lab01 introduction

8/12/2019 Lab01 Introduction

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Software EngineeringLab Session

Session 1 Introduction to thepracticum

Jorge Aranda, 2005


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Overview

What is it about?

Why are we doing this?

How to get a good grade

The Personal Software Process

Assignment 1


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What is it about?

Based on Watts Humphreys PersonalSoftware Process

Outlined inA Discipline for Software

Engineering You should have finished reading Chapters 1-4

already!

Six relatively easy programming assignments On C

Focus on learning and understanding the process

Assignments map to Humphreys 1A-6A exercises


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What is it about?

Youll be submitting one assignment perweek

Except on Thanksgiving and the midterm week

Therell also be weekly reading assignments

The process will be increasingly elaboratedas we go along


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Hardly surprising facts:

1 Most software projects go wrong

2 Most software projects do not follow *any*

development process 3 Software projects that do follow some

process have a much better chance of survival

It really can be almost any process

Extreme Programming and other Agile styles Cleanroom

Capability Maturity Model (CMM)


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But software engineers are frequently too busy tolearn software processes

The best time for you to learn them is now

We chose the Personal Software Process (PSP) Will help you think about software development in a

disciplined way

Will help you to know your own strengths andweaknesses, and to improve them

Its a personal activity, but it can be extended to teamsand organizations

Itll look good on your resume


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Think about the term Software Engineer

What defines an engineer?

What do engineers measure/control/plan?

Do software developers reallydo engineering?


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Software engineering:

Management of resources

Main resource is the engineers own time and whatshe does with it!

Estimation

Progress tracking

Quality Assurance

Defects injected into product

Conformance of product to requirements


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Why are we doing this? Would you be able to respond accurately to these

questions? On average, how many defects do you inject in the code you

write (per 1,000 lines of code)?

How many of those defects are coding errors, and how manyare design or requirements errors?

What percentage of your time goes into coding? Whatpercentage goes into fixing defects?

How many lines of code have you written in the past year?

How many classes, methods or routines? Of what kind?

By what percentage are your estimates normally off?

Developers are all different what are your weaknesses andstrengths as a developer? (Fast coder, high quality, good

architecture?)


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This practicum will help you find answers to thosequestions

Its harder than it sounds! You need to be disciplined about your own work

Use a structured process

Keep track of a lot of little details

Little by little youll get used to it

If you like it, great! Youll have an important skill foryour professional career.

And if you dont like it, remember you only have todo itthis term


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How to get a good grade

Short story: Its very easy, really. Just follow the process thoroughly

and youll do great.

Longer story: Read A Discipline for Software Engineering

conscientiously. Warning: Humphrey is not especially fun or concise

Stick to the process while doing the exercises

Use the forms appropriately Extract insights from your own work, and report them

Reflections on your performance and on the process

Work on two levels Quality of your code, quality of your process

Submit your assignments on time


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Basic idea #1: Measure yourself Know how much time you spend in

programming tasks

Know how many defects your code has

Know how well you estimate your effort

You cant control what you cant measure

Basic idea #2: Control yourself Improve your estimates

Improve the quality of your software


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PSP is incremental:

PSP0

Whatever youre currently doing, plus somemeasurements

PSP0.1 -> PSP1 -> PSP1.1

Increasingly detailed estimates, controls

You start to apply regression to your estimates

You start getting efficiency and other quality metrics

This is as far as well go

PSP2 -> PSP3

We wont have the time to go there

I admit it does get hairy at this point


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PSP0 Youll be using three forms:

Project Plan Summary

Time Recording Log

Defect Recording Log

Refer to Humphreys book for correct usage of theseforms

Project Plan Summary After understanding the requirements, estimate how many

minutes will the assignment take

After finishing the assignment, write down how much timeit actually took, and how many defects you found

It is OK to be absolutely wrong in your initialestimates


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PSP0 Time Recording Log

Have it handy when you work on your assignments

Record everything

If you get up from your desk, get a call, read emailmake sure your log has the corresponding InterruptionTime entries

Some details will feel embarrassing (two hours fixing abug, for example). Record them anyway

Use minutes, not hours

Low-tech works better than hi-tech at this point

Use Humphreys classification of activities:

Planning, Design, Code, Compile, Test, Postmortem


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PSP0

Defect Recording Log

Again, record everydefect

If you designed your routines incorrectly, write thedefect in the log

If you made an off-by-one error, write it in the log

If your automated tests were wrong, write it in the log

you get the idea

If unsure as to what defect type each defect belongsto, write your assumptions in the defect description


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The three forms of PSP0 will become thefoundation of later assignments It willfeel weird at the beginning

Give it some time

With time, you will be recording your time anddefects naturally Appreciating the advantages of this process will take

a while

It shouldnt interfere with your creativeprocesses!


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Assignment 1

Write a program to calculate the mean and standarddeviation of a sample of nreal numbers.

Hints Remember were interested in that you learn a process, notin

that you know how to program a standard deviation routine! Your report on insights and impressions is important it will

show us if your brain is engaged in the exercise or not

Make sure you understand the requirements before you startcoding

Document all assumptions

Automated tests are (almost) always better than manual tests

Be nice to the TA that will mark your work and that of 150other persons

Although it shouldnt take too long, start soon. We can tell ifyoure rushing to finish your assignment


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Am I missing something?

Questions?

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