1. Operating Systems Principles Lecture 1: Introduction
主講人：虞台文

2. Content The Role of Operating Systems
Bridge the Hardware/Application Gap
Three Views of Operating Systems
Organization of Operating Systems
Structural Organization
The Hardware Interface
The Programming Interface
The User Interface
Runtime Organization
Operating System Evolution & Concepts

3. Operating Systems Principles Lecture 1: Introduction
The Role of Operating Systems

4. PC Hardware Organization

5. Users ←→ Hardware
The Gap

6. Users ←→ Hardware The Gap
User needs to think in terms of problem to be solved
High-level data structures and corresponding operations
Simple, uniform interfaces to subsystems,
Treat programs and data files as single entities
Hardware capabilities are very low level
Arithmetic and logical operators
Comparison of two bit-strings
Branching, reading, and writing bytes
The Gap

7. Fills the Gap
Software

8. Fills the Gap Software Use software to bridge this gap
Language processors e.g.,
- assemblers, compilers, interpreters
Editors and text processors, linkers and loaders.
Application programs, utility and service programs.
Operating Systems
Software

9. Single CPU System

10. Single CPU System

11. I/O Devices
I/O Devices

12. Multiprocessor Systems
Share-Memory Model
Distributed-Memory Model

13. Synchronization & Communication of CPU’s
Share-Memory Model
Distributed-Memory Model
through the shared memory
interconnection network required.

14. Cash Coherence Problem
Cashes do not contain different values for the same memory element.
Share-Memory Model
Distributed-Memory Model
Local Cash

15. Multicomputer System

16. Multicomputer System
Network Controller
Network Controller

17. Local Area Networks
Local area networks (LANs) connect computers within a building or a enterprise network.
LAN network topologies:
Ring Network
Broadcast Bus

18. Wide Area Networks
A Wide Area Network (WAN) is a collection of Local Area Networks (LANs) that have been connected together.
The internet is an example of a WAN.

19. Applications/Services
What are done by OS?
Process Management
Scheduling of process
Synchronization
Memory Management
Virtual memory
Input/Output Systems
Device drivers
Spooling
File Systems
Protection and Security
Applications/Services
Operating
System
Bare
Machine

20. Applications/Services
Three Views of OS’s
Application
Programmer’s View
Applications/Services
Operating
System
User’s View
Bare
Machine
System
Programmer’s View

21. Applications/Services
OS is an extended machine
Abstraction — hides complexity
Provides high level operations
User’s View
Application
Programmer’s View
Applications/Services
Operating
System
User’s View
Bare
Machine
System
Programmer’s View

22. Application Programmer’s View
OS is a virtual machine
Virtualization — supports sharing
Provides virtual CPU, memory, devices
Application Programmer’s View
Application
Programmer’s View
Applications/Services
Operating
System
User’s View
Bare
Machine
System
Programmer’s View

23. System Programmer’s View
OS is a resource manager
Balance overall performance with individual needs
e.g., response time, deadlines
System Programmer’s View
Application
Programmer’s View
Applications/Services
Operating
System
User’s View
Bare
Machine
System
Programmer’s View

24. Operating Systems Principles Lecture 1: Introduction
Organization of Operating Systems

25. Structure Organization of OS
User
Applications
(system & user)
Library
Calls
System
Library
Kernel
Calls
Operating
System
Kernel
Machine
Instructions
Hardware

26. Modes of CPU Execution Hardware User Applications (system & user)
Library
Calls
System
Library
nonprivileged mode
Kernel
Calls
privileged mode
Operating
System
Kernel
Machine
Instructions
Hardware

27. Supervisor Call (SVC) SVC Hardware
SVCs are used to implement all kernel calls and form the basic interface btw the OS kernel and the rest of the software.
Supervisor Call (SVC)
User
Applications
(system & user)
Library
Calls
System
Library
SVC
nonprivileged mode
Kernel
Calls
privileged mode
Operating
System
Kernel
Machine
Instructions
Hardware

28. The Hardware Interface
Applications and OS compiled into machine instructions
Interrupts and Traps allow OS to seize control
process management (time-sharing)
device management (I/O completion)
SVC

29. The Programming Interface
Invoking system services
Library call (nonprivileged)
Kernel call (privileged)

30. The User Interface Text-based shell e.g., Unix, MS Dos
command interpreter
shell scripts
Graphics-based GUI
e.g., Mac, MS Windows
windows
icons
menus
pointer

31. Runtime Organization Service is an Autonomous Process (client-server)
a Subroutine

32. Operating Systems Principles Lecture 1: Introduction
Operating System Evolution & Concepts

33. History of Operating Systems
The First Generation (1945–55)
Vacuum Tubes and Plugboards
The Second Generation (1955–65)
Transistors and Batch Systems
The Third Generation (1965–1980)
ICs and Multiprogramming
The Fourth Generation (1980–Present)
Personal Computers

34. The First Generation (1945–55)  Vacuum Tubes and Plugboards

35. The First Generation (1945–55)  Vacuum Tubes and Plugboards

36. The First Generation (1945–55)  Vacuum Tubes and Plugboards
Machines of the time were so primitive that programs were often entered one bit at time on rows of mechanical switches (plugboards).
Programming languages were unknown (not even assembly languages).
Operating systems were unheard of.

37. The Second Generation (1955–65)  Transistors and Batch Systems
A batch system is one in which jobs are bundled together with the instructions necessary to allow them to be processed without intervention.
Often jobs of a similar nature can be bundled together to further increase economy.

38. The Second Generation (1955–65)  Transistors and Batch Systems

39. The Second Generation (1955–65)  Transistors and Batch Systems
$JOB user_spec ;identify the user for accounting purposes
$FORTRAN ;load the FORTRAN compiler
source program cards
$LOAD ;load the compiled program
$RUN ;run the program
data cards
$EOJ ;end of job
$JOB user_spec ;identify a new user
$LOAD application
$RUN
Data
$EOJ

40. The Second Generation (1955–65)  Transistors and Batch Systems

41. The Second Generation (1955–65)  Transistors and Batch Systems
Monitor: another name of OS.
The Second Generation (1955–65)  Transistors and Batch Systems
Memory Layout of a Batch System
Monitor
(permanently resident)
The monitor is system software that is responsible for interpreting and carrying out the instructions in the batch jobs.
When the monitor started a job, it handed over control of the entire computer to the job, which then controlled the computer until it finished.
User Space
(compilers,
programs,
data, etc.)

42. The Second Generation (1955–65)  Transistors and Batch Systems
Advantages of batch systems
move much of the work of the operator to the computer
increased performance since it was possible for job to start as soon as the previous job finished
Disadvantages
turn-around time can be large from user standpoint
more difficult to debug program
due to lack of protection scheme, one batch job can affect pending jobs (read too many cards, etc)
a job could corrupt the monitor, thus affecting pending jobs
a job could enter an infinite loop

43. The Third Generation (1965–1980)  ICs and Multiprogramming
Have more than one active (running) program in memory at any one time.
Why?

44. The Third Generation (1965–1980)  ICs and Multiprogramming
Main features of this generation
CPU and I/O Overlap
Spooling
simultaneous peripheral operations on line
Time-sharing technique

45. The Third Generation (1965–1980)  ICs and Multiprogramming
The typical CPU and I/O overlap pattern
in a single program

46. The Third Generation (1965–1980)  ICs and Multiprogramming
Goal of multiprogramming 
Keep CPUs and and I/O devices busy.

47. The Third Generation (1965–1980)  ICs and Multiprogramming
CPU Bound Programs
Perform calculation most of time
Scientific computation
I/O Bound Programs
Perform I/O most of time
Commercial data processing

48. The Third Generation (1965–1980)  ICs and Multiprogramming
Time
Saved

49. The Third Generation (1965–1980)  ICs and Multiprogramming
Spooling (simultaneous peripheral operations on line).
In spooling, a high-speed device like a disk interposed between a running program and a low-speed device involved with the program in input/output.
Example: Instead of writing directly to a printer, outputs are written to the disk.
Programs can run to completion faster; and
other programs can be initiated sooner when the printer becomes available, the outputs may be printed.

50. The Third Generation (1965–1980)  ICs and Multiprogramming
Time Sharing Technique
A variant of multiprogramming technique.
Each user has an on-line terminal.
Because the user is present and interacting with the computer, the computer system must respond quickly to user requests, otherwise user productivity could suffer.
Timesharing systems were developed to multiprogram large number of simultaneous interactive users.

51. The Fourth Generation (1980–Present)  Personal Computers
With the development of LSI circuits, chips, operating system entered entered in the personal computer and the workstation age.
Microprocessor technology evolved to the point that it become possible to build desktop computers as powerful as the mainframes of the 1970s.

52. The Fourth Generation (1980–Present)  Personal Computers
CP/M (Control Program of Microcomputers)
MS-Dos
Windows
Unix
GUI

53. The Evolution Early systems  No Operating System
Batch Operating Systems
Multiprogramming Systems
Interactive operating Systems
Personal Computer and Workstation Operating Systems
Real-time Operating Systems
Distributed Operating Systems