COMPUTERS: TOOLS FOR AN INFORMATION AGE Chapter 3 Operating Systems.

COMPUTERS:TOOLS FOR AN INFORMATION AGE

Chapter 3Operating Systems

Operating Systems: Hidden Software

A set of programs that lies between applications software and the hardware

Objectives of Operating Systems

1. Manages computer’s resources (CPU, peripheral devices)

2. Establishes a user interface Determines how user interacts with operating system

3. Provides and executes services for applications software

User Interface (UI)

The most common user interfaces are:

Command-line Text only E.g. DOS

Graphical User Interface (GUI) Images, icons, menus, drag and drop E.g. Windows, Mac OS

Systems Software

All programs related to coordinating computer operations

Examples: Operating systems Programming language translators

Convert program code to machine-readable form Utility programs

Perform secondary chores (tasks)

Kernel

Manages the operating systemLoaded from hard drive into memory when

computer is booted Booting refers to starting the computer

Loads other operating system programs from disk storage as needed Other programs referred to as nonresident

Uses of Operating Systems

Operating systems are used in: Personal computers Networks Large computers

Operating Systems for PCs

Platform: combination of computer hardware and operating system software (personal computer)

Common Platforms: MS-DOS Windows MAC OS Unix Linux

MS-DOS

Uses a command-line interface Screen provides prompts for user User types commands

Largely replaced by graphical user interfaces

Not user-friendly

MS Windows

Uses a graphical user interface (GUI)

A layer added “on top” of DOS Separates operating system from user Makes operating system easier to use Called a shell

Graphical User Interface

User clicks an icon to perform tasks

Start Menu in lower left corner launches programs

Use menus to activate commands

Windows Features

Long file names (up to 255 characters)

Plug and Play Makes installing hardware components easier

Windows Family

Windows 95Windows 98Windows MEWindows XPWindows 7Windows CEWindows MobileWindows NTWindows 2000Windows Server 2003Windows Server 2008

Apple MAC OS

Designed for the Macintosh computerFirst commercially successful GUI

Has served as the model for Windows and other GUI products developed since then

Linux

Uses command-line interface Many companies have created a GUI to work with Linux

Open-source concept Source code is free Users can download, change, and distribute the software

More stable than Windows

Applications relatively scarce (uncommon)

Network Operating Systems

Examples: Windows NT Server Windows 2000 Server Windows Server 2003 Windows Server 2008 Windows .NET Server Novell Netware Unix Linux

Utility Programs

Perform secondary chores (tasks)

Examples: File manager File compression Others

File Manager

Stores files in a hierarchical directory structureWindows uses Windows Explorer

File Compression

Reduces amount of space a file requires Makes file take up less space on disk Takes less time to transmit across communication

lines

Other Utility Programs

Backup and Restore Backup: make copies of disks and store in a safe place Restore: restore files from backups

Disk defragmenter: reorganizes disk so all files are stored in contiguous locations

Device driver: handles commands for devices, such as printers and storage devices