W9 L3 - System Architecture

Question 1

What are the 3 tiers of system architecture

Answer 1

Presentation tier - the most top level of the application is the user interface. The main function of the interface is to translate tasks and results to something the user can understand.

Logic tier - this layer coordinates the application, process commands, makes logical decisions and evaluations and performs calculations. It also moves and processes data between the two surrounding layers

Data tier - Information is stored and retrieved from a database or file system. The information is passed back to the logic tier for processing, then eventually back to the user.

Question 2

What are/is the considerations/framework of a system architecture for an enterprise

Answer 2

e a framework to help define; e.g., TOGAF: The Open Group Architect Framework

• Business: business strategy, governance, organisation, key business processes
• Applications: deployment plan, interactions between applications, relationships to business processes
• Data: structure of all data assets and the management thereof
• Technical/technology: hardware, software, and network infrastructure needed to support core applications

Question 3

What is IS architectures

Answer 3

“…describes the system’s hardware, software, and network environment.”
“The architecture design flows primarily from the non-functional requirements, such as operational, performance, security, cultural, and political requirements.”

General goals
“…determine how the software components of the information system will be assigned to the hardware devices of the system.”
Technical, integration, portability, maintainability, speed, capacity, availability, reliability, access control, encryption, international, legal, within budget.

Question 4

Describe the client/server model

Answer 4

• It is a prototype on a smaller scale before you implement on an enterprise scale.
• A “model” (often called client/server architecture)
• A logical separation of tasks/workload
• Client: putting in the task/process/function request
  - requestor of work.
  - An end-user uses this
  - There are lots of these
  e.g. posting on piazza - initiated by an actor
  Server:
  - services requests (does the work)
  - Few but grunty - needs to be able to take multiple
  requests. Server needs to be able to deliver
  achievable tasks

Question 5

What is a logical tier

Answer 5

May be physically on client or server

• Thick vs thin clients
• 1-tier vs n-tier servers/ systems
• Logical Tiers. The interacting software components of distributed enterprise applications can be viewed as residing in a number of logical tiers. These tiers represent the logical and physical independence of software components based on the nature of the services they provide.

Question 6

What are the differences between thick and thin clients

Answer 6

Thin Client
Definition: Software that relies on a remote server such as a cloud platform for its features.
Offline: Functions mostly don’t work
Local Resources: Generally consumes few local resources such as disk, computing power and memory.
Network Latency: Functionality may depend on a fast network connection
Data: Data is typically stored on servers.

Thick Client
Definition: Software that runs at least some features directly on your device.
Offline: Functions mostly work
Local Resources: Generally consumes more local resources
Network Latency: Functionality may work without a connection or with a slow connection
Data: Data may be stored locally