1 / 117

Modulo I Introdução aos Sistemas Distribuídos

This course provides an introduction to distributed systems, covering topics such as hardware, client-server paradigm, networking, and client-server communication. It explores the motivations behind distributed systems and discusses scalability, transparency, multitiered architectures, and types of distributed operating systems.

donnam
Download Presentation

Modulo I Introdução aos Sistemas Distribuídos

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Modulo I Introdução aos Sistemas Distribuídos Prof. Ismael H F Santos Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 1

  2. Bibliografia • Sistemas Distribuídos • Santos,F., H., Ismael; Notas de Aula, 2005 • Sistemas Operacionais e Programação Concorrente • Toscani e outros, Editora sagra-luzzatto • Fundamentos de Sistemas Operacionais • Silberschatz, Abraham, Galvin, Peter, Gagne, G., LTC • Sistemas Distribuídos • Andrew S. Tanenbaun; Prentice Hall • Operating System Concepts: Internals and Design Principles • Williiam Stallings, Prentice Hall Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 2

  3. Ementa • Distributed Systems • Hardware for Distibuted Systems • Client Server Paradigm • Networking • Client Server Communication Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 3

  4. SOA Distributed Systems Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 4

  5. Motivation • Distributed system is collection of loosely coupled processors interconnected by a communications network • Processors called nodes, computers, machines, hosts • Site is location of the processor • Reasons for distributed systems • Resource sharing • sharing and printing files at remote sites • processing information in a distributed database • using remote specialized hardware devices • Computation speedup – load sharing • Reliability – detect and recover from site failure, function transfer, reintegrate failed site • Communication – message passing Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 5

  6. A Distributed System Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 6

  7. Definition of a Distributed System (2) • A distributed system organized as middleware. • Note that the middleware layer extends over multiple machines. 1.1 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 7

  8. Transparency in a Distributed System Different forms of transparency in a distributed system. Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 8

  9. Multitiered Architectures (1) • Alternative client-server organizations (a) – (e). 1-29 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 9

  10. Multitiered Architectures (2) • An example of a server acting as a client. 1-30 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 10

  11. Scalability Problems Examples of scalability limitations. Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 11

  12. Scaling Techniques (1) 1.4 The difference between letting: • a server or • a client check forms as they are being filled Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 12

  13. Scaling Techniques (2) 1.5 An example of dividing the DNS name space into zones. Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 13

  14. Types of Distributed Operating Systems • Network Operating Systems • Distributed Operating Systems Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 14

  15. Network-Operating Systems • Users are aware of multiplicity of machines. Access to resources of various machines is done explicitly by: • Remote logging into the appropriate remote machine (telnet, ssh) • Transferring data from remote machines to local machines, via the File Transfer Protocol (FTP) mechanism Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 15

  16. Distributed-Operating Systems • Users not aware of multiplicity of machines • Access to remote resources similar to access to local resources • Data Migration – transfer data by transferring entire file, or transferring only those portions of the file necessary for the immediate task • Computation Migration – transfer the computation, rather than the data, across the system Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 16

  17. Distributed-Operating Systems (Cont.) • 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 access – run process remotely, rather than transfer all data locally Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 17

  18. Network Structure • Local-Area Network (LAN) – designed to cover small geographical area. • Multiaccess bus, ring, or star network • Speed  10 megabits/second, or higher • Broadcast is fast and cheap • Nodes: • usually workstations and/or personal computers • a few (usually one or two) mainframes Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 18

  19. Depiction of typical LAN Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 19

  20. Network Types (Cont.) • Wide-Area Network (WAN) – links geographically separated sites • Point-to-point connections over long-haul lines (often leased from a phone company) • Speed  100 kilobits/second • Broadcast usually requires multiple messages • Nodes: • usually a high percentage of mainframes Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 20

  21. Communication Processors in a Wide-Area Network Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 21

  22. SOA Hardware Concepts Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 22

  23. Hardware Concepts 1.6 Different basic organizations and memories in distributed computer systems Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 23

  24. Multiprocessors • A bus-based multiprocessor • A crossbar switch • An omega switching network Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 24

  25. Homogeneous Multicomputer Systems • Grid • Hypercube 1-9 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 25

  26. Software Concepts • DOS (Distributed Operating Systems) • NOS (Network Operating Systems) • Middleware Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 26

  27. Uniprocessor Operating Systems • Separating applications from operating system code through a microkernel. 1.11 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 27

  28. Multicomputer Operating Systems • General structure of a distributed system as middleware. 1-22 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 28

  29. Multicomputer Operating Systems (2) • Alternatives for blocking and buffering in message passing. 1.15 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 29

  30. Multicomputer Operating Systems • Relation between blocking, buffering, and reliable communications. Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 30

  31. Distributed Shared Memory Systems • Pages of address space distributed among four machines • Situation after CPU 1 references page 10 • Situation if page 10 is read only and replication is used Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 31

  32. Distributed Shared Memory Systems (2) • False sharing of a page between two independent processes. 1.18 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 32

  33. Network Operating System (1) • General structure of a network operating system. 1-19 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 33

  34. Network Operating System (2) • Two clients and a server in a network operating system. 1-20 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 34

  35. Network Operating System (3) • Different clients may mount the servers in different places. 1.21 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 35

  36. Positioning Middleware • General structure of a distributed system as middleware. 1-22 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 36

  37. Middleware and Openness • In an open middleware-based distributed system, the protocols used by each middleware layer should be the same, as well as the interfaces they offer to applications. 1.23 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 37

  38. Comparison between Systems • A comparison between multiprocessor operating systems, multicomputer operating systems, network operating systems, and middleware based distributed systems. Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 38

  39. Processing Level • The general organization of an Internet search engine into three different layers 1-28 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 39

  40. Multitiered Architectures (1) • Alternative client-server organizations (a) – (e). 1-29 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 40

  41. Multitiered Architectures (2) • An example of a server acting as a client. 1-30 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 41

  42. Modern Architectures • An example of horizontal distribution of a Web service. 1-31 Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 42

  43. SOA Client-Server Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 43

  44. Software and hardware service layers in distributed systems Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 44

  45. Clients invoke individual servers Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 45

  46. A service provided by multiple servers Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 46

  47. Web proxy server Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 47

  48. A distributed application based on peer processes Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 48

  49. Web applets Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 49

  50. Compute server Network computer or PC Application network Thin Process Client Thin clients and compute servers Prof. Ismael H. F. Santos - ismael@tecgraf.puc-rio.br 50

More Related