Multiple Processor SystemsMultiprocessor SystemsMultiprocessorsMultiprocessor Hardware (1)Multiprocessor Hardware (2)Multiprocessor Hardware (3)Multiprocessor Hardware (4)MulticomputersMulticomputer Hardware (1)Multicomputer Hardware (2)User Level Communication SoftwareRemote Procedure Call (1)Remote Procedure Call (2)Distributed Shared Memory (1)Distributed Shared Memory (2)Distributed Shared Memory (3)Distributed Systems (1)Distributed Systems (2)Network Hardware (1)Network Hardware (2)Network Services and Protocols (1)Network Services and Protocols (2)Document-Based Middleware (1)Document-Based Middleware (2)File System-Based Middleware (1)File System-Based Middleware (2)File System-Based Middleware (3)File System-Based Middleware (4)Shared Object-Based Middleware (1)Shared Object-Based Middleware (2)Shared Object-Based Middleware (3)Shared Object-Based Middleware (4)Shared Object-Based Middleware (5)Coordination-Based Middleware (1)Coordination-Based Middleware (2)Coordination-Based Middleware (3)Multiple Processor SystemsChapter 88.1 Multiprocessors 8.2 Multicomputers 8.3 Distributed systemsMultiprocessor Systems•Continuous need for faster computers–shared memory model–message passing multiprocessor–wide area distributed systemMultiprocessorsDefinition:A computer system in which two or more CPUs share full access to a common RAM4Multiprocessor Hardware (1)Bus-based multiprocessorsMultiprocessor Hardware (2)•UMA Multiprocessor using a crossbar switchMultiprocessor Hardware (3)•UMA multiprocessors using multistage switching networks can be built from 2x2 switches (a) 2x2 switch (b) Message formatMultiprocessor Hardware (4)•Omega Switching NetworkMulticomputers•Definition:Tightly-coupled CPUs that do not share memory•Also known as –cluster computers–clusters of workstations (COWs)Multicomputer Hardware (1)•Interconnection topologies(a) single switch(b) ring(c) grid(d) double torus(e) cube(f) hypercubeMulticomputer Hardware (2)•Switching scheme–store-and-forward packet switchingUser Level Communication Software•Minimum services provided–send and receive commands•These are blocking (synchronous) calls(a) Blocking send call(b) Nonblocking send callRemote Procedure Call (1)•Steps in making a remote procedure call–the stubs are shaded grayRemote Procedure Call (2)Implementation Issues•Cannot pass pointers–call by reference becomes copy-restore (but might fail)•Weakly typed languages–client stub cannot determine size•Not always possible to determine parameter types•Cannot use global variables–may get moved to remote machineDistributed Shared Memory (1)•Note layers where it can be implemented–hardware–operating system–user-level softwareDistributed Shared Memory (2)Replication(a) Pages distributed on 4 machines(b) CPU 0 reads page 10(c) CPU 1 reads page 10Distributed Shared Memory (3)•False Sharing•Must also achieve sequential consistencyDistributed Systems (1)Comparison of three kinds of multiple CPU systemsDistributed Systems (2)Achieving uniformity with middlewareNetwork Hardware (1)•Ethernet(a) classic Ethernet(b) switched EthernetComputer(a)(b)Network Hardware (2)The InternetNetwork Services and Protocols (1)Network ServicesNetwork Services and Protocols (2)•Internet Protocol•Transmission Control Protocol•Interaction of protocolsDocument-Based Middleware (1)•The Web–a big directed graph of documentsDocument-Based Middleware (2)How the browser gets a page1. Asks DNS for IP address2. DNS replies with IP address3. Browser makes connection 4. Sends request for specified page5. Server sends file6. TCP connection released7. Browser displays text8. Browser fetches, displays imagesFile System-Based Middleware (1)•Transfer Models(a) upload/download model(b) remote access model(a)(b)File System-Based Middleware (2)Naming Transparency(b) Clients have same view of file system(c) Alternatively, clients with different viewFile System-Based Middleware (3)•Semantics of File sharing–(a) single processor gives sequential consistency–(b) distributed system may return obsolete valueFile System-Based Middleware (4)•AFS – Andrew File System–workstations grouped into cells–note position of venus and viceClient's viewShared Object-Based Middleware (1)•Main elements of CORBA based system–Common Object Request Broker ArchitectureShared Object-Based Middleware (2)•Scaling to large systems–replicated objects–flexibility•Globe–designed to scale to a billion users–a trillion objects around the worldShared Object-Based Middleware (3)Globe structured objectShared Object-Based Middleware (4)•A distributed shared object in Globe–can have its state copied on multiple computers at onceShared Object-Based Middleware (5)Internal structure of a Globe objectCoordination-Based Middleware (1)•Linda–independent processes–communicate via abstract tuple space•Tuple–like a structure in C, record in Pascal1. Operations: out, in, read, evalCoordination-Based Middleware (2)Publish-Subscribe architectureCoordination-Based Middleware (3)•Jini - based on Linda model–devices plugged into a network–offer, use services•Jini Methods1. read2. write3. take4.
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