1exam Flashcards
It is a main motivation for contructing distributed system
The sharing of resources
When all computer systems can fail and the responsibility of system designers is to plan for the consequences of it, is called
Independent failures
It is one in which components located at networked computers communicate and coordinate
A distributed systems
They are three examples of distributed systems
Internet, Intranet, and ubiquitous computing
It is the capacity of system to handle shared resources can be increased by adding more resources to the network
Concurrency
Its role is to protect an intranet by preventing unauthorized messages leaving or entering
Firewall
The portability of many of these devices, together with their ability to
connect conveniently to networks in different places, make this type of
computing possible.
Mobile computing
It is the harnessing of many small, cheap computacional devices that are
present in user physical environments, including the home, office and
elsewhere.
Ubiquitous computing
It is a portion of the Internet that is separately administered and has a
boundary that can be configured to enforce local security polices.
An intranet
It is a vast interconnected collection of computer networks of many
different types, programs running on the computers connected to it
interact by passing messages, employing a common means of
communication.
The internet
They are three of the challenges in
distributed systems that must be meet by
designers to be aware of them are:
Heterogeneity, Openness and Scalability
The Web is based on three main standard
technological components:
HTML, URL, and the client-server system architecture
They are transparencies that must meet
the distributed systems.
Location, failure and performance.
This challenge is defined as the
concealment from the user and the
application programmer of the separation
of components in a distributed system, so
that the system is perceived as a whole
rather than as a collection of independent
components
Transparency
In this challenge both services and
applications provide resources that can be
shared by clients in a distributed systems.
Concurrency
This is the lowest-layer which bring the system’s programming
interface up to a level that facilities communication and
coordination between processes.
System Platform
It is concerned with the placement of a distributed system parts
and the relationships between them.
The architectural model of DS
It is a layer of software whose purpose is to mask heterogeneity
and provide a convenient programming model to application
programmers.
Middleware
In this architecture model, a cache is a store of recently used
data objects that is closer than the objects themselves.
Proxy servers and caches
This term referres to the structuring of software as layers or
modules in a single computer and in terms of services offered
and requested between processes located in the same or
different computers
Software architecture design
It is a running program that
travels from one computer to
another in a network carrying
out a task on someone’s
behalf, such as collecting
information, eventually
returning with the results.
A mobile agent
This is the architecture model
that is most cited when
distributed systems are
discussed.
Client-Server model
It is the form of distribution
that integrates mobile devices
and other devices into a given
network with easy connection,
easy integration, limited
connectivity, etc
Spontaneous networking
Performance issues arising
from the limited processing
and communication capacities
of computers and networks are
considered under the following
subheadings:
Responsiveness, throughput and balancing computational loads.
