L4 - System Decomposition Flashcards Preview

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Flashcards in L4 - System Decomposition Deck (26):
1

Filter

Processing Step

2

8 Steps of System Design

  1. Design Goal
  2. Subsystem Decomposition
  3. Concurrency
  4. Hardware/Software Mapping
  5. Persistent Data Management
  6. Global Resource Handling
  7. Software Control
  8. Boundary Conditions

3

Closed Architecture (Opaque Layering)

Layer can only call operations from layer below. Buschmann: 'direct addressing' - low coupling: more portable

4

API

Application Programmer's Interface (API) specifies the subsystem interface

5

What is not explicitly shown in Communication Diagrams?

Labels + Roles + Multiplicities (Difference between Communication and Class Diagrams)

6

Open Architecture (Transparent Layering)

Layer can call any operation. Buschmann: 'indirect addressing' - high coupling: higher performance

7

Which architectural style should be used when considering systems with high coupling?

Model View Controller

8

Problem Solving Heuristics

Understanding the problem + Devising a plan + Executing plan + Examining solution

9

Process Flow MVC

  1. View sends update to Controller
  2. Controller updates Model
  3. Model updates View

10

View (MVC)

Subsystem that contains boundary objects (displaying information to user)

11

Cohesion

Dependency and relation among classes. More interaction within their subsystem (high cohesion) = the better.

12

Controller (MVC)

Subsystem between views and models (responsible for interacting with user & change mangement)

13

Pipe

Connection between two processing steps

14

Client-Server Architecture

Client (Input + Front End Processing) + Server (Data Management)

15

'Layer A calls layer B'

Runtime dependency

16

MVC

Model View Controller decouples data access and data presentation.

17

T.H.E. System (Dijkstra)

Selected Layer has no knowledge of higher layers ('directed addressing')

18

'Layer A depends on layer B'

Usage/Compile Time Dependency

19

3-layered Architecture

Application consists of three hierarchically ordered layers.

20

Design Goal

Identify functional and non-functional Design Goals. Stakeholders might have different needs than developers (trade-off)

21

Communication Diagram

Class Diagram + Messages (sequential/conditional/concurrent)

22

Subsystem Decomposition

Reduce the complexity of system while allowing change (high cohesion + low coupling)

23

Coupling

Dependency among subsystems. Low coupling (subsystem interactions) desirable. Calling class should not know anything about internal variables (Principle of information hiding)

24

3-tier Architecture

Closed Architecture + 3 Layers on 3 separate hardware nodes (web browser + web server + database)

25

Service

Group of externally visible operations provided by a subsystem

26

Model (MVC)

Subsystem that contains entity objects (responsible for application domain knowledge)