Chapter 16, Operating System Fundamentals
|1|Chapter Overview
A.Operating System Basics
B.The Command Prompt and DOS Mode Operations
C.File Systems
Chapter 16, Lesson 1
Operating System Basics
|2|1.The Software Core
A.User interface
1.Makes use of a mouse, a keyboard, drop-down menus, and scrolling content to allow users to interact with the computer
2.The majority of Microsoft Windows–based programs use the same commands for functions such as adding and moving text and printing, opening, and saving files.
B.File system management
1.The OS is responsible for file management.
2.The design of the OS determines the naming convention for files.
C.Device management
1.Drivers and command sequences allow the OS to control computer components.
2.The OS provides methods for preparing storage media and working with file systems.
3.The OS controls the computer’s hardware and its functions and tracks hardware status.
D.Boot and installation routines
1.The OS includes boot sequence code.
2.OSs must be provided with installation routines and with troubleshooting and recovery techniques.
E.A well-designed OS includes error-handling capability.
F.A complete OS includes software for housekeeping chores that keep the system running optimally.
G.Modern OSs include networking support.
|3|2.A Short History of MS-DOS
A.The original IBM PC shipped with an OS called DOS in 1981.
1.DOS was the dominant OS until it was supplanted by Microsoft Windows 3.1 in 1992.
B.Many concepts and conventions used in Windows stem from DOS.
1.Some diagnostic routines require knowledge of the user command prompt.
a.Installing a new OS
b.Formatting a new hard drive
c.Repairing damage from viruses
C.Development and history of MS-DOS
1.Versions of MS-DOS began with 1.0 in 1981.
2.Version 7.0 in 1995 was the last version of MS-DOS as a stand-aloneOS.
|4|3.Understanding DOS
A.All versions of DOS were built for a specific class of CPU.
B.MS-DOS was never able to overcome critical limitations.
1.No native network support
2.Memory limitations
C.All versions used a command-line user interface.
D.Using the DOS prompt is a fundamental requirement in setting up a new system or hard disk drive.
|5|4.DOS Boot Sequence and Files
A.MS-DOS includes three core programs that are required for booting and loading the OS. These programs work in layers.
1.IO.SYS
a.Interface between the hardware and the OS code
b.Acts as the intermediary between hardware components and the software environment at the lowest layer
2.MSDOS.SYS provides key logic and basic commands at the middle layer.
3.COMMAND.COM is the interface between the user and the OS at the highest layer.
B.Two optional startup files provide support for custom commands, hardware devices, and applications.
1.CONFIG.SYS loads extra hardware and device drivers that are not built into IO.SYS.
2.AUTOEXEC.BAT loads programs, such as Terminate and Stay Resident programs (TSRs), and sets up environment variables.
|6|C.Summary of steps in booting the system
1.The power-on self test (POST) runs and invokes the OS.
2.The read-only memory basic input/output system (ROM BIOS) looks for an OS and checks for the presence of IO.SYS and MSDOS.SYS.
3.The OS processes CONFIG.SYS, if present.
4.COMMAND.COM is loaded.
5.The OS processes AUTOEXEC.BAT, if present.
6.If no other programs are invoked by AUTOEXEC.BAT, COMMAND.COM presents the active-drive prompt.
|7|D.The DOS file system
1.In MS-DOS, the file is the primary unit of data storage.
2.Files are organized into directories.
3.File and directory naming conventions
a.Can be up to eight characters long, followed by a period and a three-character extension
b.Universal file extensions used:
(1).exe: executable file
(2).com: command file
(3).sys: defines and configures options
(4).bat: executes a series of commands or launches programs
(5).txt: contains plain text
(6).doc: word processing file
(7).drv: configures a hardware device
c.Are not case-sensitive
|8|5.The Evolution of Microsoft Windows
A.Early versions of Windows used MS-DOS as a foundation and provided a graphical user interface (GUI) for MS-DOS.
1.Windows version 1.0 was released in 1985.
2.Windows 3.1 (1992) was the first version to become popular.
3.Windows 3.11 (1993) was the last 16-bit version and the most wellknown.
B.Microsoft Windows 95 was the first 32-bit version.
C.All applications designed for Windows have the same standard interface.
1.Basic commands for file, print, copy and save operations
2.Text and object selection methods
3.Clicking and dragging mouse functions
4.Scroll bars for displaying text and graphics
5.Resizing and positioning of windows
6.Cutting and pasting functions among applications
D.Multitasking allows users to have more than one application open.
|9|E.Operating modes
1.Real mode
a.Original purpose of Windows was to act as a GUI.
b.Did not include memory management or multitasking
c.Could use only 1 MB of random access memory (RAM)
d.Is virtually obsolete
2.Standard mode
a.Starting Windows in standard mode allowed programs to run in protected mode, in which they
(1)Could address up to 16 MB of RAM
(2)Did not share areas of memory
(3)A General Protection Fault (GPR) indicated that a program was trying to write data outside its allocated area in memory.
b.Standard mode allowed Windows to manage resources for applications.
3.386 enhanced mode
a.Introduced with the 386 processor
b.Allowed addressing up to 4 GB of RAM
c.Supported virtual memory
d.Allowed multiple MS-DOS programs to run simultaneously
4.Certain applications could be purchased with a runtime version of Windows, allowing the application to run even if the computer did not have Windows installed.
|10|6.Windows Resource Management
A.Device drivers are files that establish communication between a device and the OS. All resources are presented to Windows through device drivers.
B.Applications request access to resources by using an application programming interface (API).
C.A dynamic-link library (DLL) file can address the Windows core directly.
1.Some programs overwrite standard DLLs.
D.Programs request resources through the KRNL386.EXE file, which allocates an area of RAM called a segment.
|11|E.Virtual memory (the ability to make something other than RAM chips hold data) uses a swap file on the hard disk to store code.
1.The swap file acts as a virtual RAM chip.
F.To run multiple DOS programs, Windows creates virtual 8086 machines (VMs).
1.Windows uses a segment of RAM to present an 8086 machine environment to the DOS program.
2.Windows runs itself in one VM and allocates another VM to an MS-DOS program.
3.DOS programs run individually in separate VMs.
|12|7.Windows Operating Systems
A.Microsoft Windows for Workgroups 3.11 is an upgrade to Windows 3.1.
B.Windows 95, Windows 98, and Microsoft Windows Me
1.Windows 95 ushered in the era of Plug and Play.
2.These versions can easily be networked.
3.Make use of the Internet
4.Are aimed at home and general office markets
C.Microsoft Windows NT
1.Released in 1993 and aimed at scientific, engineering, and design markets
2.Microsoft Windows NT Workstation is aimed at the advanced user.
3.Microsoft Windows NT Server is designed for robust networking.
4.Both provide high security not available in earlier Windows operating systems.
5.Service packs are available to provide fixes to the current version.
6.Three levels of OSs:
a.Workstation (Professional in Microsoft Windows 2000) allows professional users to share resources.
b.Server is a complete local area network (LAN) host with user management features.
c.Advanced Server includes advanced tools for complex network environments.
D.Windows 2000 is the replacement for Windows NT.
1.Supports Plug and Play
2.Offers better multimedia tools
3.Has more advanced Internet features and networking tools
4.Three versions:
a.Professional (replaces Workstation)
b.Server
c.Advanced Server
E.When upgrading from Windows 95, Windows 98, or Windows Me to Windows NT or Windows 2000, be aware that not all hardware and applications are compatible.
Chapter 16, Lesson 2
The Command Prompt and DOS Mode Operations
|13|1.The COMMAND Command
A.MS-DOS uses a text-based command-line user interface to interact with the OS.
1.The user must memorize and type commands.
2.The latest versions of Windows incorporate a limited version of DOS.
B.Advantages to the simpler text-based interface
1.Requires no drivers—the display functions are built in to the system hardware
2.Eliminates the need for 32-bit drivers and high memory management, making it an excellent troubleshooting tool
3.The command line can be used to recover data and repair Windows when it fails.
C.The COMMAND.COM file provides the user interface.
1.Typing a command and pressing Enter executes the command.
2.Commands are not case-sensitive.
3.You can personalize the appearance of and information presented by the command prompt.
|14|D.Working with the prompt
1.At the prompt, you can get help by typing PROMPT /? or HELP PROMPT and pressing Enter.
2.DOS HELP returns information on how to customize the prompt and the information that appears.
|15|E.Internal and external commands
1.External commands are programs that exist as separate files.
a.Can be used only when you are in the directory where the file exists, or when you specify the program’s pathname
2.Windows has its own set of system utilities.
3.Internal commands are management tools contained within the COMMAND.COM file. They can be used at the prompt.
4.Command mode in DOS requires that you type a command, whereas in Windows you can click an icon to launch a program.
|16|2.DOS Mode Navigation and File Management
A.The DOS file system uses a tree structure.
1.The primary volume on a drive is called the root and can contain both files and directories.
a.A directory is a collection of files.
b.Each directory creates another branch, which can contain other directories or files.
2.A directory within a directory is called a subdirectory.
3.The root directory has no name and is represented by a backslash (\).
B.A fully qualified path is the entire list of directories from the root to thefile.
C.The DIR command displays one of the following:
1.The contents of the current directory (when the DIR command is used alone)
2.A specified directory (when the DIR command uses a specific path)
D.DOS does not support Windows long filenames.
E.The MD (make directory) command creates a new directory.
|17|3.The PATH Command
A.The PATH command allows you to
1.Display or set a search path for executable files
2.Change the directories that DOS will search and specify an order for the search
B.Type PATH and press Enter to display the current path.
C.Use %PATH% to append the old path to the new path.
D.Any program in the directories listed in the path can be executed from any location on the computer.
|18|4.Creating a Batch File
A.A batch file is an executable file that runs a series of existing commands or applications.
B.When you enter the name of the batch file at a prompt, the commands are executed in sequence.
C.Any executable that can be entered at the prompt can be included in a batch file.
|19|5.Renaming a File
A.The RENAME or REN command allows you to rename a file.
B.The CD command allows you to change directories.
1.When followed by two dots (CD..), the command changes the prompt to the parent directory of the current directory.
2.When followed by a backslash (CD\), the command changes the prompt to the root of the current drive.
C.The CLS command clears the screen.
|20|6.Using Edit
A.Edit is the MS-DOS text editor.
1.Is a full-screen text editor that includes pull-down menus with options for editing, saving, creating, and printing ASCII files
2.Includes extensive online help
B.If the file you want to edit is not in the path, you need to enter the complete directory path to the file.
C.Unless you have a mouse driver for DOS in AUTOEXEC.BAT, you will not have mouse support in Edit.
|21|7.Summary of DOS Terminology
A.Directory: a location for storing files
B.DOS prompt: displays the active drive letter and directory
C.Path: the address to a file
D.Prompt: the user interface provided by COMMAND.COM
E.Syntax: the correct format in which to type a command
F.Wildcards: the asterisk (*) and question mark (?), which can be used with the DIR command to expand a search by looking for files with similar names or extensions
|22|8.CONFIG.SYS Commands
A.The CONFIG.SYS file runs first.
B.CONFIG.SYS sets up and configures the computer’s user-defined hardware components.
C.Not all settings are available (or recommended) in all versions of Windows.
|23|9.AUTOEXEC.BAT Commands
A.The AUTOEXEC.BAT file executes commands and loads TSRs.
B.TSRs can cause conflicts and problems that are difficult to isolate.
C.The REM command can be used to place comments that tell the system to ignore command lines.
1.The REM command is useful for troubleshooting the AUTOEXEC.BAT and CONFIG.SYS files.
Chapter 16, Lesson 3
File Systems
|24|1.File System Basics
A.The file system acts as an interface with hardware storage devices, organizing data in a form that the system and applications can use.
B.Different types of storage media require different types of formatting or translation.
C.The file system defines file naming conventions, file size, and, in some cases, the capacities of CD-ROMs, DVDs, and Zip drives.
D.Magnetic media employ several different file systems, depending on theOS.
|25|E.Key terms that are necessary to understand the operation of file systems:
1.Block
2.Boot disk
3.Boot sector
4.Cluster
5.Dual boot
6.Encryption
7.End-of-file (EOF) marker
8.File
9.FAT
10.File format
11.File handle
12.File locking
13.Filename
14.Folder
15.Format
16.Low-level format
17.Master boot record
18.Partition table
19.Primary partition
20.Sector
21.Track
22.Volume
|26|2.Comparing and Choosing File Systems
A.The choice of a file system depends on several factors.
1.Will the system be dual boot?
2.How many hard disk drives will the system have?
3.What size will the hard disk drives be?
4.How large will the partitions be?
5.Are legacy applications in use?
6.Are advanced file system features needed?
7.Is security on resources required?
|27|3.FAT-Based File Systems
A.All modern PCs can use FAT-based file systems.
B.Organizes files by listing them in a table
C.Two copies of the FAT table are maintained in the root directory of the primary partition.
D.FAT was originally developed for and is still used for floppy disks.
E.Three basic versions of FAT (the number designates the number of bits used in the entry in the table):
1.FAT12 was used by floppy disk drives.
2.FAT16 was introduced with MS-DOS 3.0 to support larger hard disk drives.
3.FAT32 is the preferred file system for Windows 95 and later versions.
a.It supports long filenames.
|28|F.FAT16 and FAT32 compared and contrasted
1.In the days of MS-DOS, FAT16 was the only file system available.
2.FAT32 offers several enhancements over FAT16 but lacks some of its compatibility.
|29|4.The NT File System (NTFS)
A.Introduced with Windows NT
B.Supports long filenames and is optimized for multiuser environments
C.Provides file and folder level security
D.Is more reliable than previous file systems
E.Windows NT does not support all features of NTFS 2000.
|30|F.Advantages and disadvantages of NTFS
1.Advantages of NTFS:
a.Supports volumes up to 2 terabytes (TB) in size
b.Maintains a log that can be used to recover a volume
c.The root folder can hold an unlimited number of files.
d.Faster file access due to B-tree file structure
e.Allows compression of files and folders
f.Allows access control (security) to be set on resources for an individual user or for a group of users
g.Can limit space usage with disk quotas for individual users
2.Disadvantages of NTFS:
a.NTFS volumes cannot be accessed under MS-DOS, Windows 95, or Windows 98.
b.NTFS volumes cannot be used as a primary partition for dual booting with MS-DOS, Windows 95, or Windows 98.
c.For volumes smaller than 400 MB, performance could decrease.
|31|5.File System Size Limitations
A.Different OSs handle file system cluster size differently.
B.Under FAT volumes, drives smaller than 16 MB are formatted as FAT12.
C.MS-DOS, Windows 95, and Windows 98 cannot access FAT16 volumes larger than 2 GB.
|32|6.File System Security
A.FAT attributes on FAT file systems
1.FAT offers attributes to protect files from being overwritten or viewed.
2.File attributes can be set by
a.Using the ATTRIB DOS-mode command
b.Right-clicking a file in Windows and selecting the Properties option
B.NTFS file and folder security
1.Uses the concept of permission to control access to files and folders
2.Permissions are set using the Security tab of the file or folder.
3.Permissions are assigned to specific user or group accounts.
4.Basic permissions are Full Control, Modify, Read & Execute, Read, and Write. Advanced permissions offer more complex control.
|33|Chapter Summary
A.An OS is the interface between the hardware and the user.
B.All OSs have basic features dealing with user interface, memory, and file management.
C.Technicians need to know how to perform command prompt operations.
D.Understanding MS-DOS and the DOS startup files is important for a technician working with older OSs.
E.Internal and external commands can be used to configure and troubleshoot the system.
F.The oldest and most basic file system is FAT16.
G.FAT32 offers enhanced features such as support for long filenames and larger hard disks.
H.NTFS supports file and folder security, compression, and disk quotas.
Outline, Chapter 161
ALS: A+ Certification, Third Edition