Distributed Systems Midterm UPDATED
ACTUAL Exam Questions and CORRECT
Answers
Openness - CORRECT ANSWER - Compatibility with other resources
Interoperability - CORRECT ANSWER - Open distributed systems offer components that
can be used by or integrated into other systems
Portability - CORRECT ANSWER - System should be flexible enough for apps to be
compliant with other distributed systems
Scalability (size) - CORRECT ANSWER - More users and resources may be added
without noticeable loss of performance
Scalability (geographically) - CORRECT ANSWER - Despite distance between users and
resources communication delays are hardly noticed
Scalability (administrative) - CORRECT ANSWER - Easily manageable even if spanning
many independent administrative organisations
3 types of scaling out techniques - CORRECT ANSWER - 1. Hiding communication
latencies
2. Partitioning and Distribution
3. Replication
Hiding Communication Latencies - CORRECT ANSWER - * The goal is to reduce the
wait time for the remote service requests of clients
* Requires asynchronous communication
* Fails for interactive services where each step requires approval from the server
, ** Work around is to outsource the job of making checks to the client itself and limiting the
communication required by the server to a minimum
Partitioning and distributing - CORRECT ANSWER - Splitting a component into smaller
parts and spreading out across the system
Examples of partitioning and distributing - CORRECT ANSWER - * Internet Domain
Name System
* Document handling over the internet
** The web itself is physically partitioned and distributed across many servers, each handling a
number of docs
** The name of the server that handles a document is encoded into the document's URL
Replication - CORRECT ANSWER - Increases availability and helps to balance the load
between components leading to better performance, helps with hiding communication latency by
providing copies(replicas)
* Drawback is that resources can be inconsistent, meaning that the browser returns a cached
document of which validity has not been checked in the last few minutes
Bad for stock exchanges, ebay, etc.
Caching - CORRECT ANSWER - When replication is done near the client
3 types of high performance computing (HPC) - CORRECT ANSWER - 1. Cluster
computing
2. Grid computing
3. Cloud computing
3 types of pervasive systems - CORRECT ANSWER - 1. Ubiquitous computing
2. Mobile computing
3. Sensor networks
ACTUAL Exam Questions and CORRECT
Answers
Openness - CORRECT ANSWER - Compatibility with other resources
Interoperability - CORRECT ANSWER - Open distributed systems offer components that
can be used by or integrated into other systems
Portability - CORRECT ANSWER - System should be flexible enough for apps to be
compliant with other distributed systems
Scalability (size) - CORRECT ANSWER - More users and resources may be added
without noticeable loss of performance
Scalability (geographically) - CORRECT ANSWER - Despite distance between users and
resources communication delays are hardly noticed
Scalability (administrative) - CORRECT ANSWER - Easily manageable even if spanning
many independent administrative organisations
3 types of scaling out techniques - CORRECT ANSWER - 1. Hiding communication
latencies
2. Partitioning and Distribution
3. Replication
Hiding Communication Latencies - CORRECT ANSWER - * The goal is to reduce the
wait time for the remote service requests of clients
* Requires asynchronous communication
* Fails for interactive services where each step requires approval from the server
, ** Work around is to outsource the job of making checks to the client itself and limiting the
communication required by the server to a minimum
Partitioning and distributing - CORRECT ANSWER - Splitting a component into smaller
parts and spreading out across the system
Examples of partitioning and distributing - CORRECT ANSWER - * Internet Domain
Name System
* Document handling over the internet
** The web itself is physically partitioned and distributed across many servers, each handling a
number of docs
** The name of the server that handles a document is encoded into the document's URL
Replication - CORRECT ANSWER - Increases availability and helps to balance the load
between components leading to better performance, helps with hiding communication latency by
providing copies(replicas)
* Drawback is that resources can be inconsistent, meaning that the browser returns a cached
document of which validity has not been checked in the last few minutes
Bad for stock exchanges, ebay, etc.
Caching - CORRECT ANSWER - When replication is done near the client
3 types of high performance computing (HPC) - CORRECT ANSWER - 1. Cluster
computing
2. Grid computing
3. Cloud computing
3 types of pervasive systems - CORRECT ANSWER - 1. Ubiquitous computing
2. Mobile computing
3. Sensor networks
