Karteikarten
SCC 204
Karten in diesem Stapel (81)
- 1What are 5 Different development processes? HAWRSWaterfall
Agile
Spiral
Reuse
Hybrid - 25 factors that = Dependability? (Software Design context) ARPSSAvailability
Reliability
Safety
Security
Performance - 3What does Efficiency refer to?Use of processor cycles, memory and power consumption.
- 4Why does efficiency matter?Small systems like embedded systems will have limited memory and much smaller processors. Memory management and Code complexity would need monitoring.
- 5What are the 6 Objectives or software design? RRCERFRobustness
Correctness
Reusability
Efficiency
Reliability
Flexibility - 6What is the design process 1 - 6 High level - low levelArchitectural design
Abstract design
Interface design
Component design
Data structure
Algorithm design - 7Software Architecture design processidentifying the sub-systems that make up the system.
- 8What is Architectural design?framework for control and communication of different sub-systems.
- 9What are stages of a software lifecycle?Requirements
Analysis
Architecture/Design
Code and Unit testing
Subsystem testing
System testing - 10What are 5 Different architectural models?Static Structure
Dynamic Process
Interface
Relationship
distribution - 11What are advantages of explicit architecture?Stakeholder Communication
System Analysis
Large-scale reuse - 12—Box and Line diagram of a systems architecture.
(Conceptual, Lack semantics, add numbers to each sub-system to show order of calls) - 13What is a requirement?Description of what the system under development should do and any constraints under which it must do it.
(What it will do not how it will do it) - 14How do requirements help in stakeholder/customer communication?Acts as a contract between the development team and the customer.
(Written at a level the customer understands) - 15What are some requirements in writing requirements?Gives a general description of context and domain
Scope of the product
SHALL statements what the system will do - 16What are Non-Functional Requirements?Constraints on how the SUD should behave
(Availability, performance, security, usability, and accessibility, reliability)
- still uses SHALL - 17How can Use Cases help with design?A way to structure requirements,
Structure according to stakeholder needs - 18Why are Use Cases useful? (2)Describe scenarios or ample execution scenarios for the SUD, which are easy to understand.
They offer a way to transition into architectural design.
Used to derive test cases. - 19What is in a use case?Actor - someone or something that interacts with the system.
Use case - a sequence of interactions between actors and the system.
Use case model. - 20Sections of a use case description?Name, Scope,
Primary actor, Secondary actor
Summary, Preconditions,
MainSuccess, Alternatives, Exceptions, Postconditions - 21What are some use case principles?Avoid excessive structuring,
Avoid functionally decomposes,
Use cases in project planning
Use cases in testing
Non-functional requirements. - 22What are different levels of granularityCloud
Sea-level
Fish
Bottom of the ocen - 23What are the 3 steps architectural design?System structuring
Control modelling
Modular decomposition - 24What is the idea for System Structuring?Identify key sub-systems and configuration - informed by requirement architectural styles
- 25How do we map requirements to sub-systems?Identify major functions,
Associate the major functions with sub-systems by grouping together similar functions.
Can be decomposed by repeating. - 26What is an element in software architecture?Systems building blocks, the main purpose of the block and what does each element provide.
- 27What is a form in software architecture?How elements are organized in the architecture
How they are composed and characteristics on interactions and relationships - 28What questions does a form answer?How the overall architecture is organized.
How Elements are composed to accomplish the systems key tasks.
How elements are distributed over a network - 29What is Rational in software architecture?Represents the systems designers intent, assumptions and subtle choices, constraints and selected architectural style, design patterns?
- 30What Questions does Rationale answer?Why some elements are used.
Why they are combined in a particular way.
Why the system is distributed in a given manner. - 31What does ADL stand for?Architecture Description Language?
- 32How are sub-system interfaces configured?Interface name (IAccount)
Operations (getBal(:int):float)
Exceptions (accountNoExcep //invalid no)
Service level quality (optional) - 33What can Architectural styles affect system characteristicsPerformance (Fine grain, Large grain)
Security (layered)
Safety (local)
Availability
Maintainability (fine) - 34What advantages and --conflicts may we face when using large grain components?+ Improve performance
- reduces maintainability - 35What advantages and conflicts may we face when using redundant components?+ availability
- security more difficult - 36What conflicts do we face when localizing safety-related features?- Degraded performance
- 37What conflicts do we face when using small grain components?+ reuse
- degrade performance - 38What are Architectural styles?Templates for structuring system architectures.
Stylized description of good design practice (tried and tested) - 39—Repository Style
+ Independent, changes can be propagated
- Single point of failure, inefficiencies in organization communications
- 40—Layered Architecture Style
+ Replacement of entire layers so long as the interface is maintained, authentication
- clean separation is difficult, high -> low interaction is slow -> bad performance
- 41—Client-Server style
+ Servers can be distributed over net, functionality available for all clients
- single point of failure on each service, susceptible to dos or server failure. performance unpredictable.
- 42—2-Tier Thin Client
processing on server-side
- 43—2-Tier fat client
processing on server-side
- 443 Tier advantagesEach of the application architecture layers executes on a separate processor/
Allows better performance than a thin & simpler to manage than a fat.
More salable architecture as demand increases. - 45—Pipeline
+ Easy to understand and supports transformation reuse. Match business processes. Implemented as sequential or concurrent system.
- format has to be agreed upon, each one must parse and process then pass on, increases system overhead.
- 46—Service-Oriented Architecture (waiter example, do not call methods)
+ Access to 3rd party services on demand, useful when you have volatile functionality that is used occasionally, cuts maintenance, individuals no need for prior knowledge
- raises trust issues and privacy issues, difficult to ensure QoS guarantees not for safety critical systems.
- 47—Model-View-Controller
+ Data change independently of its representation & vice versa, Presentation of same data in different ways.
- Involve additional code and code complexity.
- 482 Types of Models of Control?Centralized control
Event-based control - 49What is centralized control?One sub-system has overall responsibility for control and starts and stops other sub-systems
(Call-Return, good for sequential, top down) - 50—Management model
- 51—Call-return model
- 52What is a Manager model within the context of centralized control?Concurrent Systems,
One sub-system controls stopping, starting coordination of other system processes.
Can be implemented as sequential. - 53What is event-based control?Each sub-system responds to external generated events from other sub-systems or environment.
- 54What are two principles of event driven systems?Broadcast models
Interrupt models - 55What is a broadcast model?Action listener, all systems or elements that are observing will handle events.
- 56What is a interrupt models?Real-time systems where interrupts are detected by a handler and passed to other components for processing. Good for timing.
- 57What is modular decomposition?Sub-systems are decomposes into modules
(objects, data-flow, components...) - 58What does UML Stand for?Unified Modeling Language
- 59Key features of object orientation?Objects
Classes
Relationships
Interfaces
Polymorphism
(Inheritance) - 60What does a object have?State
Behavior
Identity - 61what is Association?objects associated with one or more other object
Student <----> Degree Course
many one - 62Example of Aggregation?Table <>---- TableTop, Leg
- 63Example of Composition?Car <>------ spark-plug
- 64Three ways of polymorphism in distinct forms?Method overloading (211 recursive indirect)
Method overriding through inheritance
Method overriding through interfaces - 65What are Stereotypes?Allow for new entities to be derived from existing ones.
<>, <>, < - 66Steps on drawing a sequence diagram1. Identify instances of classes that participate in the sequence
2. Establish the sequence of method calls
3. Draw the instances at top of the page
4. add method calls starting with the top left to show alternative, optional and loops. - 67What is the 1st principle of modeling?The choice of model has a profound influence on how a problem is attacked and a solution is formed.
- 68What is the 2nd principle of modeling?Every model can be expressed at different levels of precision
- 69What is the 3rd principle of modeling?Best modes are connected to reality.
(don't ignore exceptions, incorporate relationships) - 70What is the 4th principle of modeling?No single model is sufficient
- 71What is a view?Represented using a particular type of diagram
- 72—Finite state machine
- 73What are 3 Reasons State patterns are used?Intent - allow an object to alter its behavior when its internal state changes.
Motivation - Object is expected to behave differently depending on which state it is currently in
Applicability - object behavior depends on its state. - 74—State Pattern Structure
(Handles hierarchy naturally, override superstate actions if necessary)
- 75What are three different design patterns?Observer
Singleton
Adapter - 76What are design patterns?Solutions to regular problems
Patterns of problems -> Patterns of solutions
Solution to design not functional - 77Design pattern structureName
Description
Example of use
Description of solution
Discussion of + and - - 78Describe the observer patternAction listener, cars at traffic lights observe light, when change, observers handle the change.
(publish and subscribe relationship) - 79Describe the singleton patternWhen class instantiation is handled only by one class. Not directly.
Increases security, cannot have more than one object managing security.
(Creational) - 80Describe the Adapter PatternGerman Socket <- Adapter <- UK Plug
Adapting to object without changing its source code. - 81—
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- Karteikarten am SCC 204, erstellt von Alex Stout am 09/05/2017.
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