Software and systems engineering Paulo Borba

Informatics Center

Federal University of Pernambuco

[email protected] ◈ twitter.com/pauloborba

Introduction to software and systems engineering

Engineering is…

the application of science

to the design, building and use

of machines, construction, etc. The Concise Oxford Dictionary

System =

Software +

People + Data +

Hardware

(computers, sensors,

phones, watches,

drones, etc.)

Software and systems engineering is concerned with…

Quality

and

Productivity

Serious software and systems development

http://www.home-dzine.co.za/diy/diy-doghouse.htm

http://silviarangel.wix.com/fotografa

It’s not about small versus large

http://transmissionsmedia.com/the-inexplicable-precision-in-the-construction-of-the-great-pyramid-at-giza/

Most software today is very much like an Egyptian pyramid with millions of bricks piled on top of each other, with no structural integrity, but just done by brute force and thousands of slaves.

Alan Kay

http://en.wikipedia.org/wiki/Alan_Kay

So our main goal is… •

Software and systems quality

•

Software and systems development and operation productivity

•

costs and deadlines

Relevance of software quality ■

Availability of important services

• home banking

• communication

■

People’s safety

• health monitoring

• air traffic control

• ABS

Practical impact ■

Companies competitiveness

■

Better products, smaller costs (long term)

■

Attraction of new companies to local ecosystems

• investments, more taxes

Software development issues (crisis?) ■ ■

■ ■

Project cancellation rate of 25%

• 31% in another study, 16% are successful

development time and cost go well beyond the estimative

• in 53% of the analyzed projects

75% of the analyzed systems do not work as planned

Difficult reuse and maintenance

Even worse in common scenarios…

Different clients, different products

http://www.androidauthority.com

Little reuse and agility, high costs Even with

Android!

Little modularity and agility, more defects, high costs {GameMenu.MENU_OPTION_ID_PLAY,GameMenu.ME NU_OPTION_ID_C ONFIG_SOUND,GameMenu.MENU_OPTION_ID_ARENA _SHOW_RANKING,GameMenu.MENU_OPTION_ID_HELP }; //#else //#public final int[] mainMenuCommands = {GameMenu.MENU_OPTION_ID_PLAY,GameMenu.MENU _OPTION_ID_CONFIG_SOUND,GameMenu.MENU_OPTI ON_ID_HELP}; //#endif /** Main pause menu options. Shown in the menu when game is paused */

private final int[] mainPauseMenuCommands = { GameMenu.MENU_OPTION_ID_RESUME,GameMenu.ME NU_OPTION_ID_TRACK_11,GameMenu.MENU_OPTIO N_ID_TRACK_12 }private final int[] helpCommands = {

GameMenu.MENU_OPTION_ID_HELP_GOAL, GameMenu.MENU_OPTION_ID_HELP_STRAIGHTS, GameMenu.MENU_OPTION_ID_HELP_CURVES, GameMenu.MENU_OPTION_ID_HELP_ABOUT };

/** Pause exit menu options */

private final int[] pauseMenuRestartCommands = { GameMenu.MENU_OPTION_ID_PAUSE_RESTART_YES , GameMenu.MENU_OPTION_ID_PAUSE_RESTART_NO }; private final int[] endRaceMenuCommands = { GameMenu.MENU_OPTION_ID_ARENA_POST_SCOR E, GameMenu.MENU_OPTION_ID_END_RACE_RETRY, GameMenu.MENU_OPTION_ID_END_RACE_SELECT_ TRACK, GameMenu.MENU_OPTION_ID_BACK_MAIN_MENU };\ //# private final int[] endRaceMenuCommands = { //# GameMenu.MENU_OPTION_ID_END_RACE_RETRY, //# GameMenu.MENU_OPTION_ID_END_RACE_SELECT_TR ACK, //# GameMenu.MENU_OPTION_ID_BACK_MAIN_MENU //# }; */ private int PREVIOUS_KEY_CODE = MainCanvas.UP_PRESSED;

!

private int NEXT_KEY_CODE = MainCanvas.DOWN_PRESSED; /** Title of the menu*/

private String menuTitle;

private Image rewardUserImageMainMenu;public static final int TRACK_SELECTION_MENU = 5; //#if feature_arena_enabled /** * Post ranking menu */ public static final int POST_SCORE_MENU = 10; //#endif

!! !

package com.meantime.j2me.gui;

import java.util.Vector;

import com.meantime.j2me.util.Screen;

import com.meantime.j2me.util.bvg.BVGAnimator;

//#if device_graphics_transform_midp2

//# import javax.microedition.lcdui.game.Sprite;

//#else import com.meantime.j2me.util.game.Sprite; private static final int PRESENTATION_BACKGROUND_COLOR = 0x000000;

!

//#if device_screen_128x128



/** Initial car animation position x */

private static final int CAR_LEFT_INITIAL_POS_X = -78;



/** Initial car animation position y */

private static final int CAR_LEFT_POS_Y = 31;



/** Initial tire animation position y */

//#

//#endif

/** Used to left tire animatiom position x */

private int currentTireleftPosX; private BVGAnimator presentation_second_bvg;

private BVGAnimator arena_bvg; gff

!

//# Dffdsffffffffffffffffffffffffffffff Ghrwds { /** Constants to paint the scroll bar */ private static final int ARENA_SCROLL_HEIGHT = 92; private static final int ARENA_SCROLL_POS_Y = 17; //#elif device_screen_128x117

//#

//# /** Constants to paint the scroll bar */

//# private static final int ARENA_SCROLL_HEIGHT = 81;

//# private static final int ARENA_SCROLL_POS_Y = 16;

//#if sku_id_se1 //# //#g = originalG; //#g.drawImage(bufferImg, 0, 0, 0); //# //#endif} catch(Exception e){ e.printStackTrace();

}

}

public void changeScreen (innewScreenIndex; this.nextScreenMode = newScreenMode; this.nextScreenParam = param; /** * Shows the last screen shown.

* If there's not a last screen (i.e., the screen index in

* the stack is public void goBack() { int[] screenData = this.popSc // avoid mainCanvas to go back to a waiting server screen if (screenData[STACK_SCREEN_MODE_INDEX] == Resources.MAIN_SCREEN_MODE_ARENA_WAITING_ SERVER) { this.goBack(); return;this.changeScreen(screenData[STACK_SCREEN_ INDEX], screenData[STACK_SCREEN_MODE_INDEX],

screenData[STACK_PARAM_INDEX]);

}

this.goBack = true; }//#public void commandAction(Command c, Displayable d) {

//#if (c == this.leftCommand) { //#this.keyPressed(LEFT_SOFT_KEY); //#} else if (c == this.rightCommand) { //#this.keyPressed(RIGHT_SOFT_KEY); //#} //#} //# //#endif

Cancellations 10240 5120 2560 1280 640 320 Points 160 80 40 20 10 0

0

10

20

30

40

50 %

Delays

Points

10240 5120 2560 1280 640 320 160 80 40 20 10 0

Estimation Real

0

10

20

30

40

50

60 Months

Essential causes of software issues •

Increasing systems complexity

•

Formalization difficulties and costs

Accidental causes of software issues • • •

Lack of proper education

Poor quality of languages, tools, techniques, and processes

Organizational issues

• poor management

• conflicts

Software quality factors, focus on ethics and business value ■

Correctness

■

Robustness

■

Extensibility

■

Reusability

■

Compatibility

■

Portability

More factors, internal and external ■

Performance

■

Scalability

■

Integrity, privacy and security

■

Usability

■

Flexibility

■

Fault tolerance

Why would those factors be important for a store automation system?

Not only quality, but productivity too ■

Reduced development cost

• Consuming company wishes to invest little in software

• Producing company should offer “inexpensive software"

■

Reduced development time

• Quick support and attention to market needs

“Inexpensive software” Not only a result of lower development costs, but also of the cost distribution among a number of clients

!

Reuse, extensibility and flexibility are important

factors for achieving such distribution

Trade-offs between quality and productivity • Investing too much in quality can reduce productivity in the short term

• Neglecting quality can impact

productivity even in the short term

• Professional ethics should not be part of the trade-off

Course overview

Starting a new job… Tasks • Defining, maintaining and managing requirements

• Implementing, maintaining and executing tests

• Implementing and maintaining features

• Creating or adapting features

• Finding and fixing bugs

• Refactoring

• Finding and fixing reuse and modularity issues

• Managing software project

• Managing tasks, configurations and changes

Starting a new job… Background • Process and collaboration technologies

• git, github, modular development

• Software architecture concepts

• web architecture, patterns

• Programming and testing technologies for SaaS (software as a service)

• groovy, grails, HTML, Javascript, cucumber, refactoring

• Modularity and reuse tools

• code clone detection, quality metrics analysis

System • RGMS

• Redu

• other existing systems written in Grails or Rails

Course structure Study and analysis of site material

Requirements

Class discussion and evaluation

Testing Implementation Refactoring Management

Project activities, discussion and evaluation

Project results presentation and evaluation

https://sites.google.com/a/ cin.ufpe.br/engenharia-desoftware-e-sistemas-2014-2/

!

http://is.gd/Zuhc0Y

Introduce yourself... • Name

• What do you expect from this course?

Software and systems engineering Paulo Borba

Informatics Center

Federal University of Pernambuco

[email protected] ◈ twitter.com/pauloborba