swe exam 1 chapters 5, 6, & 8

What are the four system modelling types?

What are the four system modelling types?

1. Context model

2. Behavioral Models

3. Semantic Data Models

4. Object Models

Context models:

used to illustrate the operational context of a system

Behavior models:

used to describe the overall behavior of a system

Semantic data models:

used to describe the logical structure of data processed by the system

What are the two types of behavior models?

Two types:

• data processing models: show how data is processed as it moves thru the system

  • simple & intuitive

  • show end-to-end processing of data

• state machine models: show the systems’ response to events

  • when event occurs, system moves from one state to another

Data dictionaries:

lists of all of the names used in the system models; descriptions of the entities, relationships, and attributes are also included

What are the advantages of data dictionaries?

• support name management and avoid duplication

• store organizational knowledge linking analysis, design, and implementation

What is a type of semantic models?

object models

Object models:

natural ways of reflecting the real-world entities manipulated by the system

Unified modeling language (UML):

a standard representation devised by the developers of widely used object-oriented analysis and design methods.

What are the two UML diagram types?

static and dynamic

List the static UML diagrams:

• Class

• Component

• Deployment

• Object

List the dynamic UML diagrams:

• Activity

• Sequence

• State machine (state transition diagram)

• Use case

Multiple inheritance:

allows object classes to inherit from several super-classes

Multiple inheritance can lead to _______ _______ where attributes/services with the same name in different super-classes have different semantics.

sematic conflicts

CASE workbenches:

a coherent set of tools that is designed to support related software process activities such as analysis, design, or testing

Architerual design:

the design process for identifying the sub-systems making up a system and the framework for sub-system control and communication

What is the output of architectural design?

software architecture

What are architecture and system characteristics?

• performance

• security

• safety

• availability

• maintainability

System organization:

reflects the basic strategy that is used to structure a system

What are the two organizational models?

1. Data repository model

2. Client-server model

Data repository model:

sub-systems must exchange data; shared data is held in a central database or repository and may be accessed by all sub-systems

What are the advantages of the data repository model?

• efficient way to share large amounts of data

• sub-systems need not be concerned with how data is produced; central management

• sharing model is published as the repo schema

What are the disadvantages of the data repository model?

• sub-systems must agree on a repo data model; inevitably a compromise

• data evolution is difficult and expensive

• no scope for specific management policies

• difficult to distribute efficiently

Client-server model:

shows how data and processing is distributed across a range of components

What are the advantages of the client-server model?

• distribution of data is straightforward

• makes effective use of networked systems; may require cheaper hardware

• easy to add new servers or upgrade existing servers

What are the disadvantages of the client-server model?

• no shared data model so sub-systems use different data organization; data interchange may be inefficient

• redundant management in each server

• no central register of names and services which means it may be hard to find out what servers and services are available.;

Sub-system:

a system in its own right whose operation is independent of the services provided by other sub-systems (basically a component: login, payment, etc.)

Module:

a system component that provides services to other components but would NOT normally be considered as a separate system (basically a component of a component)

Modular decomposition:

the structural level where sub-systems are decomposed into modules

What are the two decomposition models?

1. an object model where the system is decomposed into an interacting object

2. A pipeline or data-flow model where the system is decomposed into functional modules which transform inputs into outputs

List the object model advantages (decomposition):

• objects are loosely coupled so their implementation can be modified without affecting other objects

• the objects may reflect real-world entities

• OO implementation languages are widely used

Invoice processing system: Object Model Example

Invoice processing system: Pipeline Example

Control styles:

concerned with the control flow between sub-systems.

“Are we building the product right” refers to:

verification

“Are we building the right product” refers to:

validation

SW inspections refer to ________ verification, while SW testing refers to ________ testing.

static; dynamic

SW Inspections:

• examine source representation to discover anomalies and defects WITHOUT execution of the system

• can check conformance with a specification but NOT with the customer’s real requirements

• CANNOT check non-functional characteristics such as performance, usability, etc.

• should NOT be used to conduct inspections for staff appraisal

SW inspection and testing are _________ and not ___________ verification techniques.

complementary; opposing

Inspection procedure:

• System overview presented to inspection team

• code and associated docs are distributed to inspection team in advance

• inspection takes place and discovered errors are noted

• modifications are made to fix error

• reinspection may or not be needed

• checklist of common errors should be made to guide inspection

Typically six people involved in any inspection:

• 2 code authors

• 2 code inspectors

• 1 reader and scriber

• 1 moderator

Static analyzers are:

SW tools for source text processing

Static analysis:

LINT

Cleanroom SW development philosophy:

defect avoidance rather than defect removal

Cleanroom is based on:

• incremental development

• formal specification

• static verification using correctness arguments

• statistical testing to determine program reliability

Cleanroom process teams:

• certification

• development

• specification

System testing involves:

integrating components to create a system or subsystem

What are the two phases of system testing?

• Integration testing: testing along the way

• Release testing: testing the complete system to deliver as a black-box

What is the difference between glass, white, and black-box testing?

• glass: can see code but not edit

• white: can see and edit code

• black: no access to code

Stress testing:

tests the system beyond maximum design load to test failure behavior

Component testing:

test individual components in isolation

Test case design:

create a set of tests that are effective in validation and defect testing

Test case design approaches:

• Requirements testing

• Partition testing

• Structural testing

Partition testing:

• Input data and output results often fall into different classes where all members of a class are related

• Each of these classes is an equivalence partition or domain where the program behaves in an equal way for each class member

Structural testing is also known as:

white-box testing

Path testing:

• objective is to ensure that each path is executed at least once

• flow graph

Test automation:

• Junit support

• most testing workbenches are open systems because testing needs are organization specific