Distributed operating systems consist of multiple loosely coupled processors connected by a network, allowing for resource sharing, reliability, and computation speedup. Users interact with these systems through both network and local resources, with methodologies like data and computation migration to optimize performance. The document also discusses types of distributed systems, emphasizing their advantages, such as load balancing and improved access to specialized hardware and software.

1. DISTRIBUTED
OPERATING SYSTEMS
Presented by:
Ummiya Mohammedi.

2. nDistributed system is collection of loosely
coupled processors interconnected by a
communications network.
nProcessors are also called nodes,
computers, machines, hosts etc.
lSite is location where the processor
resides.
lGenerally a server has a resource a client
node that a different site wants to use.

5. Reasons for distributed systems
1.RESOURSE SHARING 2.RELIABILITY
3.COMPUTATION SPEEDUP 4.COMMUNICATION

6. Reasons for distributed systems
Resource sharing
Sharing and printing files at remote sites
Processing information in a distributed database
Using remote specialized hardware devices

7. Reliability
detect and recover from site failure, function
transfer, reintegrate failed site.

8. Computation speedup – load sharing or job migration
Reliability – detect and recover from site failure, function
transfer, reintegrate failed site

9. Communication –transfer of resources and computation
among processors.

10. All higher-level functions of a standalone
system can be expanded to encompass a
distributed system
Computers can be downsized, more
flexibility, better user interfaces and easier
maintenance by moving from large system
to multiple smaller systems performing
distributed computing

11. Types of Distributed Systems
Network Operating Systems
Distributed Operating Systems

12. 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)
Remote Desktop (Microsoft Windows)
Transferring data from remote machines to local machines, via
the File Transfer Protocol (FTP) mechanism
Users must change paradigms – establish a session, give network-
based commands
More difficult for users
Network-Operating Systems

14. 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
Via remote procedure calls (RPCs)
or via messaging system

15. Process Migration – execute an entire process, or parts of
it, at different sites by migrating it prior to or during the
process.
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.

16. Software preference – required software may be available
at only a particular site.
Data access – run process remotely, rather than transfer all
data locally. Consider the World Wide Web.
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.
Pros of Process Migration

18. 1.)What is Multiplicity of Machines?
2.)_________________ is used to transfer data from remote
machines to local machines.
3.)Difference between Data Migration and Computation
Migration.

19. 1.)What is Multiplicity of Machines?
Number of instances of a particular resourse.
2.) FTP is used to transfer data from remote machines to
local machines.
3.)Difference between Data Migration and Computation
Migration.
Data Migration is movement of data from one processor to
the other.
Computation Migration is movement of control of the
executing process.