DISTRIBUTED SYSTEMS MIDTERM
EXAM UPDATED ACTUAL Exam
Questions and CORRECT Answers
Software architecture - CORRECT ANSWER - tell us how the software components are
organized and how they interact
How can we separate applications from the underlying platforms? - CORRECT
ANSWER - - use a middleware layer which provides distribution transparency
System architecture - CORRECT ANSWER - - the final instantiation of a software
architecture where it goes on real machines
- this can include centralized or decentralized architecture
component - CORRECT ANSWER - a modular unit with well defined interfaces and are
replaceable, while the system continues to operate
4 architectural styles - CORRECT ANSWER - - layered architecture (components are
organized in a heirarchy making calls down the layers)
- object based architecture
- resource-centered architecture
- event based architecture
communication protocol stacks - CORRECT ANSWER - each layer implements a
communication service with the layer offering an interface for functions that can be called and
allowing data to be sent to one or several targets
- communication protocol describes the rules that parties must follow to exchange info
Transmission Control Protocol (TCP) - CORRECT ANSWER - - provides reliable,
ordered, and error-checked delivery of a stream of packets on the internet
, - AF_NET and SOCK_STREAM are used to specify that the TCP protocol should be used to
communicate between two parties
Three logical levels in Application layering - CORRECT ANSWER - * application-
interface level
* processing level
* data level (data is persistent and responsible for keeping data consistent across apps)
Object-based and Service-oriented Architectures - CORRECT ANSWER - - each object is
a component and components are connected through procedure calls
- benefits: encapsulate data (called an objects state) and the operations (or methods) into a single
entity
- when a client binds to a distributed object the implementation of the object's interface, called a
proxy, is loaded into the client's address space
proxy - CORRECT ANSWER - - the implementation of an object interface
- it mashal's method invocations into messages and unmarshals reply messages to return the
result of the method invocation to the client
- incoming invocations from the client are passed to a server stub called a skeleton, which
unmarshals the request to make method invocations at the object interface
remote objects - CORRECT ANSWER - - a distributed object where the state is not
distributed (its on a single machine)
- only the interfaces implemented by the object are available on other machines
In service-oriented architecture (SOA) a distributed app is a composition of many _______ -
CORRECT ANSWER - - different services that may not all belong to the same
administrative org
- thus SOA is based on service composition
EXAM UPDATED ACTUAL Exam
Questions and CORRECT Answers
Software architecture - CORRECT ANSWER - tell us how the software components are
organized and how they interact
How can we separate applications from the underlying platforms? - CORRECT
ANSWER - - use a middleware layer which provides distribution transparency
System architecture - CORRECT ANSWER - - the final instantiation of a software
architecture where it goes on real machines
- this can include centralized or decentralized architecture
component - CORRECT ANSWER - a modular unit with well defined interfaces and are
replaceable, while the system continues to operate
4 architectural styles - CORRECT ANSWER - - layered architecture (components are
organized in a heirarchy making calls down the layers)
- object based architecture
- resource-centered architecture
- event based architecture
communication protocol stacks - CORRECT ANSWER - each layer implements a
communication service with the layer offering an interface for functions that can be called and
allowing data to be sent to one or several targets
- communication protocol describes the rules that parties must follow to exchange info
Transmission Control Protocol (TCP) - CORRECT ANSWER - - provides reliable,
ordered, and error-checked delivery of a stream of packets on the internet
, - AF_NET and SOCK_STREAM are used to specify that the TCP protocol should be used to
communicate between two parties
Three logical levels in Application layering - CORRECT ANSWER - * application-
interface level
* processing level
* data level (data is persistent and responsible for keeping data consistent across apps)
Object-based and Service-oriented Architectures - CORRECT ANSWER - - each object is
a component and components are connected through procedure calls
- benefits: encapsulate data (called an objects state) and the operations (or methods) into a single
entity
- when a client binds to a distributed object the implementation of the object's interface, called a
proxy, is loaded into the client's address space
proxy - CORRECT ANSWER - - the implementation of an object interface
- it mashal's method invocations into messages and unmarshals reply messages to return the
result of the method invocation to the client
- incoming invocations from the client are passed to a server stub called a skeleton, which
unmarshals the request to make method invocations at the object interface
remote objects - CORRECT ANSWER - - a distributed object where the state is not
distributed (its on a single machine)
- only the interfaces implemented by the object are available on other machines
In service-oriented architecture (SOA) a distributed app is a composition of many _______ -
CORRECT ANSWER - - different services that may not all belong to the same
administrative org
- thus SOA is based on service composition
