Download Operating Systems

Operating Systems
Dr. Fred Mtenzi
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Teaching Approach
• Lectures and labs
– Wed 11.00 – 12.00 noon (Lecture)
– Wed 14.00 – 15.00 am (Lab)
– Thur 12.00 – 13.00 pm (Lecture)
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Assessment methods
• Written examination 70%
• Continuous assessment 30%
– Written test end of first semester.
– Linux lab test.
– Shell programming.
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References
• Understanding Operating Systems, 3rd Ed, I.M. Flynn and A. Mclver
McHoes, (2001) PWS Publishing Company.
• Operating Systems: Internals and design principles (2001), 4th Ed,
William Stallings, Prentice Hall.
• Modern Operating Systems, Andrew Tanenbaum(2001), 2nd Edition,
Prentice Hall.
• Operating Systems Design And Implementation
2nd Edition Andrew Tanenbaum, Albert Woodhull (1997), Prentice
Hall.
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References
• Operating Systems Modern Perspective
2nd Edition Gary Nutt (2000), Prentice Hall.
• Operating Systems A Systematic View
5th Edition William Davis, T.M. Rajkumar (2001), Prentice Hall.
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Operating Systems Theory
• To understand the OS is to understand the workings of the
entire computer system, because it is the OS that managers
each and every piece of hardware and software.
• An OS is the ‘executive manager’, the part of the
computing system that manages all of the hardware and all
of the software. To be specific, it controls every file, every
device, every section of main memory, and every
nanosecond of processing time.
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Operating Systems Theory
• The OS has four subsystem managers: memory manager,
processor manager, device manager and file manager.
• Each of the subsystem managers must perform these tasks:
– Monitor its resources continuously.
– Enforce the policies that determine who gets what, and
how much.
– Allocate the resources when its appropriate.
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Operating Systems Theory
– Deallocate the resource – reclaim it when appropriate.
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Understanding Operating Systems
Part II: Operating Systems in Practice
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MS-DOS Operating System
Windows 2000
UNIX/Linux Operating System
OpenVMS Alpha Operating System
IBM OS/390 Operating System
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Overview
• Introduction
• Operating System
Components
• Machine Hardware
• Types of Operating
Systems
• Brief History of Operating
Systems Development
• Conclusion
Software
Components
Developed
Hardware
Components
Developed
Operating Systems
Developed
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Components of an Operating System
Operating system – part of the computing system that
manages all of the hardware and all of the software
– Controls every file, device, section of main memory &
every nanosecond of processing time
Operating system
consists of
• Memory manager
• Processor manager
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Device manager
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File manager
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Subsystems Must Work
With Each Other
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Tasks Performed by Each Subsystem
1. Monitor its resources continuously
2. Enforce the policies that determine who gets what, when
and how much
3. Allocate the resource when appropriate
4. Deallocate the resource (reclaim it) when appropriate
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Machine Hardware
• Memory chips
• Input/output devices (monitor, keyboard, printer)
• Storage devices (disks, magnetic tape, card readers, drums)
• Central Processing Unit (Arithmetic Logic Unit, registers,
internal control, bus control)
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Types of Operating Systems
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Batch (simple and multi-programmed)
Interactive (time-sharing)
Real-time systems
Hybrid systems (combination of batch and interactive)
Parallel (tightly coupled)
Distributed (loosely coupled)
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Brief History of Operating
Systems Development
Second Generation
Job scheduling, JCL, faster
I/O, spooling, batch, files
1940
1955
Recent Developments
Distributed computing,
personal computers, highspeed communication,
multi-media
1965
1980
First Generation
Third Generation
Vacuum tube, single user,
early operating systems
Shared processing,
multiprogramming, virtual
memory, DBMS
1990
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Key Terms
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batch system
central processing unit
device manager
file manager
firmware
hardware
hybrid system
interactive system
main memory
mainframe
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memory manager
microcomputer
minicomputer
multiprocessing
networking
operating system
processor manager
real-time system
software
supercomputer
workstation
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