Operating Systems
Dec 22, 2015
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
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
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 WindowsWindows ME (Millennium
Edition)Last of the Windows-on-DOS Targeted to home usersNo local security
2000
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
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