Module 2a - Architecture

Question 1

What is a component

Answer 1

A modular unit with well-defined interfaces.

Is isolatable and does not rely on the existence of other components to function

Question 2

What is a connector

Answer 2

A mechanism that mediates communication, coordination, or cooperation among components

Question 3

What is “software architecture”

Answer 3

The way that software components are organized

Question 4

What is “system architecture”

Answer 4

Instantiation of software architecture in which software components are placed in real machines

Question 5

What is an “Autonomic System”

Answer 5

A system which adapts to its environment by monitoring its own behaviour and reacts accordingly

Question 6

What are the 4 typical architectural styles which distributed software systems conform to?

Answer 6

• Layered
• Object Based
• Data Centered
• Event Based

Question 7

What is Layered architecture?

Answer 7

Control flows from layer to layer: Requests flow down the hierarchy and responses flow up the hierarchy.

Question 8

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<p>How do primitive client-server patterns work?</p>

Answer 8

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<p>A component (client) requests a service from another component (server) and waits for a response (unless it is a asynchronous request)</p>

Question 9

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<p>What are the 3 fundamental layers that enterprise systems typically organized into?</p>

Answer 9

User interface (Client Application / Front End)
Application Server (Back End)
Database Server

Question 10

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<p>What is Vertical distribution?</p>

Answer 10

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<p>When logical layers of a system are organized as separate physical tiers on the same machine</p>

Question 11

What is Horizontal distribution?

Answer 11

When one logical layer is split across multiple machines. Also known as sharding

Question 12

What is Object-based Architecture?

Answer 12

When components are organized in as objects

Question 13

What is Data-centered architecture?

Answer 13

Components communicate by accessing a shared data repository such as a database, storage system, or file system

Question 14

What is Event-based architecture?

Answer 14

Components communicate by propagating events. Publish/Subscribe systems are used for communicating asynchronous events

Question 15

What are peer-to-peer (P2P) systems?

Answer 15

They rely on horizontal distribution and are designed to deal with churn (machines joining and leaving).

Processes are organized in an overlay network that defines a set of communication channels

Question 16

What is a self-managing system

Answer 16

They are systems which are constructed using a feedback control loop that monitors system behaviours and adjusts the systems internal operation based on this

Question 17

BitTorrent combines client-server and P2P architectures. How does it work?

Answer 17

Client nodes obtain tracker information from a server and then exchange data with peer nodes.

Web server makes API call to File Server which makes API call to tracker service which tracks the state of the network nodes (P2P nodes)