CIS 115

Lecture 25: Software Engineering

Early Programmers

Image Source: Wikipedia

1945 - 65: Early Software

• Many software pioneers were women!
• Early computers were very specialized; software was rewritten
• Led to high-order languages like FORTRAN, COBOL, ALGOL
• Conferences held in 1968 and 1969 started the field

1965 - 85: Software Crisis

• Many projects ran over budget and schedule
• Bad software could cause damage or even death!
• The field needed to be standardized

1985 - 89: No Silver Bullet

• Unfortunately, no single solution to make software better
• 1995 study: 1/2 of software projects operational but not successful
• Average software project overshoots schedule by half
• 3/4 of large software projects either not used or don't meet all requirements

1990 - 2000: Rise of the Internet

• Software made more use of the network
• Graphics became more important
• Software was becoming more and more consumer focused
• Viruses, search engines, email, etc.

2000 - Present: Lightweight Methodologies

• Agile development: focus on velocity
• Use of models and reused code to ease development
• Software "families" avoid the need to recreate software from scratch

Software Development Life Cycle

• Requirements
• Specification
• Architecture
• Construction & Design
• Testing & Debugging
• Deployment & Maintenance

Requirements Elicitation

• Contact stakeholders
• Gather information
• List requirements
• Determine target & goals
• Use Cases
• Verify correctness

Requirements

Image Source: Wikipedia

Use Cases

Image Source: Wikipedia

Software Specification

• Describes how the system should function
• Lists inputs and outputs
• Should clearly match the requirements

Software Specification

Image Source: Wikipedia

Software Architecture

• High-level overview of how the software should be built
• Accounts for multiple stakeholders, separation of concerns, recurring styles or models, etc.
• Gives developers a framework to work with

Software Design & Construction

• Developers refine the architecture diagram by adding features and solidifying individual design components
• Usually several layers of diagrams are made for larger software projects

UML Diagram

Image Source: Oracle

Software Testing & Debugging

• Verifying the software works correctly
• Errors can be introduced at any step of the process
• Unfixed errors can cause massive problems down the road
• The longer an error is unfixed, the more it takes to fix it

Deployment & Maintenance

• Once software is created, it must be given to clients
• Larger software packages require more deployment effort
• Once software is deployed, bugs may still be found and must be patched
• Updates may be issued to add more features

Development Models

• Code & Fix
• Waterfall
• Iterative / Incremental
• Spiral
• Agile

Waterfall

Image Source: Wikipedia

Iterative

Image Source: Wikipedia

Spiral

Image Source: Wikipedia

Agile (Scrum)

Image Source: Wikipedia

Globalization

• Software is GLOBAL!
• Companies can "follow the sun"
• Development can happen 24 hours a day
• Communication and collaboration is key to success

Assignments

• Textbook Section Draft - Due Friday 11/21 10:00 PM via K-State Canvas
• Textbook Final Version - Due 12/12 10:00 PM
• Blog 12: Robots of the Future - Due 12/1 10:00 PM
• Scratch Mars Rover - Due 12/2 10:00 PM

Blog 12: Robots of the Future

Robots are becoming more and more prevalent in industry today, but they haven't quite made the big inroads into our daily life that was predicted 20 years about. Tell us your predictions for the field of robotics for the next 20 years. Things to think about:

• If you could afford a robot housekeeper, would you want one?
• Would you like to own a driverless car? Why or why not?
• What do you think robots WON'T be able to do by then?
• What area of life do you think robots will have the biggest impact in?

Work on Final Project Drafts