Distributed Systems CIS 505: Software Systems Introduction ...

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11CIS 505: Software SystemsIntroduction to Distributed SystemsInsup LeeDepartment of Computer and Information ScienceUniversity of PennsylvaniaCIS 505, Spring 2007CIS 505, Spring 2007Distributed Systems2Distributed Systems Why Distributed Systems ?oavailability of powerful yet cheap microprocessors (PCs,workstations, PDAs, embedded Systems , etc.)ocontinuing advances in communication technology What is a Distributed system ?oA Distributed system is a collection of independentcomputers that appear to the users of the system as a singlecoherent 505, Spring 2007Distributed Systems3Examples The world wide web information, resourcesharing Clusters, Network of workstations Distributed manufacturing system ( ,automated assembly line) Network of branch office computers -Information system to handle automaticprocessing of orders Network of embedded Systems New Cell processor (PlayStation 3)CIS 505, Spring 2007Distributed Systems4Advantages and disadvantages AdvantagesoEconomicsoSpeedoInherent distributionoReliabilityoIncremental growth DisadvantagesoSoftwareoNetworkoMore components to failoSecurity2CIS 505, Spring 2007Distributed Systems5Organization of a Distributed SystemA Distributed system organized as that the middlewar

2) at a lower level, make the system look transparent to programs. 1) and 2) requires uniform interfaces such as access to files, communication. CIS 505, Spring 2007 Distributed Systems 8 Transparency in a Distributed System Different forms of transparency in a distributed system. Persistence Hide whether a (software) resource is in memory or ...

  System, Distributed, Distributed system