F1 Flashcards
What’s the characteristics of a distributed system?
- Decentralisation
- Fault tolerance
- Scalability
- Transparency
What’s decentralisation?
The computation will be decentralized into multiple nodes in the system
Whats Fault tolerance?
There could be failure, but in case of failure you should be able to process your request, you will figure out how to keep processing even in face of failure.
What’s Scalability?
You can add more and more nodes to the system, more scalable than a single system
What’s Transparency?
You don’t want to interact with several machines. The middle layer provides transparency. Reduce complexity of the system for the end user and developer.
What are some challenges regarding distributed systems?
- Communication delays
- Consistency and Replication
- Fault detection and recovery
- Security concerns
What happens with partial failure in a single system compared to DS?
Partial failure affects the whole system for a single system. In DS, more machines means we can keep processing even with a partial failure.
What are some benefits with DS?
-Better performance (more resources)
-Resource sharing, reduced cost
-No choice ?, need for scalability
-Fault tolerance and recovery
-Better throughput, gets data from nearest data center
What cloud computing?
A model for delivering and consuming computing resources as a service over the internet
IaaS, PaaS, SaaS
What’s a characteristic of overlay network?
Each node communicates only with other nodes in the system and it’s neighbors.
What are the two overlay types?
Structured overlay: You have a specific list of nodes with whom you can talk (topology)
Unstructured overlay: Each node has references to randomly selected nodes from the system.
DEMAND: There should be a link from one node to any other node in the system
What do we mean when we say a system is coherent?
The collection of nodes as a whole operates the same, no matter where. when or how the interaction between a user and the system occurs
What’s middleware?
The OS of the DS, it’s commonly used components and functions that need not to be implemented by apps separately. This provides reliability and hides complexity of the actual OS and hardware
Why do we share resources in DS?
To make it more cost effective
What are some examples of shared resource DS?
-Cloud-based shared storage and files
-P2P assisted multimedia streaming
-Shared mail services
-Shared web hosting
What’s distributed transparency?
To hide the fact that processes and resources are physically distributed across multiple computers
