notes…instruct.uwo.ca/engin-sc/se352b/notes/hg-se352lect-w01...se352-w03 19-jan-06 (c) hamada...

SE352-W03 19-Jan-06

(c) Hamada Ghenniwa, ECE, UWO 1

Fri., Jan. 20, 2006 SE352b, ECE,UWO, Hamada Ghenniwa 1

SE352b Software Engineering SE352b Software Engineering Design ToolsDesign Tools

W1: Software Engineering Tools Environment


Notes…Notes…

SE352b Web page:http://instruct.uwo.ca/engin-sc/se352b/

SE352-W03 19-Jan-06



SE352b: RoadmapSE352b: Roadmap

CASE Tools: Introduction

System Programming Tools

Programming Paradigms

Database Technology

Middleware and Connectivity Tools

Web Development Tools

Software Tools: Special Topics


ReferencesReferencesSoftware Engineering: A Practitioner's Approach, 6th Ed, Roger Pressman, McGraw-Hill, 2005

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Software Engineering EnvironmentSoftware Engineering Environment

a “Quality” Focus

Process Model

Methods

Tools

A Layered Approach

a “Quality” Focus

Process Model

Methods

Tools

SE352 FocusSE352 Focus


ComputerComputer--Aided Software Engineering (CASE)Aided Software Engineering (CASE)

A software to support software development and evolution processes

Activity automationGraphical editors for system model development

Graphical UI builder for user interface construction

Data dictionary to manage design entities

Debuggers to support program fault finding

Automated translators to generate new versions of a program

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Why Tools!Why Tools!Sometimes, tools are strictly necessary to support SE activity

e.g., programming languages and their compilers/interpreters

Other times, tools just help in making some jobs easier or more efficiente.g., design and text editors

The more complex the software development becamethe more tools were developed to support it and the more sophisticatedthose tools became

integrating these tools becomes an important issueConsider debugging, editing (remove errors), re-compiling, and re-linking programs


Automated Process SupportAutomated Process Support... the tools address each important step in the software engineering process ...

... the tools

increase insight thereby improving quality

reduce labor-work, thereby improving productivity, and

enhance control, thereby leading to on-time projects ...

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COCOMO:COCOMO:Multiplier Effect of Multiplier Effect of Using Software ToolsUsing Software Tools

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1 2 3 4Requirements andArchitecture design

Detaileddesign

Code andunit test

Integrationand test

Effo

rt m

ult

iplie

rVery low

LowLow

Nominal

High

Very highVery high


CASE Technology:CASE Technology:Not a Silver BulletNot a Silver Bullet

CASE technology

has led to significant improvements in the software process

HoweverHoweverSoftware engineering require

creative thought

this is not readily automatable

team activity

for large projects, much time is spent in team interactions

CASE technology does not (to some extend) guarantee them!

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CASE ClassificationCASE Classification

To help understand the different types of CASE tools

their support for process activities

Several ClassificationsFunctional perspective

Tools are classified according to their specific function

Process perspectiveTools are classified according to process activities that are supported

Integration perspectiveTools are classified according to their organization into integrated units


Functional Tool Classification: ExamplesFunctional Tool Classification: ExamplesTool type ExamplesPlanning tools PERT tools, estimation tools,

spreadsheetsEditing tools Text editors, diagram editors, word

processorsChange management tools Requirements traceability tools, change

control systemsConfiguration management tools Version management systems, system

building toolsPrototyping tools Very high-level languages,

user interface generatorsMethod-support tools Design editors, data dictionaries, code

generatorsLanguage-processing tools Compilers, interpretersProgram analysis tools Cross reference generators, static

analysers, dynamic analysersTesting tools Test data generators, file comparatorsDebugging tools Interactive debugging systemsDocumentation tools Page layout programs, image editorsRe-engineering tools Cross-reference systems, program re-

structuring systems

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Process-based Classification

Reengineering tools

Testing tools

Debugging tools

Program analysis tools

Language-processingtools

Method support tools

Prototyping tools

Configurationmanagement tools

Change management tools

Documentation tools

Editing tools

Planning tools

Specification Design Implementation Verificationand

Validation


CASE IntegrationCASE Integration

ToolsSupport individual process tasks

e.g., design consistency checking, text editing, etc.

WorkbenchesSupport a process phase

specification or design, normally include a number of integrated tools

EnvironmentsSupport all or a substantial part of an entire software process

Normally include several integrated workbenches

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Tools, Workbenches, Environments: ExamplesTools, Workbenches, Environments: Examples

Single-methodworkbenches

General-purposeworkbenches

Multi-methodworkbenches

Language-specificworkbenches

Programming TestingAnalysis anddesign

Integratedenvironments

Process-centredenvironments

FilecomparatorsCompilersEditors

EnvironmentsWorkbenchesTools

CASEtechnology


More ClassificationsMore Classifications

Development tools vs. end-product toolsSupport the developmentbut don’t become part of the product

e.g., project management tools, debugger, etc.become part of the product

e.g., window managers, which provides run-time lib For HCI

Environment/Language dependencyStatic vs. Dynamic toolsVendor

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Integrated CASE EnvironmentIntegrated CASE Environment

... “Ideally”, CASE combines a set of software development tools that are integrated with a database

to form an II--CASECASE environment...


CASE Environment ModelCASE Environment Model(Pressman)(Pressman)

The ChallengePutting them Together

CASE ToolsCASE Tools

CASE ToolsCASE Tools

Integration FrameworkIntegration Framework

Portability ServicesPortability Services

Hardware Platform

Operating System

Environment Architecture

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An Integration FrameworkAn Integration Framework

Tools Management ServicesTools Management Services

CASEtool

Object Management LayerObject Management Layerintegration servicesconfiguration management services

Shared Repository LayerShared Repository LayerCASE databaseaccess control functions

Tools LayerTools Layer

Use

r Int

erfa

c e L

ayer

Use

r Int

erfa

c e L

ayer

inte

r face

tool

kit

pres

enta

tion

prot

ocol


An Integration FrameworkAn Integration Framework(Cont.)(Cont.)

CASE tools

Tools layertools management services - control behavior of tools inside environment

Object management layer (OML)performs the configuration management function, working with the CASE repository OML provides integration services

Shared repository layerCASE database and access control functions enabling the OML to interact with the database

User interface layercontains software for UI management and library of display objects common presentation protocol - guidelines that give all CASE tools the same look and feel (icons, mouse behavior, menu names, object names)

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The Ideal IThe Ideal I--CASE Environment CASE Environment business systems planning

project management

support

integration &testing

re–engineering

prototyping/simulation toolsCASE

Databaseprogramming

framework

analysis and design






Database Technology




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The SE352 StoryThe SE352 Story

Systems ProgrammingTools


Systems ProgramsSystems Programs

software that is usually supplied with the computer hardware to facilitate the process of software development on the supplied hardware

usually machine dependentin an integrated hardware-software environment

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Executable BinaryCode

TranslatorsTranslators

a systems program that translates a symbolic source program into a target machine program

Source Procedure A

Source Procedure B

Source Procedure C

TranslatoTranslator

Interpreter: It simultaneously translates translates and executesand executes a symbolic source machine program

Compiler: It translates a high-level symbolic program in text format into rere--locatablelocatable object object format

ObjectModule A

ObjectModule C

ObjectModule B


Object Module: StructureObject Module: Structure1. contains the name of the module, other linking

informatione.g., the lengths of the various parts of the module, and sometimes the assembly date

2. a list of the symbols (and their values) defined in the module that other modules may reference

3. contains a list of the symbols that are used in the module and defined in other modules,

along with a list of which machine instructions use which symbols

End of module

Identification

Entry point table

Relocation Dictionary

Machine instructionsAnd constants

External Reference table

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Object Module: StructureObject Module: Structure

4. Contains the assembled code and constantsthe only part to be loaded into memory and executed

5. the relocation dictionary

6. an end-of-module indicationsometimes a checksum to catch errors

End of module

Identification

Entry point table

Relocation Dictionary

Machine instructions

And constants

External Reference table


Linker & LoaderLinker & Loader

Source Procedure A

Source Procedure B

Source Procedure C

TranslatoTranslator

ObjectModule A

ObjectModule C

ObjectModule B

Linker &Linker &LoaderLoader

ExecutableBinaryCode

CALL B

MOVE P TO X

BRANCH TO 200

Object module A

CALL D

MOVE R TO X

Object module C

BRANCH TO 200

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Linker & LoaderLinker & Loader

The linker’s function To collects modules translated separately and glue them together to run as a unit called an executable binary program

On MSMS--DOS, Windows and NTDOS, Windows and NTobject modules have extension .obj

the executable binary programs have extension .exe

On UNIXUNIX, object modules have extension .o

executable binary programs have no extension


The Computation Machine: The Computation Machine: Von Neumann ModelVon Neumann Model

PrimaryMemoryI/O Devices

CPU

SecondaryMemory

PrimaryMemoryI/O Devices

CPU

SecondaryMemory

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CPU

Inside the CPU: GenericInside the CPU: Generic

0100

264

MOVE P TO XBRANCH TO 200

PrimaryMemory

PC

ExecutionUnit

Register Set

R0

R15

Clock

Clock Ticks

CPU

Data

Address


Linking & Loading : TasksLinking & Loading : TasksAt the start of pass one of the process,

the instruction location counter is set to 0. This assumes that the object module will be located at (virtual) address 0 during execution

Source Procedure A

Source Procedure B

Source Procedure C

Translator

ObjectModule A

ObjectModule C

ObjectModule B

CALL B

MOVE P TO X

BRANCH TO 200

Object module A400

300

200

100

0

CALL D

MOVE R TO X

Object module C

BRANCH TO 200

500

400

300

200

100

0

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Linking & Loading: TasksLinking & Loading: Tasks

To run the program, The loader brings the object modules into main memory

to form the image of the executable binary programIf there is not enough memory to form the image, a disk file can be used

The objective is tomake an exact image of the executable program’s virtual address space inside the linker

position all the object modules at their correct locations


ExampleExample

600

500

400

300

200

100

0

CALL C

MOVE Q TO X

BRANCH TO 300

Object module B

MOVE S TO X

BRANCH TO 200

300

200

100

0

Object module D1900

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

800

700600

500

400

300

200

100

CALL B

MOVE P TO X

BRANCH TO 200

Object module A400

300

200

100

0

CALL D

MOVE R TO X

Object module C

BRANCH TO 200

500

400

300

200

100

0

Although the program is loaded into the image of the executable binary file, it is not yet ready for execution

ObjectModule D

ObjectModule C

ObjectModule B

ObjectModule A

1900

MOVES S TO X

BRANCH TO 200

CALL D

MOVE R TO X

BRANCH TO 200

CALL C

MOVE Q TO X

BRANCH TO 300

CALL B

MOVE P TO X

BRANCH TO 200

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

800

700600

500

400

300

200

100

2. Symbolic Resolution

1. Relocation Problem

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1. Relocation Problem1. Relocation Problem

Consider the execution begins with the instruction at the beginning of module A

BRANCH TO 200

The program would not branch to the intended instructionbecause MOVE P TO X is now at address 300

All memory reference instructions will fail for the same reason

This relocation problem occurs because each generated object module represents aseparate address space, starts at 0


2. Symbol Resolution Problem2. Symbol Resolution Problem

In the example, the procedure call instruction, CALL B at address 400 will not work

Because each module is translated by itself

the translator doesn’t know what address to insert into the CALL Bthe address of object module B is not known until linking time

This is requires symbol resolutionor resolving the external reference problem!

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Relocation MechanismsRelocation Mechanisms

On a machine with a segmented address spacesuch as Pentium IIPentium II,

theoretically each object module could have its own address spaceby being placed in its own segment

However, OS/2OS/2 is the only operating system for the Pentium IIPentium II that supports this concept

most OS, including Windows Windows and UNIX, UNIX, support only one linearaddress space

all the object modules must be merged into a single address space


Linking: Steps Linking: Steps (rough)(rough)

Linkers can be used to solve both

relocation and symbolic resolution problems

The linker merges the separate address spaces of the object modules into a single linear address space in the following steps:1. constructs a table of all the object modules and their lengths

2. Based on this table, it assigns a starting address to each object module

3. finds all the instructions that reference memory (relocation problem)a. adds to each a relocation constant equal to the starting address of its module

4. finds all the instructions that reference other modules (resolution problem)a. inserts the address of these procedures in place.

ModuleModuleABC D

LengthLength400600500300

Starting AddressStarting Address10050011001600

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0

1900MOVES S TO X

BRANCH TO 200

CALL D

MOVE R TO X

BRANCH TO 200

CALL C

MOVE Q TO X

BRANCH TO 300

CALL B

MOVE P TO X

BRANCH TO 200

1800

1700

1600

1500

1400

1300

1200

1100

1000

900800

700600

500

400

300

200

100

ObjectModule D

ObjectModule C

ObjectModule B

ObjectModule A

Address space of the program after the linker has performed 1- 4 steps.

MOVES S TO X

BRANCH TO 1800

CALL 1600

MOVE R TO X

BRANCH TO1300

CALL 1100

MOVE Q TO X

BRANCH TO 800

CALL 500

MOVE P TO X

BRANCH TO 300

1800

1700

1600

1500

1400

1300

1200

1100

1000

900

800

700600

500

400

300

200

100

0

ObjectModule D

ObjectModule C

ObjectModule B

ObjectModule A

Linker:1-4

1900






Database Technology




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