Understanding Windows

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Understanding Windows

• Chapter 12

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Overview

• In this chapter, you will learn to
• Identify and explain the basic functions of an
  operating system
• Identify the features and characteristics common
  to all Windows PCs
• Identify and differentiate the features an
  characteristics of Windows 9x/Me
• Identify and differentiate the features an
  characteristics of Windows NT/2000/XP

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Functions of the Operating System
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Functions of an Operating System

• Communicate with hardware
• Provide a user interface
• Provide a structure for access to applications
• Enable users to manipulate programs and data

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Operating System Traits

• An OS works only with a particular type of
  processor
• An OS begins running as soon as the PC finishes
  its POST
• Application programs cannot run on a PC without
  an OS
• The OS provides a set of application programming
  interfaces (APIs)
• An OS must be able to use new software and
  hardware

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Communicating with Hardware

• The system BIOS is programming code that tells
  the computer how to talk to basic hardware
• The OS works with the BIOS to talk to these
  devices
• When the BIOS does not know how to talk to a
  piece of hardware, the OS talks directly to the
  device
• Most OSs use device drivers provided by the
  manufacturer (Bring Your Own BIOS) to interpret
  the language necessary to talk to a new device
• When theres a problem, the OS should provide
  error handling or at least error notification

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Creating a User Interface

• A user interface needs to
• Show what applications are available
• Provide an easy way to access those applications
• Provide a way to label and save the data
  generated using the application
• When a program starts, the user interface must
  disappear and allow the application to take over
  the screen
• While the application is running, the OS must
  provide access to hardware as needed
• When the application is shut down, the OS must
  return the user to the user interface

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Organizing Programs and Data

• The OS must be able to organize programs and data
• What is data and how can we distinguish between
  different types of data?
• What are programs and what type of program is it?
• How can I distinguish the various places to store
  the data or programs?
• How can I efficiently retrieve the data or
  program?

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Operating System Implementations

• Command Line
• Character-based or text-based
• Disk Operating System (DOS)
• Single-tasking
• DOS consists of
• IO.SYS
• MSDOS.SYS
• COMMAND.COM
• DOS configuration files
• CONFIG.SYS
• AUTOEXEC.BAT

• Graphical User Interface (GUI)
• Not necessarily the OS
• Win95, Win98, Win31 ran on top of DOS
• Apples OS 9 and OS X operate only as a GUI
• WinNT, Win2K, WinXP are GUI operating systems
  with a command line built in

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Common Windows Features and Characteristics
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User Interface

• Login
• Every version of Windows supports multiple users
• Requiring a user login increases security
• Desktop
• Primary interface to the computer
• Taskbar and Start Menu
• Runs along the bottom of the desktop and includes
  up to four sections
• Start menu allows access the installed programs
• System tray shows programs running in the
  background
• Quick Launch enables you to launch often-used
  programs with a single click

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User Interface

• My Computer
• Provides access to drives, folders, and files
• Customizable may display different views, show
  hidden files, hide file extensions, and more
• Windows Explorer
• Another utility for accessing drives, folders,
  and files
• My Documents
• My Pictures, My Music, My Videos

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User Interface

• Recycle Bin
• When you delete files they are sent to the
  Recycle Bin, a special folder just in case you
  change your mind
• Network Neighborhood or My Network Places
• Shows the current network connections available
  to you

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Tech Utilities Control Panel

• Maintenance, upgrade, and configuration aspects
  of Windows
• Start?Settings?Control Panel
• Contains programs, called applets
• Any icon in the Control Panel is a file with a
  CPL extension
• If Control Panel wont start, one of these is
  probably corrupt rename each one until you find
  the bad one
• Each applet displays text that helps to explain
  its functions

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Tech Utilities Control Panel
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Tech Utilities Device Manager

• Device Manager is a primary tool for dealing with
  devices and device drivers in Windows
• A red x or a yellow exclamation
  point is displayed, if Windows
  detects a problem
• Devices are organized in
  special groups called types
• Access thru the System applet in
  Control Panel

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Tech Utilities System Tools

• System Tools is a collection of tech utilities
  found on the Start menu
• Start ? Programs ? Accessories ? System Tools

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Tech Utilities Command Line

• Command Line
• Start ? Run ? command
• Windows 2000/XP offer you a more powerful command
  line Start ? Run ? cmd

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Tech Utilities MMC

• Microsoft Management Console (MMC)
• A shell program that holds individual utilities
  called snap-ins
• Start ? Run ? mmc
• You start with a blank console and then add
  snap-ins then save the new customized console
  you created
• File ? Add/Remove Snap-ins ? Add

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Tech Utilities Adminstrative Tools

• Administrative Tools
• A folder that holds many pre-defined MMC consoles
  built by Microsoft
• Go to Control Panel and click on Administrative
  Tools
• The three most used Administrative Tools are
• Computer Management
• Event Viewer
• Performance

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Tech Utilities Computer Management

• Computer Management
• A pre-defined MMC that pulls together snap-ins
  related to many computer management options

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Tech Utilities Event Viewer

• Event Viewer
• Keeps track of events that happen with your
  computer

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Tech Utilities Performance

• Performance
• System Monitor may show real time data
• Performance Logs and Alerts

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Services

• Services
• Separate programs that handle a lot of functions
  for Windows
• Found in Administrative Tools
• Double-click on any service to examine its
  properties and settings
• Services start automatically, manually, or may be
  disabled

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System Folder

• System Folder
• Folder where the OS files were installed
• systemroot
• windir for Win9x

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What is the Registry?

• Registry
• A unified database where Windows stores all
  hardware and software configuration information
  for the local computer
• Hardware, central processor, keyboard, mouse,
  etc.
• Device drivers
• Applications
• Network protocols
• NIC settings
• User account information like group membership,
  rights and permissions

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Registry Editors

• Regedit
• Clearly better in key searching down to the value
  of the keys
• Used by Windows 9x/Me
• Also installed in Windows NT/2000/XP
• Regedt32
• Used by Windows NT/2000/XP Better for adding keys
  and modifying their values
• Searches only down to keys and subkeys not
  values
• When using the Registry Editors, be very careful!
• Does not recognize syntax or semantic errors
• May prevent your operating system from loading

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REGEDIT
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REGEDT32
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Registry

• The Registry has six main groups , or root keys
  shown below

HKEY_DYN_DATA is used in Windows 9x not 2000 or
XP
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HKEY_LOCAL_MACHINE

• Configuration data about local computer
• Used by applications, device drivers and Windows
• Determines which device drivers and services load
  during startup
• Same regardless of user

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HKEY_USERS

• Stores all the personalization information for
  all users on the PC
• Subkeys are
• DEFAULT subkey
• System default profile used when CtrlAltDel
  logon screen is displayed
• Security identifier (SID) of user currently
  logged on the computer

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HKEY_CURRENT_USER

• Data about user currently logged on interactively
• Copy stored for each user account that has ever
  logged on to the computer in systemroot\Profiles\u
  ser_name in Ntuser.dat
• Points to same data as under HKEY_USERS\SID_of_the
  _currently_logged_on_ user
• Takes precedence over duplicate settings in
  HKEY_LOCAL_MACHINE

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HKEY_CLASSES_ROOT

• Information about file associations and data
  associated with COM objects (Component Object
  Model OLE)
• Points to CLASSES subkey under HKEY_LOCAL_MACHINE\
  SOFTWARE

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HKEY_CURRENT_CONFIG

• Data about active hardware profile
• Extracted from SOFTWARE and SYSTEM keys of
  HKEY_LOCAL_MACHINE

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Virtual Memory

• All versions of Windows use virtual memory
• Windows swap files are used to implement virtual
  memory
• Windows sets the initial size of the swap file
  automatically according to the free space
  available on the C drive
• The swap file in Windows 9x is called WIN386.SWP
  it is known as PAGEFILE.SYS in Windows 2000

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Virtual Memory

• When you need to run another program but your RAM
  is filled up, Windows will offload something that
  hasnt been used recently from RAM to the hard
  drive into a swap file to make room
• If you need to access the data that was offloaded
  into RAM, Windows will retrieve it from the hard
  drive

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Essential Windows

• You should already have basic user skills in
  Windows. As a review check out Essential Windows
  on line at www.totalsem.com

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Features and Characteristics of Windows 9x/Me
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Windows

• Windows 3.1 was a graphical shell that ran on top
  of DOS
• Microsoft debuted Windows 95 as its first
  standalone GUI operating system
• Windows 9x and Me followed in later years
• Many files and configuration utilities were held
  over from earlier OSs

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The Windows Boot Process

• Windows 9x is a combination of the DOS
  protected-mode interface (DPMI) and a
  protected-mode GUI
• Windows 9x first starts the DOS aspect of Windows
  and then the GUI
• Booting Windows 9x without the GUI from the boot
  menu is different than running a DOS window
  inside Windows 9x

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FAT32

• Later versions of Windows 95 and all versions of
  Windows that followed support the FAT32 file
  format
• Partitions up to 2 terabytes in size

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Long Filenames

• Windows 9x/Me
• Allows long file names up to 255 characters in
  length
• Removed the old 8.3 filename limitation of DOS
• Adopted the 16-bit unicode character set
• Unicode supports 65,536 characters
• ASCII used by DOS was 8-bits and supported only
  256 characters

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DPMI Core Files

• IO.SYS
• Combined the previous IO.SYS and MSDOS.SYS into
  IO.SYS
• MSDOS.SYS
• Used as a startup options file read-only,
  hidden text file in root directory
• COMMAND.COM
• Not needed if the system will always run in the
  GUI mode

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Boot Menu
Press F8 (or the left Ctrl key in Windows 98)
when Starting Windows.. appears to access the
Boot Menu
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Boot Menu

• Normal
• Logged
• Creates a bootlog.txt file detailing the boot up
  process
• Safe mode
• Only the OS, mouse, keyboard, and VGA video
  drivers are loaded
• Useful when Windows wont boot due to a bad
  driver
• Safe mode with network support
• Step-by-step confirmation

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Boot Menu

• Command prompt only
• Does everything but start the GUI
• Just type win to start Windows
• Safe mode command prompt only
• Skips all startup files
• Must reboot to start Windows
• Previous version of MS-DOS
• Useful only if you installed Windows over a true
  DOS system

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MSDOS.SYS

• MSDOS.SYS
• Hidden, read-only text file that replaces many of
  the CONFIG.SYS and AUTOEXEC.BAT functions
• Edit using any text editor (after unchecking its
  attributes)
• Organized like an INI file with groups and
  options under each setting
• There are many useful options in the Options
  group see pages 429-430 in the book for a
  listing

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Configuration Files

• Windows 9x/Me will use CONFIG.SYS and
  AUTOEXEC.BAT to load legacy device drivers and
  terminate and stay resident (TSR) programs

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Legacy GUI Files

• After the DPMI-level OS files, configuration
  files, and utilities load, WIN.COM runs and
  initiates the graphical portion of the OS
• Incorporates legacy INI files to provide support
  to older applications
• INI files are text files that may be edited with
  any text editor such as Notepad
• INI files are broken in sections called groups
• Two main INI files from Windows 3.1 that
  still exist in later versions of
  Windows are SYSTEM.INI and WIN.INI

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SYSTEM.INI

• All resources were initialized in the SYSTEM.INI
  file in Windows 3.1
• SYSTEM.INI still exists in Windows 2000/XP today
  to provide backward compatibility
• Windows 9x/Me require SYSTEM.INI

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WIN.INI

• WIN.INI provided the personalizations of Windows
  3.1
• Rarely have a WIN.INI in Windows 9x/Me/2000/XP
• Dealing with SYSTEM.INI and WIN.INI is usually
  not necessary
• Unless you get error messages indicating a device
  driver cant be found
• Just find the culprit and put a semicolon in
  front of the line to disable it
• There are two lines in WIN.INI that may cause
  problems
• LOAD and RUN that automatically loads programs
  when Windows starts

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The Windows 9x GUI Architecture
User interface
Core functions handled by the Kernel, Graphical
Device Interface, and User modules
Virtual Memory Manager Installable File System
Real-mode drivers are loaded by config.sys or
autoexec.bat. Protected mode drivers are loaded
with the GUI
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Major Difference Among Windows

• Windows 98 is basically Windows 95 with a lot of
  new toys to improve usability or to address bugs
• A startup disk is a special bootable floppy disk
  that contains utilities to help you fix a system
  that wont boot Windows
• Both 95 and 98 allow you to make a startup disk
• 95s does not support a CD-ROM
• 98s supports almost all CD-ROMs

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Major Difference Among Windows

• FAT32 is supported in all Windows versions except
  the first version of Windows 95
• System Information Tool
• Provides a launch point for almost every Windows
  98/SE/Me utility
• Windows Update
• Utility to keep Windows up to date
• Found on the Start menu

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Major Difference Among Windows

• Disk Cleanup Utility
• Active Desktop
• Load active web pages on your desktop
• Vastly improved version of Internet Explorer

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Major Difference Among Windows

• Internet Connection Sharing
• Included since Windows 98 SE
• Enables multiple PCs to share an Internet
  connection
• System Restore
• Windows Me shares the core files and structure of
  Windows 9x but has the look and feel of Windows
  2000
• Enables you to create Restore Points that will
  take your system back to its previous state at a
  given point in time

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But Underneath

• Windows 98, 98 SE, and Me are nearly identical to
  Windows 95

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Features and Characteristics of Windows NT/2000/XP
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Windows NT

• Microsoft released Windows NT in 1996
• High-performance 32-bit GUI OS
• Windows 2000 and XP share the same core
  structure, files, and features but differ in ease
  of use and hardware support
• Windows NT looks like Windows 95 but thats where
  the similarities end

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OS Organization

• Robust, scalable, cross-platform
• Object-oriented approach designed to support
  multiple platforms such as x86, DEC Alpha, MIPS,
  and PowerPC by using a Hardware Abstraction Layer
• Robustness comes from separating process and
  running them in various subsystems
• Supports symmetric multiprocessing (SMP) allowing
  support for up to 32 CPUs

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Window NT Organization
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NT File System (NTFS)

• NT File System (NTFS)
• Robust and powerful
• Long filenames containing up to 255 characters
• Advanced FAT called the Master File Table (MFT)
• Keeps a backup copy in the middle of the drive
  which shows up as a small, immovable chunk of
  data when you defrag
• Backwards compatible with DOS and Windows 9x
• Transaction logging determines incomplete file
  transactions, and restores the file back to the
  original format automatically and invisibly

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NTFS Security

• To gain access to a Windows NT/2000/XP system,
  you must have a valid user account and password
• Every Windows NT/2000 PC has an administrator
  account that has full access to everything
• Create users using Users and Passwords in Windows
  2000 or User Accounts in Windows XP

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Groups

• A group is a collection of user accounts that
  share the same access capabilities
• Assign access to a group and then put users into
  the group
• Users will inherit the access assigned to the
  group
• Windows provides several built-in groups

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Built-in Groups

• Administrators
• May perform all administrative tasks on the
  computer
• Backup Operators
• May use Windows Backup
• Guests
• May perform only specific tasks that are granted
• Guest account is a member

• Power Users
• May create and modify local user accounts and
  share resources on the local computer
• Replicator
• Supports file replication in a domain
• Users
• May perform only tasks specifically assigned
• Local user accounts that are created become
  members
• Everyone

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NTFS Permissions

• NTFS permissions in NT/2000/XP
• Details every user and group that has access to a
  file or folder
• Lists the specific level of access allowed
• Available only on volumes formatted as NTFS
• NTFS security is effective whether a user
• Gains access at the computer
• Gains access over the network

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NTFS Permissions

• Ownership
• When you create a new file or folder you become
  the owner
• Owners have full control
• Be default, everyone is given full control
  permission
• Take Ownership
• Enables a user permission to take ownership of a
  file or folder
• Administrator account can take ownership without
  being given permission

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NTFS Permissions

• Change permission
• Can give or take away permissions for other
  accounts
• Folder permissions
• Apply to folders
• File permissions
• Apply to files

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NTFS Folder Permissions

• Full Control
• Enables you to do anything you want
• To deny all access, deny Full Control
• Modify
• Cannot delete files or subfolders but may modify
  them
• Read Execute
• Enables you to see the contents of the folder and
  subfolders
• List Folder Contents
• Enables you to see the contents of the folder and
  subfolders

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NTFS Folder Permissions

• Read
• Enables you to read any files in the folder
• Write
• Enables you to write to files and create new
  files and folders
• By default, permissions are inherited from parent
  folders
• This may be prevented by removing the check mark
  at the bottom

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NTFS Folder Permissions
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NTFS File Permissions

• Full Control
• Enables you to do anything
• Modify
• Enables you to do anything except take ownership
  or change permissions
• Read Execute
• If the file is a program, you can run it
• Read
• If the file is data, you can read it
• Write
• Enables you to write to the file

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Combining Permissions

• Users effective permissions are the cumulative
  (or least restrictive) permissions resulting from
  a combination of user and group permissions

• Deny permission overrides all other
  permissionsDeny always becomes the effective
  permission
• File permissions override folder permissions

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Booting Up vs. Going Graphical

• Windows 9x and Windows 2000 differ significantly
  in the level of integration between the graphical
  interface and the text-based functions
• Both operating systems have primary boot files
  that start the operating system
• The boot file must be on the boot partition and
  the GUI file can be installed in any other drive
  letter
• Microsoft terminology for NT/2000
• System partition partition you boot from
• Boot partition partition that holds NT or 2000
  files

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Booting Up vs. Going Graphical

• Windows NT and Windows 2000 do not have a pure
  command prompt environment
• Windows NT can log on to the command prompt only
  after the GUI is started

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Preboot Sequence

• The computer runs power-on self test (POST)
  routines to determine the amount of physical
  memory, hardware components, and so on
• The computer BIOS locates the boot device and
  loads and runs the master boot record (MBR)
• The MBR locates, loads into memory, and executes
  the boot sector
• The computer loads and initializes the NTLDR file

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The Boot Process

• NT Loader manages the booting process
• Windows NT/2000/XP boot files that must be in the
  root directory of the system partition are
• NTLDR (NT Loader)
• BOOT.INI
• NTDETECT.COM
• NTBOOTDD.SYS (only needed for SCSI controllers
  that dont have their own ROM BIOS)
• After the boot files start the PC, NTLDR passes
  control to the Windows NT kernel (NTOSKRNL.EXE)
• The GUI begins to load

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Boot Files NTLDR

• NTLDR (NT Loader) manages the boot up process
  until control is handed over to NTOSKRL (NT
  kernel)
• To find available operating systems, NTLDR reads
  the boot.ini file
• If multiple OSs are available a menu shows up

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Boot Files BOOT.INI

• BOOT.INI is a text file that lists the available
  OSs and where to find the boot partition

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More Boot Files

• BOOTSEC.DOS is read by NTLDR if it finds a
  different OS to load
• NTDETECT.COM detects the hardware if you choose
  to boot to NT/2000/XP
• NTBOOTDD.SYS is used if NTLDR detects that the
  boot partition resides on a SCSI drive that lacks
  a ROM chip for BIOS support

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Service Packs

• Windows NT uses service packs to fix operating
  system bugs and limitations in the architecture

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Major Differences among Windows NT, 2000, and XP

• Windows 2000 combines an improved NT core with
  the ease-of-use and tech-friendly elements from
  Windows 9x
• The robustness of NT with the Windows 98 user
  interface
• Windows XP extended that merger into a fully new
  OS
• User organization is better to enhance file and
  folder security
• NTFS 5.0 added encryption, mount points, disk
  quotas, and dynamic disks to NTs NTFS 4.0

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Major Differences among Windows NT, 2000, and XP

• Easier administration through Microsoft
  Management Console and the Computer Management
  tool
• Windows XP improved upon 2000 by adding built in
  support for burning CDs, an improved Start menu,
  and the Windows Update utility
• Windows XP has the Files and Settings Transfer
  Wizard that allows you to transfer everything
  from an old drive to a new one (get the update
  before using)

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Major Differences among Windows NT, 2000, and XP

• Windows XP comes with System Restore to take a
  snapshot of your system in order to restore it to
  its previous state
• Driver Rollback enables you to rollback
  individual device drivers in Windows XP
• Remote Assistance is possible with Remote Access
• Gives you the ability to take control of any
  Windows XP PC remotely

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