DISTRIBUTED SYSTEMS MIDTEM
QUESTIONS WITH 100%VERIFIED
ANSWERS
Openness - ✔✔Compatibility with other resources
Interoperability - ✔✔Open distributed systems offer components that can be used by or
integrated into other systems
Portability - ✔✔System should be flexible enough for apps to be compliant with other
distributed systems
Scalability (size) - ✔✔More users and resources may be added without noticeable loss of
performance
Scalability (geographically) - ✔✔Despite distance between users and resources
communication delays are hardly noticed
Scalability (administrative) - ✔✔Easily manageable even if spanning many independent
administrative organisations
3 types of scaling out techniques - ✔✔1. Hiding communication latencies
2. Partitioning and Distribution
3. Replication
Hiding Communication Latencies - ✔✔* 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 - ✔✔Splitting a component into smaller parts and spreading out
across the system
Examples of partitioning and distributing - ✔✔* 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 - ✔✔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 - ✔✔When replication is done near the client
3 types of high performance computing (HPC) - ✔✔1. Cluster computing
2. Grid computing
3. Cloud computing
3 types of pervasive systems - ✔✔1. Ubiquitous computing
2. Mobile computing
3. Sensor networks
QUESTIONS WITH 100%VERIFIED
ANSWERS
Openness - ✔✔Compatibility with other resources
Interoperability - ✔✔Open distributed systems offer components that can be used by or
integrated into other systems
Portability - ✔✔System should be flexible enough for apps to be compliant with other
distributed systems
Scalability (size) - ✔✔More users and resources may be added without noticeable loss of
performance
Scalability (geographically) - ✔✔Despite distance between users and resources
communication delays are hardly noticed
Scalability (administrative) - ✔✔Easily manageable even if spanning many independent
administrative organisations
3 types of scaling out techniques - ✔✔1. Hiding communication latencies
2. Partitioning and Distribution
3. Replication
Hiding Communication Latencies - ✔✔* 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 - ✔✔Splitting a component into smaller parts and spreading out
across the system
Examples of partitioning and distributing - ✔✔* 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 - ✔✔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 - ✔✔When replication is done near the client
3 types of high performance computing (HPC) - ✔✔1. Cluster computing
2. Grid computing
3. Cloud computing
3 types of pervasive systems - ✔✔1. Ubiquitous computing
2. Mobile computing
3. Sensor networks
