1. IT Essentials - Chapter 4 Operating System Fundamentals

2. IT Essentials - Chapter 4 Operating System Fundamentals Operating Systems (OS) are software programs that control thousands of operations, provide an interface between the user and the computer, and run applications. Operating Systems (OS) are software programs that control thousands of operations, provide an interface between the user and the computer, and run applications.

3. IT Essentials - Chapter 4 Operating System Fundamentals Computers that are capable of handling concurrent users and multiple jobs are often called network servers or simply "servers". Servers have operating systems installed called Network Operating Systems (NOS). Computers that are capable of handling concurrent users and multiple jobs are often called network servers or simply "servers". Servers have operating systems installed called Network Operating Systems (NOS).

4. IT Essentials - Chapter 4 Operating System Fundamentals Three basic elements make up the major design components of any operating system. Three basic elements make up the major design components of any operating system.

5. IT Essentials - Chapter 4 Operating System Fundamentals Three basic elements make up the major design components of any operating system. Three basic elements make up the major design components of any operating system. –User interface –Kernel –File management system

6. IT Essentials - Chapter 4 Operating System Fundamentals User interface – A user interacts with the computer OS through the user interface. User interface – A user interacts with the computer OS through the user interface. Simply put, the user interface is the part of the operating system that a person can use to issue commands by either typing them at a command prompt or pointing and clicking the mouse on the screen of a Graphical User Interface (GUI). Simply put, the user interface is the part of the operating system that a person can use to issue commands by either typing them at a command prompt or pointing and clicking the mouse on the screen of a Graphical User Interface (GUI).

7. IT Essentials - Chapter 4 Operating System Fundamentals Kernel – This is the core of the OS. Kernel – This is the core of the OS. The kernel is responsible for loading and running programs (processes) and for managing input and output The kernel is responsible for loading and running programs (processes) and for managing input and output

8. IT Essentials - Chapter 4 Operating System Fundamentals File management system – The file management system is what the OS uses to organize and manage files. File management system – The file management system is what the OS uses to organize and manage files.

9. IT Essentials - Chapter 4 Operating System Fundamentals Operating system functions Operating system functions –File and folder management When a file is saved, the operating system saves it, attaches a name to it, and remembers where it put the file in the hard drive for future use.

10. IT Essentials - Chapter 4 Operating System Fundamentals Operating system functions Operating system functions –Management of applications When a user requests a program, the operating system locates the application and loads it into the primary memory or RAM of the computer.

11. IT Essentials - Chapter 4 Operating System Fundamentals Operating system functions Operating system functions –Support for built-in utility programs Utility programs are programs that the OS uses to maintain and repair itself. These programs help identify problems, locate lost files, repair damaged files, and backup data.

12. IT Essentials - Chapter 4 Operating System Fundamentals Operating system functions Operating system functions –Access control to computer hardware The OS sits between the programs and the Basic Input/Output System (BIOS). All programs that need hardware resources must first go through the operating system. The OS in turn can either access the hardware through the BIOS or through the device drivers.

13. IT Essentials - Chapter 4 Operating System Fundamentals Operating system types Operating system types –Multiuser – Two or more users running programs and sharing peripheral devices, such as a printer, at the same time.

14. IT Essentials - Chapter 4 Operating System Fundamentals Operating system types Operating system types –Multitasking – The capability of a computer to run multiple applications at the same time.

15. IT Essentials - Chapter 4 Operating System Fundamentals Operating system types –Multiprocessing – Allows a computer to have two or more CPUs (Central Processing Unit) that programs share.

16. IT Essentials - Chapter 4 Operating System Fundamentals Operating system types –Multithreading – The capability of a program to be broken into smaller parts that can be loaded as needed by the OS. Multithreading allows individual programs to be multitasked.

17. IT Essentials - Chapter 4 Operating System Fundamentals MS-DOS MS-DOS –DOS is a collection of programs and commands used to control the overall computer operation in a disk-based system. –There are three distinct sections that make up the disk operating system. These include:

18. IT Essentials - Chapter 4 Operating System Fundamentals MS-DOS MS-DOS –Boot files – Used during the boot process (that is, start-up).

19. IT Essentials - Chapter 4 Operating System Fundamentals MS-DOS MS-DOS –Boot files – Used during the boot process (that is, start-up). –File management files – Enables the system to manage the data that it holds.

20. IT Essentials - Chapter 4 Operating System Fundamentals MS-DOS MS-DOS –Boot files – Used during the boot process (that is, start-up). –File management files – Enables the system to manage the data that it holds. –Utility files – Enables the user to manage system resources, troubleshoot the system, and configure the system settings.

21. IT Essentials - Chapter 4 Operating System Fundamentals Elements of DOS Elements of DOS –DOS is a command line operating system, it is not user-friendly. The best way to learn DOS is to use it.

22. IT Essentials - Chapter 4 Operating System Fundamentals Elements of DOS Elements of DOS –DOS is a command line operating system, it is not user-friendly. The best way to learn DOS is to use it. –DOS can only run one program at a time. It is not multitasking.

23. IT Essentials - Chapter 4 Operating System Fundamentals Elements of DOS Elements of DOS –DOS is a command line operating system, it is not user-friendly. The best way to learn DOS is to use it. –DOS can only run one program at a time. It is not multitasking. –DOS can only run small programs and has memory limitations.

24. IT Essentials - Chapter 4 Operating System Fundamentals Elements of DOS Elements of DOS –DOS is a command line operating system, it is not user-friendly. The best way to learn DOS is to use it. –DOS can only run one program at a time. It is not multitasking. –DOS can only run small programs and has memory limitations. –DOS is an essential tool for IT professionals and is used extensively for troubleshooting.

25. IT Essentials - Chapter 4 Operating System Fundamentals Files Files –A file is simply a block of logically related data that is given a single name and treated as a single unit.

26. IT Essentials - Chapter 4 Operating System Fundamentals File Attributes File Attributes –All files have attributes. –These are a set of parameters that describe a file. Given the attributes of a file, it is possible to determine the nature of the file.

27. IT Essentials - Chapter 4 Operating System Fundamentals File Attributes File Attributes –Hidden File – The user will not see this type of file with any kind of normal file search in a DOS environment.

28. IT Essentials - Chapter 4 Operating System Fundamentals File Attributes File Attributes –Hidden File – The user will not see this type of file with any kind of normal file search in a DOS environment. –Read Only – The user can open and read this type of file but cannot write or modify the file in any way.

29. IT Essentials - Chapter 4 Operating System Fundamentals File Attributes File Attributes –Hidden File – The user will not see this type of file with any kind of normal file search in a DOS environment. –Read Only – The user can open and read this type of file but cannot write or modify the file in any way. –Archive (backup) status – Used by backup utilities to determine if a file needs to be backed up or not.

30. IT Essentials - Chapter 4 Operating System Fundamentals File Attributes File Attributes –Hidden File – The user will not see this type of file with any kind of normal file search in a DOS environment. –Read Only – The user can open and read this type of file but cannot write or modify the file in any way. –Archive (backup) status – Used by backup utilities to determine if a file needs to be backed up or not. –System File – A file needed by the DOS operating system for a successful bootup.

31. IT Essentials - Chapter 4 Operating System Fundamentals Internal versus External DOS Commands Internal versus External DOS Commands –Commands that are built into the operating system are internal. –Commands that must be executed from a file are external.

32. IT Essentials - Chapter 4 Operating System Fundamentals Command Line Command Line –the main user interface is the command line. The command line is the space immediately following the DOS prompt.

33. IT Essentials - Chapter 4 Operating System Fundamentals A DOS boot disk is just a floppy disk with three necessary system files on it: A DOS boot disk is just a floppy disk with three necessary system files on it:

34. IT Essentials - Chapter 4 Operating System Fundamentals A DOS boot disk is just a floppy disk with three necessary system files on it: A DOS boot disk is just a floppy disk with three necessary system files on it: COMMAND.COM COMMAND.COM IO.SYS IO.SYS MSDOS.SYS MSDOS.SYS

35. IT Essentials - Chapter 4 Operating System Fundamentals To create a bootable disk… To create a bootable disk… –Insert a blank floppy disk in the drive. –At the command prompt type FORMAT A: /s and press Enter. or

36. IT Essentials - Chapter 4 Operating System Fundamentals To create a bootable disk… To create a bootable disk… –Insert a blank floppy disk in the drive. –At the command prompt type FORMAT A: /s and press Enter. or –If the disk is already formatted, type SYS A: and press Enter.

37. IT Essentials - Chapter 4 Operating System Fundamentals DOS requires these files in this order to boot your system: DOS requires these files in this order to boot your system: –BIOS –bootstrap –io.sys –msdos.sys –config.sys –command.com –autoexec.bat

38. IT Essentials - Chapter 4 Operating System Fundamentals During the boot process, while the MS-DOS message "Starting DOS..." is on, the screen special function keys are available to alter the loading process of CONFIG.SYS (and an option for AUTOEXEC.BAT). During the boot process, while the MS-DOS message "Starting DOS..." is on, the screen special function keys are available to alter the loading process of CONFIG.SYS (and an option for AUTOEXEC.BAT). F5 & F8 F5 & F8

39. IT Essentials - Chapter 4 Operating System Fundamentals –F5 (or Left Shift key) Skips CONFIG.SYS file (including AUTOEXEC.BAT files, if this option is chosen). –F8 Proceeds through the CONFIG.SYS (and AUTOEXEC.BAT, if needed) files one step at a time waiting for Confirmation from the user.

40. IT Essentials - Chapter 4 Operating System Fundamentals SYSEDIT – SYSEDIT – is a standard text editor used to edit system configuration files such as Config.sys and Autoexec.bat.

41. IT Essentials - Chapter 4 Operating System Fundamentals Conventional Memory Conventional Memory 0 and 640KB 0 and 640KB Also known as base memory. Also known as base memory. This is the area where MS-DOS programs normally run. This is the area where MS-DOS programs normally run. In older DOS machines, this is the only memory available for running the OS files, application programs, memory resident routines, and device drivers. Memory-resident routines include Terminate-and-Stay-Resident (TSR) Programs such as mouse and CD-ROM drivers. In older DOS machines, this is the only memory available for running the OS files, application programs, memory resident routines, and device drivers. Memory-resident routines include Terminate-and-Stay-Resident (TSR) Programs such as mouse and CD-ROM drivers.

42. IT Essentials - Chapter 4 Operating System Fundamentals Upper Memory/Expanded Memory Upper Memory/Expanded Memory 640KB to 1024KB 640KB to 1024KB Also known as Reserved Memory. Also known as Reserved Memory. Upper memory is available in the form of Upper Memory Blocks (UMBs). Programs that run here include system BIOS, plug and play BIOS, video BIOS and video RAM. Upper memory is available in the form of Upper Memory Blocks (UMBs). Programs that run here include system BIOS, plug and play BIOS, video BIOS and video RAM. These addresses are only available if an appropriate memory manager such as Emm386.EXE is installed during the startup process. These addresses are only available if an appropriate memory manager such as Emm386.EXE is installed during the startup process.

43. IT Essentials - Chapter 4 Operating System Fundamentals Extended Memory Extended Memory Beyond the 1 MB limit. Beyond the 1 MB limit. Generally referred to as Extended Memory. Generally referred to as Extended Memory. This area of memory is also called Extended Memory Specification (XMS). XMS is the primary memory area used by Windows 9x. A device driver that is loaded by the OS controls this memory area. Windows 9x loads the XMS driver called Himem.sys during startup. Once loaded, Himem.sys makes extended memory available to the Windows 9x and other compatible MS-DOS programs. This area of memory is also called Extended Memory Specification (XMS). XMS is the primary memory area used by Windows 9x. A device driver that is loaded by the OS controls this memory area. Windows 9x loads the XMS driver called Himem.sys during startup. Once loaded, Himem.sys makes extended memory available to the Windows 9x and other compatible MS-DOS programs.

44. IT Essentials - Chapter 4 Operating System Fundamentals High Memory Once the XMS driver is loaded, extended memory becomes available to the OS. When this happens, the first 64KB of extended memory is called the High Memory Area (HMA). High Memory Once the XMS driver is loaded, extended memory becomes available to the OS. When this happens, the first 64KB of extended memory is called the High Memory Area (HMA). Typically, the XMS driver (Himem.sys) activates the DOS=HIGH option, enabling it to copy the MS-DOS kernel used by Windows 9x into the HMA. The point therefore, is that DOS uses the HMA, and by doing so, frees up more conventional memory for use by applications. Typically, the XMS driver (Himem.sys) activates the DOS=HIGH option, enabling it to copy the MS-DOS kernel used by Windows 9x into the HMA. The point therefore, is that DOS uses the HMA, and by doing so, frees up more conventional memory for use by applications.

45. IT Essentials - Chapter 4 Operating System Fundamentals Memory management tools Memory management tools –EMM386.EXE – This memory manager emulates expanded memory and makes upper memory available for use by the OS.

46. IT Essentials - Chapter 4 Operating System Fundamentals Memory management tools Memory management tools –HIMEM.SYS – Load this device driver to convert memory starting at 1MB available as XMS or extended memory. It is loaded from the config.sys file. –The syntax for this command is DEVICE=C:\DOS\HIMEM.SYS.

47. IT Essentials - Chapter 4 Operating System Fundamentals Memory management tools Memory management tools –DOS=HIGH – This option is added into the Config.sys file to tell the OS to move a portion of itself (such as MS-DOS Kernel) into the high memory area. It is usually combined with DOS=UMB to tell it to create an upper memory block using the syntax DOS=HIGH, UMB.

48. IT Essentials - Chapter 4 Operating System Fundamentals Memory management tools Memory management tools DEVICEHIGH/LOADHIGH – DEVICEHIGH/LOADHIGH – –DEVICEHIGH (used in Config.sys) and LOADHIGH (used in Autoexec.bat) both put upper memory blocks to use, once HIMEM.SYS and Emm386.exe have been loaded. To load a mouse driver high, for example, use this To load a mouse driver high, for example, use this syntax: DEVICEHIGH=C: \DOS\MOUSE.SYS

49. IT Essentials - Chapter 4 Operating System Fundamentals Other types of memory Other types of memory –Virtual Memory: Swap File in Windows 9x Swap File in Windows 9x Page File in Windows 2000 Page File in Windows 2000 –Hard disk drive space is manipulated to seem like RAM.

50. IT Essentials - Chapter 4 Operating System Fundamentals Other types of memory Other types of memory –RAM Drive Setting aside a portion of RAM to emulate a harddrive is a RAM drive. –For example, on a machine that has a hard drive partitioned into drives C and D, a RAM drive of 4 MB (4096 KB) can be created as E with the command: –DEVICE=C: \DOS\RAMDRIVE.SYS 4096

51. IT Essentials - Chapter 4 Operating System Fundamentals Memory conflicts Memory conflicts –General Protection Fault or GPF –Memory conflicts can be caused by two memory managers running at the same time. –This conflict results in the blue screen of death.

52. IT Essentials - Chapter 4 Operating System Fundamentals Real Mode Real mode memory addressing means that software, such as DOS or its applications, can address only 1,024 KB (1 MB) of RAM. In other words, real mode means that the microprocessor chip addresses the first 1,024 bytes of "conventional and upper memory" by actually assigning real addresses to real locations in memory. Real Mode Real mode memory addressing means that software, such as DOS or its applications, can address only 1,024 KB (1 MB) of RAM. In other words, real mode means that the microprocessor chip addresses the first 1,024 bytes of "conventional and upper memory" by actually assigning real addresses to real locations in memory.

53. IT Essentials - Chapter 4 Operating System Fundamentals Protected Mode Protected Mode –Protected mode allows one program to fail without bringing down the whole system.

54. IT Essentials - Chapter 4 Operating System Fundamentals Protected Mode Protected Mode –Protected mode allows one program to fail without bringing down the whole system. –The theory behind protected mode is that what happens in one area of memory has no effect on other programs.

55. IT Essentials - Chapter 4 Operating System Fundamentals Protected Mode Protected Mode –Protected mode allows one program to fail without bringing down the whole system. –The theory behind protected mode is that what happens in one area of memory has no effect on other programs. –When running in protected mode, a program is limited to its own memory space allocation, but it can access memory above 1MB.

56. IT Essentials - Chapter 4 Operating System Fundamentals Protected Mode Protected Mode –Protected mode allows one program to fail without bringing down the whole system. –The theory behind protected mode is that what happens in one area of memory has no effect on other programs. –When running in protected mode, a program is limited to its own memory space allocation, but it can access memory above 1MB. –Just about every operating system other than DOS runs in protected mode.

57. IT Essentials - Chapter 4 Operating System Fundamentals Before you take your online exam review the common DOS commands. Before you take your online exam review the common DOS commands.