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Operating Systems Operating Systems and File Managementand File Management
Chapter 4Chapter 4
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4 Chapter Contents
Section A: Operating System Basics Section B: Today’s Operating Systems Section C: File Basics Section D: File Management Section E: Backup Security
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4SECTION A
Operating System BasicsOperating System Basics Operating System Activities User Interfaces The Boot Process
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4SECTION A
Operating System BasicsOperating System BasicsAt the most basic level, what is an operating system?1. An integrated circuit within the CPU2. A start-up program stored in ROM3. A special purpose piece of hardware that
controls the operation of your computer4. A large and complex computer program that
manages and controls the operation of your computer’s resources.
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4 Operating System Activities
An operating system is the system softwaresystem software that acts as the master controller for all activities that take place within a computer system
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4 Operating System Activities
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4 Operating System Activities
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4 Operating System Activities
MultitaskingMultitasking provides process and memory management services that allow two or more tasks, jobs, or programs to run simultaneously
Within a single program, multithreadingmultithreading allows multiple parts, or threads, to run simultaneously
An operating system’s multiprocessingmultiprocessing capability supports a division of labor among all the processing units
Modern operating systems control many things at once:
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4 Operating System Activities
Operating System Categories– Single-user operating system– Multiuser operating system– Network operating system– Desktop operating system
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4 User Interfaces
The combination of hardware and software that helps people and computers communicate with each other
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4 User Interfaces
Menus, submenus, and dialog boxes
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4 The Boot Process
During the boot process, the operating system kernelkernel is loaded into RAM– The kernel provides essential operating system
services
Your computer’s small bootstrap programbootstrap program is built into special ROM circuitry housed in the computer’s system unit
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4 The Boot Process
From hereFrom here to hereto here
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4SECTION B
Today’s Operating SystemsToday’s Operating Systems Microsoft Windows Mac OS UNIX and Linux DOS Handheld Operating Systems
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4 Microsoft Windows
WindowsXP
WindowsVista
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4 Mac OS
You can tell when you’re usingMac OS by the Apple logo thatappears on the menu bar. TheMac OS X interface includes allthe standard elements of a GUI,including icons, menus, windows, and taskbars.
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4 Mac OS
Dual Boot:On a Macintosh computer with Boot Camp, you can boot into Mac OS X or into Windows XP.
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4 Mac OS
Mac OS X on an Intel Mac offers the ability to run Windows and Windows application software in addition to software designed for the Macintosh– Dual boot
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4 UNIX and Linux
Several Web sites offer a Linux distributionLinux distribution, which is a package that contains the Linux kernel, system utilities, applications, and an installation routine
Trivia: The name Linux is derived from “Linus” (after it’s creator, Linus Torvald) and “Minix” (a compact version of the Unix operating system).
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4 Why is Linux so popular? It is based on the proven UnixUnix operating system
– Multi-tasking, multi-threading, multi-processor technology first developed in the late 1970’s
– Created as a platformplatform for networking and software development
– File systemFile system protection, security
The source code is “OpenOpen,” so systems programmers can download it, modify it and create their own OS versions/features
Free! Free! Or, at least, cheap cheap (relatively)
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4 UNIX and Linux
Linux users can choose fromseveral graphical interfaces.Pictured here is the popularKDE graphical desktop.
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4 DOS Disk Operating System First operating system that many used Command line interface (i.e., not not a GUI)
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4 Handheld Operating Systems
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4 Quick Quiz1. The _____ provides essential operating system services,
such as memory management and file access.2. True/False: A GUI provides a way to point and click a
mouse to select menu options and manipulate graphical objects that are displayed on the screen.
3. ____________ provides process and memory management services that allow two or more tasks, jobs, or programs to run simultaneously.
a. Multitaskingb. Multithreadingc. Networkingd. Multiprocessing
kernel
Multitasking
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4SECTION C
File BasicsFile Basics File Names and Extensions File Directories and Folders File Formats
What is a “file?”What is a “file?”
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4 Computer Files A named collection of data that exists in
computer storage.– Documents– Database records– Pictures, Music, etc.
File Attributes– Name– Format– Location– Size, Date, etc.
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4 File Names and Extensions You must adhere to file-naming conventionsfile-naming conventions
when saving files– Maximum length (255 in Win)– Prohibited characters– No reserved wordsreserved words– Case sensitivity
File extensions are usually related to the file formatfile format– Native file formatNative file format for applications
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4 File Directories and Folders
An operating system maintains a directorydirectory for each disk, tape, CD, DVD, or USB flash drive– Root Root directory– Subdirectory
• Depicted as folders
A computer’s file locationfile location is defined by a file specification, or pathpath
C:\My Music\Reggae\Marley One Love.mp3
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4 File Formats
Windows uses a file associationfile association list to link a file extension to its corresponding application software
Although a file extensionfile extension is a good indicator of a file’s format, it does not really define the does not really define the formatformat– A file headerheader is a section of data at the beginning
of a file that contains information about a file
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4 File Formats
A software application can open files that exist in its native file format, plus several additional file formats
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4 File Formats
An easy way to convert a filefrom one format to another isto open it with an applicationthat supports both file formats,and then use the Save AsSave As dialogbox to select an alternativefile format.
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4SECTION D
File ManagementFile Management Application-based File Management File Management Utilities File Management Metaphors Windows Explorer File Management Tips Physical File Storage
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4 Application-based File Management
Applications typically provide a way to open files and save them in a specific folder on a storage device
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4 Application-based File Management
The Save As dialog boxnot only helps you namea file and designate itsdestination drive, butalso allows you torename files, delete files, create folders, andrename folders.
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4 File Management Utilities File management
utilitiesutilities show you the files stored on your disks and help you work with them
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4 File Management Metaphors
Storage metaphors help you visualize and mentally organize the files on your disks– Logical storage models
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4 Windows Explorer
Windows Explorer makes it easy to drill down through the levels of the directory hierarchy to locate a folder or file.
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4 Windows Explorer
Windows Explorer allows you to manipulate files and folders in the following ways:– Rename– Copy– Move– Delete
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4 File Management Tips
Use descriptive names Maintain file extensions Group similar files Organize your folders from the top down Consider using the My Documents default
directory Do not mix data files and program files
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4 Physical File Storage
The physical storage modelphysical storage model describes what happens on the disks and in the circuits when files are stored– Storage media must be formatted before it can
store files• Formatting utilities divide the disk into tracks and
sectors
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4 Physical File Storage The file system
keeps track of the names and locations of files– NTFS
• Master File Table (MFT)
– FAT32• File Allocation Table
(FAT)
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4 Physical File Storage
Deleting a file changes the status of that file’s clusters to empty and removes the file nameremoves the file name from the index file– The file’s data is still there– File shredder software overwrites “empty” sectors
with random 1s and 0s
Files in the Windows Recycle Bin and similar utilities can be undeletedundeleted
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4 Physical File Storage
Fragmented files are stored in noncontiguous noncontiguous clustersclusters and decrease performance
Defragmentation utilities rearrange files so that they are stored in contiguous clusters
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4SECTION E
Backup SecurityBackup Security Backup Basics Data File Backup System Backup Boot and Recovery Disks
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4 Backup Basics
A backup stores the files needed to recover data that’s been wiped out by operator error, viruses, or hardware failures
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4 Backup Basics
Your backup schedule depends on how much data you can afford to lose
You should run an up-to-date virus check as the first step in your backup routine
The backup device you select depends on the value of your data, your current equipment, and your budget
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4 Backup Basics
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4 Data File Backup Most computers are equipped with a writable CD or writable CD or
DVD driveDVD drive with adequate storage capacity for a typical computer owner’s data files
Store all files to be backed up in the same location Back up Internet connection information, e-mail
folders, e-mail address book, favorite URLs, downloads and validation codes, and other configuration information
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4 Data File Backup
To restorerestore from a data file backup, you simply copy files from your backup to your hard disk
System Restore (Windows Me and XP) and System Protection (Windows Vista) are operating systems’ utilitiesoperating systems’ utilities that periodically set a restore point that is a snapshot of your computer settings
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4 System Backup
To make a backup, you can use backup software
Backup software is supplied with most tape drives and other backup devices
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4 System Backup
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4 System Backup A full backupfull backup makes a fresh copy of every file in the
folders you’ve specified for the backup A differential backupdifferential backup makes a backup of only those
files that were added or changed since your last full backup session
An incremental backupincremental backup makes a backup of the files that were added or changed since the last backup—not necessarily the files that changed from the last full backup
Most experts recommend that you keep more than one set of backups
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4 System Backup
Full, incremental, and differentialbackups each take a slightlydifferent approach to backingup files.
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4 Boot and Recovery Disks
A boot diskboot disk is a removable storage medium containing the operating system files needed to boot your computer without accessing the hard disk– Boots DOS
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4 Boot and Recovery Disks A recovery diskrecovery disk loads
hardware drivers and user settings as well as the operating system– Sometimes included with
new computer systems– The Windows XP
Backup utility creates a set of Automated System Recovery disks
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4 Boot and Recovery Disks You can create a custom recovery CDcustom recovery CD that contains
your computer’s current settings and device drivers Norton Ghost is a product of Symantec, which also
provides a more specialized recovery disk called the Symantec Recovery Disk
Certain PC manufacturers have pre-installed Norton Ghost and the recovery environment on some of their computers
Chapter 4 CompleteChapter 4 Complete
Operating Systems Operating Systems and File Managementand File Management