1. Chapter 1: Introduction

2. Chapter 1: Introduction
What Operating Systems Do
Computer-System Organization
Operating-System Structure
Operating-System functionalities
Process Management
Memory Management
Storage Management
Protection and Security
Computing Environments

3. Objectives To understand the computer system organization
To understand the major operating system components

4. What is an Operating System? (user view)

5. What is an Operating System? (user view) OS
For ease of use

6. What is an Operating System? (system view)
output
CPU
data
MEM

7. What is an Operating System? (system view)
output
CPU
data
MEM
prog1
prog2
prog3
prog4
Control program
Resource allocator

8. Computer-system operation (The OS initialization phase)
ROM 1 2
RAM 3

9. Computer-System Organization (after booting)
applications
Sys. call
signal OS
cmd
Hardware
polling
interrupt

10. OS operations I/O devices and the CPU execute concurrently AP1
applications
I/O devices and the CPU execute concurrently
AP1
AP2
AP2
Sys. call
signal OS 1
cmd 4 3
interrupt
buffer 2
controller

11. Common Functions of Interrupts (interrupt vector table, IVT)
mem
Interrupt transfers control to the interrupt service routine
Disable all incoming interrupts (???)
Save the CPU status of the interrupted program
IDTR 1 2’
ISR 2”
IDTR: interrupt descriptor table register

12. Common Functions of Interrupts
applications
Software interrupt
Sys. call
signal
OS kernel
cmd
Hardware
polling
interrupt
Basically, an operating system is interrupt driven.
Dual-Mode operation: kernel mode + user mode

13. Interrupt Handling
Save the CPU status (including the CPU status register, program counter and some other registers)
Interrupt handling depends on the type of interrupt
polling
vectored interrupt system
vectored interrupt system + polling
Execute the interrupt service routine.

14. Direct Memory Access Structure (DMA)
bus

15. Direct Memory Access Structure (DMA)
cache
bus

16. Two I/O Methods
After I/O starts, control returns to user program only upon I/O completion.
Synchronous I/O
Cons:???
Pros:???
After I/O starts, control returns to user program without waiting for I/O completion.
Asynchronous I/O

17. Two I/O Methods
Synchronous
Asynchronous

18. Storage Hierarchy Storage systems organized in hierarchy.
Speed
Cost
Volatility
Caching – a temporary storage area where frequently accessed data can be stored for rapid access.
Register: main memory
Cache memory: main memory
Main memory: disk

19. Storage-Device Hierarchy
compiler OS
only large storage media that the CPU can access directly.
extension of main memory that provides large nonvolatile storage capacity. 刪掉

20. Performance of Various Levels of Storage
(OS)

21. Cache (Coherency & consistency)
L1 $
L1 $
L2 $
L2 $
bus

22. Operating System Structure
Multiprogramming needed for efficiency
Server
When CPU has to wait (for I/O for example), OS switches to another program
Timesharing (multitasking) creates interactive computing
Personal computer
+ programs exhaust their time slice

23. Multiprogramming
CPU
I/O
ready
CPU
ready
CPU
I/O
time

24. Timesharing
CPU
ready
CPU
I/O
CPU
ready
CPU
ready
CPU
I/O
time

25. Operating-System Operations
applications
AP1
AP2
AP2
Sys. call
int_ret OS 1
cmd 4 3
interrupt
buffer 2
controller

26. Dual-mode operation AP1 applications AP2 AP2 User mode Sys. call
Int_ret
Kernel mode OS 1
cmd 4 3
interrupt
buffer 2
controller

27. Dual-mode operation applications trap AP2 User mode Kernel mode OS
Syscall_handler
ISR
CPU
Mode=kernel_mode
Push PC
Save machine status
Jump_to ISR
Exception
:= Trap
:= Software interrupt

28. Dual-mode operation AP1 applications AP2 AP2 User mode Sys. call
Int_ret
Kernel mode OS
Syscall_handler 1
cmd 4 3
interrupt
buffer 2
controller

29. Dual-mode operation applications trap AP2 AP2 User mode Kernel mode OS
Syscall_handler
ISR
CPU
restore machine status
Mode=user_mode
Pop PC

30. Timer time CPU ready CPU I/O CPU ready CPU ready CPU I/O timer
interrupt
time
timer

31. OS OS Structure Protec-tion Process manage-ment Memory manage-ment
setuid…
SELinux OS
Protec-tion
Process manage-ment
Memory manage-ment
Storage manage-ment
security
passwd…
fork…
open & close…
malloc..

32. Computing Environments (symmetric multiprocessor, SMP)
CPU 0
CPU 1
CPU 2
bus

33. Computing Environments (chip multiprocessor, CMP)
CPU
Core 0
Core 1
L1 $
L1 $
L2 $
bus

34. Computing Environments (simultaneously multithreading, SMT)
CPU
Core
Logical processor 0
Logical processor 1
L1 $
L2 $
bus

35. Computing Environments (CMP+SMT)
CPU
Core 0
Core 1
LP0
LP1
LP0
LP1
L1 $
L1 $
L2 $
bus

36. Computing Environments (symmetric multiprocessor, SMP) (UMA)
CPU 0
CMP+SMT
CPU 1
CMP+SMT
CPU 2
CMP+SMT
bus

37. Computing Environments (symmetric multiprocessor, SMP) (NUMA)
CPU 0
CMP+SMT
CPU 1
CMP+SMT
CPU 2
CMP+SMT
bus

38. Embedded systems & web computing
internet
WEB apps

39. 參考資料
Silberschatz, Galvin and Gagne, “Operating system Principles,” 8th ed
Wikipedia,