Distributed Systems (ch.1) UPDATED
ACTUAL Exam Questions and CORRECT
Answers
A distributed system is a collection of autonomous computing elements that appears to its users
as a single coherent system. - CORRECT ANSWER -T
A distributed system is a collection of computing elements (hardware devices or software
processes) each being not being able to behave independently of each other. - CORRECT
ANSWER - F (being able to behave independently of each other)
Users of a distributed system (be they people or applications) believe they are dealing with
multiple systems. - CORRECT ANSWER - F (single coherent system)
We can assume that there is something like a global clock across a distributed system. -
CORRECT ANSWER - F (Each node will have its own notion of time)
Since each node is independent, we need group management and authentication. - CORRECT
ANSWER -T
In closed groups, any node can join the distributed system, effectively meaning that it can send
messages to any other node in the system. - CORRECT ANSWER - F (open groups)
In closed groups, only the members of a group can communicate with each other. - CORRECT
ANSWER -T
In open groups a separate mechanism is needed to let a node join or leave that group. -
CORRECT ANSWER - F (closed groups)
A distributed system is often organized as an overlay network. - CORRECT ANSWER -T
,In overlay networks, a node is typically a software process equipped with a list of other
processes it can directly send messages to. - CORRECT ANSWER -T
An overlay network can be not connected sometimes. - CORRECT ANSWER - F (should
always be connected)
In an unstructured overlay, each node has a well-defined set of neighbors with whom it can
communicate. - CORRECT ANSWER - F (structured overlay)
Tree and logical rings are examples of structured overlay networks. - CORRECT
ANSWER -T
In an unstructured overlay network, each node has several references to randomly selected other
nodes. - CORRECT ANSWER -T
Achieving a single-system view is a must in distributed systems. - CORRECT ANSWER -
F (a distributed systems appears to be coherent)
A distributed system is coherent if it behaves according to the expectations of its users. -
CORRECT ANSWER -T
In a distributed system the collection of nodes operates differently, depending on where, when,
and how interaction between a user and the system takes place. - CORRECT ANSWER -F
(a single coherent system ==> thus operates the same...)
Hiding partial failures and their recovery is often very difficult and in general impossible. -
CORRECT ANSWER -T
Middleware is the same to a distributed system as what an operating system is to a computer. -
CORRECT ANSWER -T
, The middleware layer resides below the application layer and above the operating system
offering the same interface to applications no matter what machine or what operating system the
application is running on. - CORRECT ANSWER -T
o Facilities for inter-application communication.
o Security services.
o Accounting services.
o Masking of and recovery from failures.
The above are services that are offered offered by the middleware that can be found in most
operating systems - CORRECT ANSWER -T
There are no differences between middleware and operating systems. - CORRECT
ANSWER - F (main difference is that middleware services are offered in are offered in a
networked environment)
Typical middleware services also include:
o Communication
o Transactions:
o Service composition
o Reliability. - CORRECT ANSWER -T
Remote Procedure Calls (RPCs) is an example of communication services offered by the
middleware. - CORRECT ANSWER -T
It is acceptable that a transaction can be only executed partly since distributed systems only
APPEAR to be a single coherent systems and executing transactions is a service offered by
distributed systems. - CORRECT ANSWER - F (transactions must be executed in an all-
or-nothing fashion)
ACTUAL Exam Questions and CORRECT
Answers
A distributed system is a collection of autonomous computing elements that appears to its users
as a single coherent system. - CORRECT ANSWER -T
A distributed system is a collection of computing elements (hardware devices or software
processes) each being not being able to behave independently of each other. - CORRECT
ANSWER - F (being able to behave independently of each other)
Users of a distributed system (be they people or applications) believe they are dealing with
multiple systems. - CORRECT ANSWER - F (single coherent system)
We can assume that there is something like a global clock across a distributed system. -
CORRECT ANSWER - F (Each node will have its own notion of time)
Since each node is independent, we need group management and authentication. - CORRECT
ANSWER -T
In closed groups, any node can join the distributed system, effectively meaning that it can send
messages to any other node in the system. - CORRECT ANSWER - F (open groups)
In closed groups, only the members of a group can communicate with each other. - CORRECT
ANSWER -T
In open groups a separate mechanism is needed to let a node join or leave that group. -
CORRECT ANSWER - F (closed groups)
A distributed system is often organized as an overlay network. - CORRECT ANSWER -T
,In overlay networks, a node is typically a software process equipped with a list of other
processes it can directly send messages to. - CORRECT ANSWER -T
An overlay network can be not connected sometimes. - CORRECT ANSWER - F (should
always be connected)
In an unstructured overlay, each node has a well-defined set of neighbors with whom it can
communicate. - CORRECT ANSWER - F (structured overlay)
Tree and logical rings are examples of structured overlay networks. - CORRECT
ANSWER -T
In an unstructured overlay network, each node has several references to randomly selected other
nodes. - CORRECT ANSWER -T
Achieving a single-system view is a must in distributed systems. - CORRECT ANSWER -
F (a distributed systems appears to be coherent)
A distributed system is coherent if it behaves according to the expectations of its users. -
CORRECT ANSWER -T
In a distributed system the collection of nodes operates differently, depending on where, when,
and how interaction between a user and the system takes place. - CORRECT ANSWER -F
(a single coherent system ==> thus operates the same...)
Hiding partial failures and their recovery is often very difficult and in general impossible. -
CORRECT ANSWER -T
Middleware is the same to a distributed system as what an operating system is to a computer. -
CORRECT ANSWER -T
, The middleware layer resides below the application layer and above the operating system
offering the same interface to applications no matter what machine or what operating system the
application is running on. - CORRECT ANSWER -T
o Facilities for inter-application communication.
o Security services.
o Accounting services.
o Masking of and recovery from failures.
The above are services that are offered offered by the middleware that can be found in most
operating systems - CORRECT ANSWER -T
There are no differences between middleware and operating systems. - CORRECT
ANSWER - F (main difference is that middleware services are offered in are offered in a
networked environment)
Typical middleware services also include:
o Communication
o Transactions:
o Service composition
o Reliability. - CORRECT ANSWER -T
Remote Procedure Calls (RPCs) is an example of communication services offered by the
middleware. - CORRECT ANSWER -T
It is acceptable that a transaction can be only executed partly since distributed systems only
APPEAR to be a single coherent systems and executing transactions is a service offered by
distributed systems. - CORRECT ANSWER - F (transactions must be executed in an all-
or-nothing fashion)
