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Lecture Operating system concepts - Chapter 15: Network structures

Lecture Operating system concepts (Sixth ed) - Chapter 15: Network structures. The main contents of this chapter include all of the following: Background, topology, network types, communication, communication protocol, robustness, design strategies. | Module 15: Network Structures I Background I Topology I Network Types I Communication I Communication Protocol I Robustness I Design Strategies Operating System Concepts 15.1 Silberschatz, Galvin and Gagne 2002 A Distributed System Operating System Concepts 15.2 Silberschatz, Galvin and Gagne 2002 Motivation I Resource sharing ✦ sharing and printing files at remote sites ✦ processing information in a distributed database ✦ using remote specialized hardware devices I Computation speedup – load sharing I Reliability – detect and recover from site failure, function transfer, reintegrate failed site I Communication – message passing Operating System Concepts 15.3 Silberschatz, Galvin and Gagne 2002 Network-Operating Systems I Users are aware of multiplicity of machines. Access to resources of various machines is done explicitly by: ✦ Remote logging into the appropriate remote machine. ✦ Transferring data from remote machines to local machines, via the File Transfer Protocol (FTP) mechanism. Operating System Concepts 15.4 Silberschatz, Galvin and Gagne 2002 Distributed-Operating Systems I Users not aware of multiplicity of machines. Access to remote resources similar to access to local resources. I Data Migration – transfer data by transferring entire file, or transferring only those portions of the file necessary for the immediate task. I Computation Migration – transfer the computation, rather than the data, across the system. Operating System Concepts 15.5 Silberschatz, Galvin and Gagne 2002 Distributed-Operating Systems (Cont.) I Process Migration – execute an entire process, or parts of it, at different sites. ✦ Load balancing – distribute processes across network to even the workload. ✦ Computation speedup – subprocesses can run concurrently on different sites. ✦ Hardware preference – process execution may require specialized processor. ✦ Software preference – required software may be available at only a particular site. ✦ Data