2. Welcome to CMPE003 Personal Computer Concepts: Hardware and Software Winter 2003 UC Santa Cruz Instructor: Guy Cox

3. 8/16/2015 Assignments Details on the class web page:  http://www.soe.ucsc.edu/classes/cmpe003/Winter03/ http://www.soe.ucsc.edu/classes/cmpe003/Winter03/ TAs  Chunxiao Zhou (chunxiao@soe.ucsc.edu)chunxiao@soe.ucsc.edu  Dat Nguyen (dhnguyen@cats.ucsc.edu)dhnguyen@cats.ucsc.edu Sections  Monday – 4 – 6 PM, Oakes #205  Tuesday – 4 – 6 PM, Oakes #205  Friday – 10 – 12 AM, Oakes #205

4. 8/16/2015 2 nd Homework: Due January 22, 2003 Web Search Exercise See class web page for details http://www.soe.ucsc.edu/classes/cmpe003/Winter03/

5. 8/16/2015 Objectives of Chapter 2 Describe the functions of an Operating System Explain the basics of a personal computer operating system Describe the advantages of a graphical operating system Differentiate among different operating systems Explain the need for network operating systems Describe the methods of resource allocation on large computers Be able to describe the differences among multiprocessing, multiprogramming, and timesharing Explain the principles of memory management List several functions typically performed by utility programs

6. 8/16/2015 Types of OS’s Interface  Command Line, GUI Single User  PC, MAC Multi-user  UNIX, Linux, Mainframe (Proprietary) Network(ed) Operating System (NOS)

7. 8/16/2015 MS-DOS Command-line interface – ala UNIX Prompt – system is waiting for you to do something Type in a command Not user-friendly

8. 8/16/2015 Microsoft Windows Graphical user interface Eases access to the OS Most new computers come with Windows already installed

9. 8/16/2015 GUI (Graphical User Interface) Aka WIMP interface  Windows, Icons, Menus, Pointer On-screen pictures  Icons  Menus Pull down Pop up  Click to activate a command or function Fast and Easy Intuitive (usually)

10. 8/16/2015 Early Days of Windows Operating environment for MS-DOS Shell – layer added between users and DOS

11. 8/16/2015 Windows Today Home/consumer market  Windows 95  Windows 98  Windows Millennium Edition (ME) Corporate market  Windows NT  Windows 2000 Windows XP Pocket computers and Internet appliances  Windows CE

12. 8/16/2015 Windows 95 and 98 Self-contained OS DOS commands still available Start programs by  Start button  Double clicking the icon Task bar permits movement between open programs Long file names up to 255 characters Plug and play Object linking and embedding (OLE)

13. 8/16/2015 Windows 98 Additions Internet / intranet browsing Support for DVD and additional multimedia components Support for large hard drives TV viewer and broadcast ability Wizards

14. 8/16/2015 Improved Windows Features Backup Interfaces with other software Networking features Security Dr. Watson

15. 8/16/2015 Windows ME: Millennium Edition Multimedia support -- Windows Media Player 7 Jukebox  Record music CDs as digital files Windows Movie Maker  Basic video editing Windows Image Acquisition  Scanner and digital camera

16. 8/16/2015 Windows NT: New Technology Engineered for stability Strong security Versions  NT Workstation  NT Server Drawbacks  Lacks support for older Windows and MS-DOS software and hardware  Complex to learn and use  Requires more memory and processing power

17. 8/16/2015 Windows 2000 Stability features Security features Uses simple approach to hardware setup from Windows 98 Versions  Windows 2000 Professional for individual users  Windows 2000 for network servers Was intended for both the corporate and home use, replacing Win NT and Win 98

18. 8/16/2015 Windows 2000 Complex Heavy demand for computer resources Improvements over windows NT  Maintains user preferences  Self-healing applications software  Supports Windows 98 file structure  Uses plug and play  Provides improved support for laptops

19. 8/16/2015 Windows XP Extends Windows ME and provides a more stable environment Two categories  Network server 3 versions based upon network complexity  Desktop computer 2 versions  Professional Client  Personal Client

20. 8/16/2015 Windows CE: Consumer Electronics Subset of Windows Less memory Smaller screens Little or no file storage Provides Internet connectivity

21. 8/16/2015 Windows CE: Consumer Electronics Where used Embedded systems  Industrial controllers  Robots  Office equipment  Cameras  Telephones  Home entertainment devices  Automobile navigation systems Pocket PC Internet appliance market

22. 8/16/2015 Accessibility Options Seeing Hearing Touching

23. 8/16/2015 Mac OS (Apple Computer) First commercially successful GUI (1984) Served as a model to other GUI systems

24. 8/16/2015 UNIX Supports  Multi-user  Time-sharing Character-based system Command-line interface GUI: X-Windows Runs on various processors and many types of platforms Primary OS used on Internet servers

25. 8/16/2015 Free BSD A Free, public domain version of Berkeley UNIX Open source software  GNU General Public License  Download it free www.freebsd.org  Make changes and use freely XFree86 GUI included PC Setup  PC comes with Windows installed  Install FreeBSD in a dual-boot configuration (or reformat drives and use only FreeBSD)

26. 8/16/2015 LINUX UNIX-like OS Open-source software  Download it free  Make changes  Distribute copies  Restriction – any changes must be made freely available to the public PC Setup  PC comes with Windows installed  Install LINUX in a dual-boot configuration

27. 8/16/2015 UNIX (FreeBSD, LINUX, etc) Advantages over Windows  Extremely stable  Internet support designed in from the beginning UC Berkeley had early TCP/IP Unix distribution  Reinstallation is simpler Disadvantage  Scarcity of applications for new toys

28. 8/16/2015 Networked Operating Systems (NOS) Designed to permit computers on a network to share resources Examples  Windows 2000 Server  Novell Net Ware  UNIX – NFS… Provides  Data security  Troubleshooting  Administrative control

29. 8/16/2015 NOS Functions Split between client and server computers Server  File management Client  Requests to the server  Messaging  Has own local OS Makes the resources appear as if they are local to the client’s computer

30. 8/16/2015 Large Computer OS Used by many people at once OS works “behind the scenes” so users can share OS must control  Who gets access to resources  What keeps the programs from different users from getting mixed up with one another

31. 8/16/2015 Recall… Functions of OS Manage the computer’s resources  CPU  Memory  Disk drives  Printers Establish a user interface Executes and provides services for applications software Carries out all input and output operations

32. 8/16/2015 What is an OS? Machine/resource manager. Physical Devices Microarchitecture Instruction Set Architecture Operating System Utilities, Editors, etc. Hardware Application programs

33. 8/16/2015 Resource Allocation Resource – hardware or software that is needed to complete a task Resource Allocation – assigning computer resources to certain programs Resource De-allocation – releasing resources when a task is complete

34. 8/16/2015 Deadlocks Shared data/resource may lead to deadlock: processes get “stuck”. Example: v is using r1 and requests r2; w is using r2 and requests r1. wv r1r2

35. 8/16/2015 Allocating the CPU One CPU  Multiprogramming (aka Multitasking) Event-driven Timesharing More than one CPU  Multiprocessing – multiple CPUs can run several programs simultaneously  SMP – Symmetrical Multi-Processing

36. 8/16/2015 Multiprogramming One CPU Concurrent execution of two or more processes  Several processes open at once  Only one process can receive the attention of the CPU at any given moment  Effective because CPU speeds are many times faster than input/output speeds

37. 8/16/2015 Event-driven Multiprogramming One program receives the attention of the CPU Its processing will be interrupted based upon events in the program When processing needs to be temporarily suspended, an interrupt is generated This is a signal to the operating system to evaluate the cause of the interrupt and determine who should now have CPU time

38. 8/16/2015 Event-driven Multiprogramming Example Two programs are running – Payroll and Inventory Management Payroll needs to read an employee record Payroll generates an interrupt to read from the disk Normal processing is temporarily suspended The CPU looks at the interrupt and initiates the read operation on the disk drive While waiting for the read to complete, the CPU begins processing the Inventory Management program

39. 8/16/2015 Event-driven Multiprogramming Example When the disk read operation is complete, another interrupt is generated Normal processing is temporarily suspended The CPU looks at the interrupt and determines its cause (read the data in from the disk drive for the Payroll program) The CPU will either continue processing the Inventory Management program or return to the Payroll program depending upon their priority

40. 8/16/2015 Time-sharing Multiprogramming One program receives the attention of the CPU A small fraction of CPU time is allocated to the program The time slice ends The CPU begins processing a different program Response time can vary based upon the number of users on the system

41. 8/16/2015 Sharing Memory Program must be in memory to be executed Problems  Programs compete for space  May have a very large program  Memory space for each program must not overlap

42. 8/16/2015 Memory Management The process of providing separate memory space to programs Memory Protection keeps one program from interfering with another

43. 8/16/2015 Memory Management: Methods Partitions or regions Foreground and background Virtual storage (virtual memory)

44. 8/16/2015 Partitions or Regions Divide memory into sections (i.e., partitions) The partition must accommodate the largest possible program Problem  May cause wasted memory space

45. 8/16/2015 Foreground and Background Programs are placed in either Foreground or Background Programs in Foreground have priority for CPU time While performing read / write operations for the Foreground program, the CPU gives time to a program in Background Programs are placed in a holding queue while waiting to run

46. 8/16/2015 Virtual Storage: Virtual Memory Uses concept of Paging Divide the program into equal-size pieces (pages) Store each piece in equal-size memory spaces (page frames) Typical size is 2KB or 4KB Create an index to each page and store in a Page Table

47. 8/16/2015 Paging Process A portion of the program is placed in memory The remainder is on disk Sections on disk will be brought into memory as needed (one page at a time) Virtual Storage: Virtual Memory

48. 8/16/2015 Virtual Storage: Virtual Memory Problem -- Thrashing  A large portion of CPU time is spent swapping the correct page and bringing it into memory Solution  Run fewer programs concurrently  Add memory  Program design “working set” size – number of pages required in memory for program to run

49. 8/16/2015 Memory Protection Keeps one program from straying into another Confines each program to certain defined limits in memory Why needed  Possible for one program to destroy or modify another by transferring to the wrong memory location  May cause destruction of data Action if assigned memory space is violated  Termination of executing program

50. 8/16/2015 Sharing Storage Several users need to access the same disk pack  One wants to write  Another wants to read OS keeps track of the I/O requests OS processes I/O requests in order received

51. 8/16/2015 Sharing Printing Resources Print resources are shared between active programs Printouts are generated in pieces as the CPU gives each concurrent program some time Problem  The current program may generate a few print lines  The CPU moves to the next program  The second program may generate a few print lines, etc.

52. 8/16/2015 Sharing Printing Resources Result  Printout is worthless as it contains a few lines from several programs Solution – Spooling  Each program thinks it is writing to the printer  The program actually writes to the hard disk  When the program is complete, the file on the hard disk is sent to the printer

53. 8/16/2015 Additional Printing Problem Printers are slow compared to the CPU speed Solution  The CPU writing to the disk  The program completes quicker

54. 8/16/2015 Utility Programs Come with System Software Handle special needs Perform secondary chores Do not need to be memory resident

55. 8/16/2015 Functions of Utility programs File manager – provide access to lists of stored files Backup and Restore – make duplicate copies of important files and return the copy to the hard drive if needed File compression – reduces the amount of disk space required by a file Disk defragmenter – reorganize files so they are stored contiguously on disk providing for faster access Device drivers – convert operating system instructions into commands that are known to a specific device

56. 8/16/2015 Next…. Chapter 3 (Friday) “Applications Software: Getting the Work Done” Chapter 4 (Wednesday) “The Internet: A Resource for All of Us”