From Coulouris, Dollimore, Kindberg and Blair Distributed Systems: Concepts and Design Edition 5, © Addison-Wesley 2012 Design of Parallel and Distributed Systems by Dr. Sarmad Sadik

Course Outline  Characterization of Distributed Systems  System Models  Remote Invocation  Indirect Communication  Peer to peer systems  Distributed File Systems  Advance topics in Research 2

Books Text Book: Distributed Systems : Concepts and Design By: George Coulouris, Jean Dollimore and Tim Kindberg: 5 th Edition Reference Book: Distributed Systems: Principles and Paradigms by Andrew S Tanenbaum and Maarten van Steen, 2 nd Edition 3

Grading Assignments – 10% Quizzes – 10% OHTs– 15% + 15% Final Exam – 50% 4

Introduction  Introduction of distributed systems  Concurrency  No global clock  Independent failures  Examples of distributed systems 5

Examples of distributed systems  Web search  Massively multiplayer online games (MMOGs)  Financial trading 6

7 Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Selected application domains and associated networked applications Finance and commerceeCommerce e.g. Amazon and eBay, PayPal, online banking and trading The information society Web information and search engines, ebooks, Wikipedia; social networking: Facebook and MySpace. Creative industries and entertainment online gaming, music and film in the home, user- generated content, e.g. YouTube, Flickr Healthcarehealth informatics, online patient records, monitoring patients Educatione-learning, virtual learning environments; distance learning Transport and logisticsGPS in route finding systems, map services: Google Maps, Google Earth ScienceThe Grid as an enabling technology for collaboration between scientists Environmental managementsensor technology to monitor earthquakes, floods or tsunamis

8 Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 An example financial trading system

Trends in distributed systems  The emergence of pervasive networking technology  The emergence of ubiquitous computing coupled with the desire to support user  Mobility in distributed systems  The increasing demand for multimedia services  The view of distributed systems as a utility 9

Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 A typical portion of the Internet

Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Portable and handheld devices in a distributed system

12 Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Cloud computing

Challenges  Heterogeneity  Openness  Security  Scalability  Failure handling  Concurrency  Transparency 13

Heterogeneity  Networks  Computer hardware  Operating systems  Programming languages  Implementations by different developers  Middleware  Heterogeneity and mobile code  Virtual machine 14

Openness  Open systems are characterized by the fact that their key interfaces are published  Uniform communication mechanism  Open distributed systems can be constructed from heterogeneous hardware and software  But the conformance of each component to the published standard must be carefully tested and verified if the system is to work correctly. 15

Security Confidentiality, Integrity, Availability Denial of service attacks Security of mobile code 16

Scalability  Controlling the cost of physical resources  Controlling the performance loss  Preventing software resources running out  Avoiding performance bottlenecks 17

Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Growth of the Internet (computers and web servers) DateComputersWeb serversPercentage 1993, July 1,776, , July6,642,00023, , July19,540,0001,203, , July56,218,0006,598, , July125,888,19731,299, ,298, , July 2005, July ~200,000, ,284,18767,571,

Failure handling  Detecting failures  Masking failures  Tolerating failures  Recovery from failures  Redundancy 19

Concurrency  Concurrent resource sharing  Transactions control  Synchronization 20

Transparencies Access transparency: enables local and remote resources to be accessed using identical operations. Location transparency: enables resources to be accessed without knowledge of their physical or network location (for example, which building or IP address). Concurrency transparency: enables several processes to operate concurrently using shared resources without interference between them. Replication transparency: enables multiple instances of resources to be used to increase reliability and performance without knowledge of the replicas by users or application programmers.

Transparencies Failure transparency: enables the concealment of faults, allowing users and application programs to complete their tasks despite the failure of hardware or software components. Mobility transparency: allows the movement of resources and clients within a system without affecting the operation of users or programs. Performance transparency: allows the system to be reconfigured to improve performance as loads vary. Scaling transparency: allows the system and applications to expand in scale without change to the system structure or the application algorithms.

Quality of service The main nonfunctional properties of systems that affect the quality of the service experienced by clients and users are  Reliability  Security  Performance.  Adaptability 23

Case study: The World Wide Web  HTML, URL, URI, HTTP  Web services  Semantic Web 24

Instructor’s Guide for Coulouris, Dollimore, Kindberg and Blair, Distributed Systems: Concepts and Design Edn. 5 © Pearson Education 2012 Web servers and web browsers Internet Browsers Web servers standards faq.html File system of

Assignment 1  Compare the cloud computing concept with traditional computing.  How cloud computing addresses the challenges of heterogeneity, openness, scalability and transparency?  Deadline: 24 th Sep,

Thank you ! 27