set value in Timer before switch to run application  While the application is running, value in timer is decreased every clock cycle  when value in Timer reach 0, the CPU is interrupted by Timer

14. Chapter 9- Operating System support 14 240-208 Fundamental of Computer Architecture Timer of PC

15. Chapter 9- Operating System support 15 240-208 Fundamental of Computer Architecture Timer of PC

16. Chapter 9- Operating System support 16 240-208 Fundamental of Computer Architecture Virtual memory  Provide programmer’s point of view that the system has unlimited memory  Makes programming easier, overlay is no longer needed  The program can be run in the system that has limited physical memory

17. Chapter 9- Operating System support 17 240-208 Fundamental of Computer Architecture What is Overlay?

18. Chapter 9- Operating System support 18 240-208 Fundamental of Computer Architecture Virtual memory : Demand Paging

19. Chapter 9- Operating System support 19 240-208 Fundamental of Computer Architecture TLB and Virtual memory

20. Chapter 9- Operating System support 20 240-208 Fundamental of Computer Architecture TLB of Athlon processor

21. Chapter 9- Operating System support 21 240-208 Fundamental of Computer Architecture จบ บทที่ 9