Operating Systems

Operating Systems•Activities performed by the operating system:

–Perform common computer hardware functions

–Provide a user interface and input/output management

–Provide a degree of hardware independence

–Manage system memory

–Manage processing tasks

–Provide networking capability

–Control access to system resources

–Manage files

Operating Systems cont’d•Hardware independence:

–Application program interface (API):

•Allows applications to make use of the operating system

•Memory management:

–Allows computer to execute program instructions effectively and to speed processing

Operating Systems cont’d

User Interfaces •User interface and input/output management:

–User interface:

•Allows individuals to access and command the computer system

–Command-based user interface (CLI):

•Requires that text commands be given to the computer to perform basic activities

–Graphical user interface (GUI):

•Uses icons and menus displayed on screen to send commands to the computer system

Contemporary Operating Systems

•Microsoft PC operating systems:

–Windows XP

–Windows 7

–Windows 8

•Apple computer operating systems:

–Wintel

–Mac OS X

•Linux:

–Red Hat Linux

–Caldera OpenLinux

Workgroup Operating Systems•Windows Server:

–Can be used to prevent unauthorized disclosure of information

•UNIX:

–Can be used on many computer system types and platforms

•Red Hat Linux:

–Can manage a cluster of up to eight servers

•Mac OS X Server:

–Includes support for 64-bit processing

Enterprise Operating Systems•z/OS:

–IBM’s first 64-bit enterprise OS

•HP-UX and Linux:

–HP-UX:

•Robust UNIX-based OS from Hewlett-Packard

•Supports Internet, database, and business applications on server and mainframe enterprise systems

MS-DOS 6.221994 Last version

Windows 8 Command Prompt

Windows 8Standard-User Command Prompt

The Windows Command Prompt is Not MS-DOS

MS-DOS was a small OS It had no security featuresIt had a simple CLI and no native GUIThe MS-DOS command interpreter was

command.comThe Command Prompt command

interpreter is cmd.exeCommand Prompt is subject to

Windows security

Microsoft Windows

GUI on top of MS-DOS

1985-1990 Versions 1.0, 2.0, 3.0

1992 Windows 3.1

1992 Windows for Workgroups 3.1 Included networking.

Microsoft Windows

Entirely new OS with security features1993 Windows NT 3.1Server OS1994 NT 3.5 Server and Workstation1996 NT 4.0 Server and Workstation

Windows NT 4.0

Microsoft Windows

1995 Windows 95Desktop OS with GUI on DOSImproved GUINo local security

Microsoft Windows

1998 Windows 98Desktop OS with GUI on DOSImproved GUINo local security

Microsoft WindowsWindows ME (Millennium

Edition)Last of the Windows-on-DOS Targeted to home usersNo local security

2000

Microsoft Windows

2000

Windows 2000

New GUI on NT kernel

Included local security features

Microsoft Windows

2001Windows XPOn NT kernel, but targeted to desktopVery popular for over a decade

Microsoft Windows

2007Windows VistaNot a successful OS

Microsoft Windows

2009Windows 7Many improvementsRedesigned desktop

Microsoft Windows

2012Windows 8Two GUIs: Modern and DesktopSupports new hardware

Modern GUI Start Screen

UNIX and LinuxOperating Systems

UNIX/Linux is a multi-user system

UNIX/Linux is a multitasking systemCan execute more than one program at a

time

UNIX/Linux is a portable operating systemUsed in many computing environments

Apple Mac OS X

2001- PresentProprietary—Only runs on MacsBased on UNIX kernelGUI and optional CLI

Linux

1991Project of Linus Benedict TorvaldsOpen-sourceAvailable in free distributionsOptional GUIs

Linux can have a GUIThe KDE GUI in Fedora

The Unity GUI in Ubuntu

Job ManagementSchedulingPrinting

Controls order and time in which programs run.

Task ManagementControls focusAllows user to switch between

tasksCurrent window has focusPrograms have many

processes

Required for Multitasking

File ManagementManages storage of dataFile system is logical structure

on storage deviceFormatting writes file system

to storage device

Read, write, modify data

File ManagementFileFolder/directory

File system logical structure

Device ManagementDevice driver for each

device/OSControls hardware devices

Security

Password-protected authentication

4 key components of an O/SProcess Management (section

on processes) Memory Management (sections

on memory allocation and virtual memory)

I/O Management (sections on resources, synchronization, and deadlocks)

File Management (section on file management)