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 6.22
1994 Last version
Windows 8
Command
Prompt
Windows 8
Standard-User
Command Prompt
The Windows Command Prompt is Not MS-DOS
 MS-DOS was a small OS
 It had no security features
 It had a simple CLI and no native GUI
 The MS-DOS command interpreter was
command.com
 The Command Prompt command interpreter is
cmd.exe
 Command 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 features
1993 Windows NT 3.1Server OS
1994 NT 3.5 Server and Workstation
1996 NT 4.0 Server and Workstation
Windows NT 4.0
Microsoft Windows
1995 Windows 95
Desktop OS with GUI on DOS
Improved GUI
No local security
Microsoft Windows
1998 Windows 98
Desktop OS with GUI on DOS
Improved GUI
No local security
Microsoft Windows
2000
 Windows ME (Millennium Edition)
 Last of the Windows-on-DOS
 Targeted to home users
 No local security
Microsoft Windows
2000
Windows 2000
New GUI on NT kernel
Included local security features
Microsoft Windows
2001
Windows XP
On NT kernel, but targeted to desktop
Very popular for over a decade
2007
Windows Vista
Not a successful OS
Microsoft Windows
Microsoft Windows
2009
Windows 7
Many improvements
Redesigned desktop
Microsoft Windows
2012
Windows 8
Two GUIs: Modern and Desktop
Supports new hardware
Modern GUI Start
Screen
UNIX and Linux
Operating Systems
 UNIX/Linux is a multi-user system
 UNIX/Linux is a multitasking system
 Can execute more than one program at a time
 UNIX/Linux is a portable operating system
 Used in many computing environments
Apple Mac OS X
2001- Present
Proprietary—Only runs on Macs
Based on UNIX kernel
GUI and optional CLI
Linux
1991
Project of Linus Benedict Torvalds
Open-source
Available in free distributions
Optional GUIs
Linux can have
a GUI
The KDE GUI in Fedora
The Unity GUI in Ubuntu
Job Management
Controls order
and time in which
programs run.
 Scheduling
 Printing
Task Management
Required for
Multitasking
 Controls focus
 Allows user to switch between tasks
 Current window has focus
 Programs have many processes
File Management
Read, write,
modify data
 Manages storage of data
 File system is logical structure on storage
device
 Formatting writes file system to storage
device
File Management
File system logical
structure
 File
 Folder/directory
Device Management
Controls hardware
devices
 Device driver for each device/OS
Security
 Password-protected authentication
4 key components of an O/S
 Process 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)