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7 distributed and real systems

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7 distributed and real systems

  1. 1. Basics of Operating Systems : Distributed and Real systems• HOME PREVIOUS TOPIC NEXT• PREVIOUS QUESTION PAPERS FOR OS• CPP TUTORIALS 1
  2. 2. Basics of Operating Systems : Distributed and Real systems 2
  3. 3. RecapIn the last class, you have learnt about• Multiprogramming• Time Sharing 3
  4. 4. ObjectivesOn completion of this period, you would be able to know• Distributed Systems• Real Time Systems 4
  5. 5. Distributed Systems• Distributed systems are loosely coupled systems• A Distributed computer system is a collection of autonomous computer systems• Distributed systems communicate with one another through various communication lines like high speed buses or telephone lines• The processors in a distributed system may vary in size and function – Example: small microprocessors, workstations , minicomputer and large general purpose computers 5
  6. 6. Distributed Systems (contd..)
  7. 7. Distributed System• Processors in distributed systems are referred by no. of different names like, sites, nodes, computers, etc.• Important reasons for building distributed systems are – Resource sharing – Computation speedup – Reliability – Communication• The key objective of a distributed operating system is transparency• Ideally, component and resource distribution should be hidden from users and applications programs unless they explicitly demand 7
  8. 8. Distributed System• A distributed operating system governs the operations of a distributed computer systems and provides a virtual machine abstraction to its users• Distributed operating system usually provides the means for system-wide sharing of resources, such as computational capacity, files and I/O devices• Distributed operating system facilitates access to remote resources, communication with remote process and distribution of computation 8
  9. 9. Real-Time System• Real-time systems has well defined, fixed time constraints• Processing must be done with in the defined constraints, or the system will fail• For example: • It would not do for a robot arm to be instructed to halt after it had smashed into the car it was building 9
  10. 10. Real-Time System
  11. 11. Real-Time System• Real-time system is used as a control device in a dedicated application• Sensors bring data to computers• Computer analyze data and adjust controls to modify the sensor inputs• Example: • Scientific experiments, medical imaging systems, industrial control systems etc..• Real-time system functions correctly only if it returns the correct result within its time constraints 11
  12. 12. Real-Time System• A primary objective of real-time systems is to provide quick event - response times, thus meet the scheduling dead lines• User convenience and resource utilization are of secondary concern to real- time system designers• Real-time operating systems usually rely on some specific policies and techniques for doing their job 12
  13. 13. Real-Time System• Memory management in real-time systems is comparatively less demanding then in other types of multiprogramming systems• The primary reason for this is that many process permanently reside in memory in order to provide quick response time 13
  14. 14. Real-Time System• File management is usually found only in larger installation of real-time systems• In fact, some embedded real-time systems, such as an onboard automotive controller, may not even have any secondary storage• These include protection and access control 14
  15. 15. Summary• A primary objective of real-time systems is to provide quick event - response times, and thus meet the scheduling dead lines• User convenience and resource utilization are of secondary concern to real- time system designers• A distributed computer system is a collection of autonomous computer systems capable of communication and cooperation via their hardware and software interconnections 15
  16. 16. Frequently Asked Questions1. Explain about Real Time Operating System2. Explain about Distributed Operating System 16
  17. 17. Quiz1. File management is usually found only in larger installation of real-time systems Yes No 17
  18. 18. Quiz2. A distributed computer system is a collection of autonomous computer systems capable of communication and cooperation via their hardware and software interconnections Yes No 18
  19. 19. Other subject materials• Web designing• Micro processors• C++ tutorials• javahome 19

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