Design Issues of Distributed Computing

Design Issues of
Distributed Computing
Security
various resources of a computer
system must be protected against
destruction and unauthorized access.
Enforcing security in a distributed system is
more difficult because of the lack of a
single point of control and the use of
insecure networks for data communication
Reliability and fault tolerance
manages multiple resources, must be
designed properly to increase the system's
reliability
higher reliability needed to avoid faults,
tolerate faults and to detect and
recover from faults
Commonly used methods are fault
avoidance and fault tolerance.
Openness
Determines whether the system can be
extended in various ways without
disrupting existing system and services
should be flexible due: Ease of
modification & Ease of enhancement
Heterogeneity
heterogeneous distributed system consists
of interconnected sets of dissimilar
hardware or software systems
diversity causing heterogenous
distributed system far more difficult form
homogenous
heterogenous preferred as it provide
flexibility
Performance & scalability
overall performance should be better than
or at least equal to that of running the
same application on a singleprocessor
system
design principle should be considered
batch, cache, minimize copying of data,
minimize network traffic, take advantage of
finegrain parallelism for multiprocessing
Communication
essential part of distributed systems e.g.,
clients and servers must communicate for
request and response
Synchronous or blocking sender
waits for receiver to execute a receive
operation
Asynchronous or nonblocking
Transparency
no common clock among the multiple
processors
difficult task and requires that several
different aspects of transparency
messages could even be lost
delivery of messages is delayed
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