Distributed Systems Test 1 Questions
and Answers
What is a distributed system? - One in which hardware or software components
located at networked computers communicate and coordinate their actions only by
passing messages
Characteristics/Key Challenges of Distributed Systems - 1.Heterogeneity - many
types of hardware and software; handled by middleware and mobile code
2.Openness - seamless extension, easy to expand; requires interfaces,
communication mechanisms and standards
3.Security - CIA model
4.Scalability - add resources within appropriate costs
5.Failure Handing - Failures should be partial, not take down the whole system
6.Concurrency - independent processes run simultaneously; resources must be
managed
7.Transparency - system must be perceived as whole
8.Quality of Service - Reliable, secure, good performance; deadlines
Methods of Failure Handling - Detect a failure
Mask the failure
Tolerate the failure
Recover from the failure
Redundancy
Types of Transparency - Access - remote and local access use same commands
Location - no physical address knowledge requirements
, Concurrency - no interference between running processes
Replication - multiple instances of resource used without user knowledge of
existence
Failure - faults must be concealed so processes and applications can continue to
run
Mobility - resources and clients in a system are able to move
Performance - system can reconfigure based on loads
Scale - system can increase in size without change to structure or applications
Want for distributed systems - Sharing of resources allows for significantly higher
power than any individual computer. Allows performing of tasks that wouldn't
happen otherwise. Allows communications and collaborations to exist that
wouldn't otherwise
Message Passing - a relationship between objects permitting communication;
transmission of information
Resource Sharing - Allowing multiple devices and processes access to available
resources in a system. The key goal of distributed systems
No Global Clock - There is no perfect clock synchronization in a distributed
system. Clocks can drift, so no part of a system can know the exact time of any
other part of the system
Trends in Distributed Systems - Pervasive Networking - Collections of connected
networks
Ubiquitous computing - Computing embedded into everyday objects
Mobile Computing - Being able to perform tasks on the go
Multimedia Services - media access and streaming
and Answers
What is a distributed system? - One in which hardware or software components
located at networked computers communicate and coordinate their actions only by
passing messages
Characteristics/Key Challenges of Distributed Systems - 1.Heterogeneity - many
types of hardware and software; handled by middleware and mobile code
2.Openness - seamless extension, easy to expand; requires interfaces,
communication mechanisms and standards
3.Security - CIA model
4.Scalability - add resources within appropriate costs
5.Failure Handing - Failures should be partial, not take down the whole system
6.Concurrency - independent processes run simultaneously; resources must be
managed
7.Transparency - system must be perceived as whole
8.Quality of Service - Reliable, secure, good performance; deadlines
Methods of Failure Handling - Detect a failure
Mask the failure
Tolerate the failure
Recover from the failure
Redundancy
Types of Transparency - Access - remote and local access use same commands
Location - no physical address knowledge requirements
, Concurrency - no interference between running processes
Replication - multiple instances of resource used without user knowledge of
existence
Failure - faults must be concealed so processes and applications can continue to
run
Mobility - resources and clients in a system are able to move
Performance - system can reconfigure based on loads
Scale - system can increase in size without change to structure or applications
Want for distributed systems - Sharing of resources allows for significantly higher
power than any individual computer. Allows performing of tasks that wouldn't
happen otherwise. Allows communications and collaborations to exist that
wouldn't otherwise
Message Passing - a relationship between objects permitting communication;
transmission of information
Resource Sharing - Allowing multiple devices and processes access to available
resources in a system. The key goal of distributed systems
No Global Clock - There is no perfect clock synchronization in a distributed
system. Clocks can drift, so no part of a system can know the exact time of any
other part of the system
Trends in Distributed Systems - Pervasive Networking - Collections of connected
networks
Ubiquitous computing - Computing embedded into everyday objects
Mobile Computing - Being able to perform tasks on the go
Multimedia Services - media access and streaming
