distributed systems
Download
Skip this Video
Download Presentation
Distributed Systems

Loading in 2 Seconds...

play fullscreen
1 / 13

Distributed Systems - PowerPoint PPT Presentation


  • 140 Views
  • Uploaded on

Distributed Systems. Multiple software components on multiple computers running as a single system. Computers can be close or distant Homogeneous or heterogeneous Managed as a unit or disparate

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Distributed Systems' - candice


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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
distributed systems
Distributed Systems
  • Multiple software components on multiple computers running as a single system.
    • Computers can be close or distant
    • Homogeneous or heterogeneous
    • Managed as a unit or disparate
  • Distribution will only grow as networks and computing devices become even more ubiquitous, wireless

Distributed Systems

distributed systems examples
Distributed SystemsExamples
  • Domain Name service (DNS)
  • World Wide Web
  • Campus-wide File Systems
  • Email services: POP3, IMAP, MS Exchange
  • ATM networks
  • Electronic stock-trading “floors”
  • “Smart” house

Distributed Systems

distributed systems features
Distributed SystemsFeatures
  • Resource Sharing
    • Of disks, printers, software packages, etc.
  • Openness
    • Supports addition of new (non-proprietary) resources; heterogeneous components
  • Concurrency
    • Multiple communicating processes

Distributed Systems

distributed systems features4
Distributed SystemsFeatures
  • Scalability
    • Capacity can be “easily” increased
  • Fault Tolerance
    • Continued operation in the face of limited (hw/sw) failure
  • Transparency
    • Distribution practically invisible to users

Distributed Systems

distributed systems disadvantages
Distributed SystemsDisadvantages
  • Complexity
    • Harder to test
    • System performance depends on network, relative speed of computers, resource location relative to computers
    • Additional design issues

Distributed Systems

client server architectures
Client-server Architectures
  • Client processes make requests of server processes
  • Can often be structured in (three) layers
    • Presentation
    • Application processing
    • Data management
  • See Section 11.2 of Sommerville for details

Distributed Systems

client server architectures7
Client-server Architectures
  • Two-tier (c-s architecture)
    • Thin client
      • Presentation only
    • Fat client
      • Presentation and processing

Distributed Systems

two tier architectures thin or fat clients
Two-tier ArchitecturesThin or Fat Clients?
  • Thin clients
    • Increases load on server, network
    • Doesn’t scale as well
  • Fat clients
    • Reduce processing load on server
    • Increases load on clients
    • Harder to manage; applications often evolve

Distributed Systems

two tiers good three tiers better
“Two tiers good, three tiers better”
  • Three-tier (c-s architecture)
    • Distinct processes for each layer (client-server-server)
    • Server processes easily split onto distinct processors, if/when necessary
    • More scalable (can replicate processing servers)
    • E.g. database-backed web service (flight search/reservation system, web banking)

Distributed Systems

database based www service

Web browser

Web browser

Web server

Web server

Web browser

Web browser

Database-based WWW service

Web browser

DBMS

Web server

Web browser

Web browser

Distributed Systems

peer to peer architecture
Peer-to-peer Architecture
  • Communication among the peers (“client” no longer appropriate) encouraged
  • Pure Peer-to-Peer: no dedicated server processes at all
  • Hybrid examples: Napster, ICQ, AIM
  • Pure examples: Gnutella, Morpheus

Distributed Systems

distributed object architectures
Distributed Object Architectures
  • Object-oriented design
    • No client/server distinction
    • System as a collection of distributed objects
    • Objects map to processes, not (necessarily) processors
    • Communication via middleware (a “software bus”)

Distributed Systems

distributed object architectures middleware
Distributed Object ArchitecturesMiddleware
  • CORBA† (Common Object Request Broker Architecture)
  • Java RMI (Remote Method Invocation)
  • DCOM (Distributed Component Object Model)
  • .NET

†See Section 11.4 of Sommerville for details

Distributed Systems

ad