What is true about Apache Hadoop MapReduce?

Which of the following techniques woud effectively subvert a properly-implemented proof-of-work distributed blockchain system implementing some sort of cryptocurrency?

One of the most common causes of transient failures, other than temporary network connectivity failures, is

Which one is a key characteristic of publish-subscribe system?

Which of these is an example of code on demand style of code-mobility?

You want a system to have at least 99.5% reliability.  The system is to be implemented using replicated instances of a component, but a single instance of that component has only 90% reliability.  If the system will work as long as at least one of the components is working, no other failures are relevant, and component failures are independent, what is the minimum number of component instances (total, including the first component) that must be in the system?

Which one is a key characteristic of a publish-subscribe system?

Imagine we are using Chord and performing a lookup for key 12. Given this Chord finger table, showing i and succ(p + 2^(i-1)): 1: 9 2: 9 3: 9 4: 14 5: 20 Which node will be selected next for investigation?

One decentralized mutual exclusion approach we discussed involved replicating a resource N times, where access requires a majority vote from m > N/2 coordinators. What is the impact of increasing m if all other parameters were kept the same?

In a RESTful API: