Goals
By Tariku Ahmed
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An operating system is a program that
manages computer hardwires. **
In other words
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OS resides on the computer hardware
Acts as the boss of everything that goes on the
computer above the BIOS
Manages in what order things get processed
using a predefined algorithm
Translates communication signals between the
hardware and the application program/user.
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DOS (3)
Symbian OS (18)
Windows 95 / 98 / Me /
DOS (24)
IBM (8)
UNIX (65)
Windows NT (89)
Linux OS (249)
Virtualization (69)
Windows Server 2003 (81)
Macintosh (104) •
VMS (10) •
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Windows Server 2008 (52)
Other (33)
Windows 2000
Professional (24)
Windows Vista (46)
Palm OS (16)
Windows 2000 Server (67)
Windows XP (73)
Sun Solaris (16) •
Windows 7 (31)
◦ The integration of
 Services
 Multiple computer system
 Distributed resource
 Distributed controls
Distributed Operating Systems & Algorithms, by
Randy Chow and Theodore Johnson, 1997.
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There are two parties who have a vested
interest on Distributed Operating System.
◦ System service provider
◦ User
◦ Example of things that we use every day which
employee Distributed System
 On demand Movie, Turbo Tax, Satellite navigation
systems (GPS)
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Both the user and system provider are
interested on having a system with following
characteristics.
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Efficiency
Flexibility
Consistency
Robustness
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Effective Business Recovery
◦ Effective data recovery
◦ Effective error handling
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Effective distributed system
◦ Load sharing, balanced and overlapped
communication
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Effective networking
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Avoid bottle neck
Redundancy in physical communication
Up to date communication system
Multiprocessing and multitasking
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No time constraint
No hardware dependency
Wide area coverage
Friendliness
◦ Easy and direct forward user interface with GUI
◦ Minimal training
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Easy retrieval
Major issues
◦ Lack of global information
◦ Potential replication
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Synchronized software update
◦ Example: tax software
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Predictable software behavior
Effective Business Recovery
◦ Effective data recovery
◦ Effective error handling
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Employee auto correcting/ programs with
high fault tolerance
◦ Database availability error – wait a couple of
seconds and resubmit
◦ Network error – reroute with the redundant line
◦ Notify customer – about outstanding issues and
give an accurate or educated guess recovery time.
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Distributed Operating Systems & Algorithms,
by Randy Chow and Theodore Johnson, 1997.
Abraham Silberschatz (2005) Operating
System Concepts 7th edition.
TCP/IP and Distributed System
by Vivek Acharya