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Distributed Systems [220]

collection of processors
each processor has its own local memory
processors communicate through communication lines
processors do not share a clock
distributed systems (DS) provide users with:
resource sharing
computation speedup
reliability
communication
network OS: users are aware of multiplicity of machines
manually specify operations
remote login: telnet cs.utexas.edu
remote file transfer: ftp cs.utexas.edu
distributed OS: users are not aware

DS: Advantages/Disadvantages [221]

advantages over centralized systems
economics, speed, inherent distribution, reliability, incremental
advantages over isolated (personal) computers
data sharing, device sharing, communication, flexibility
disadvantages
little software, network saturation, security

DS: Topology [222]

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basic cost: how expensive to link various sites in system?
communication cost: how long does it take to send a message?
reliability: if site fails, can remaining sites still communicate?

Subsections

- Systems/Networks
- Distributed Coordination

Next: Systems/Networks Up: 4560 Previous: File Management Contents

Ted Billard 2001-11-17