Software Engineering
Aug. 26, 2013

What is Software Engineering?

  -Not just writing code.

  -Entire software process from gathering information to design to coding
   to deployment to maintenance

  -Doing it economically
    + inside of a budget for both time and money

  -Quality Assurance

  -Teamwork!

Many parts & many details

  -Basic definition of SW Engineering is building quality SW inside a budget
   and doing it right.

Software is intangible
  You can't touch it!
  Hard to assess quality
  It is not like a bridge (think civil engineering)

Production (manufacturing)
  -Easy and cheap
  -CDs are inexpensive to manufacture
  -Storing data on CDs/DVDs is fast - use a burner
  -Downloading is fast (in general)

Costs for software are mainly in the development
  People's time is the largest cost by far
  Building software properly takes lots of time
  
  _The_Mythical_Man_Month_ shows that adding more people to a project adds 
  complexity.

  Some software tools are automated
    - Integrated Development Environments (IDEs)
       + Eclipse
       + Netbeans
       + Mono
       + Visual Studio
       + many others
  Real intelligence isn't there yet
    - IBM's Watson is close, but it won't write code for us

Software doesn't wear out physically
  -It isn't like a car or a bridge
  -Use it as many times as you want and it won't change

  -Rather, HW and SW platform changes cause SW to deteriorate

  -Sometimes we need a new build for an old algorithm because the previous
   build was of poor quality

  -People make mistakes
    + Might make changes without thinking about the ramifications

"Software Crisis"
  -Many people have been lax about building quality SW
  -Managers and Developers might not get along
    +Not making allowances for change
    +Not giving each other proper time
  -Working together and communication is key to solving this crisis

  -Problems cause by developers not getting along and not using good management
   techniques
    +time management
    +communication
    +flexible design and development

  Specification->Design->Development->Deployment->Maintenance-+
        ^                                                     |
        +-----------------------------------------------------+

  Developeres might not think about adding more lines or using short small 
  prototypes

The "crisis" can be solved as follows:

  Communicate with your fellow developers
  Use effective tools
  Make better tools as necessary
  Be kind to each other.
  
  Result: Increased productivity --> Happier developers, customers, users, and
  managers

Some General Types of SW

Custom - customer specific or in-house
       - might not be useful to others
   Ex: Air Traffic Control, Emergency Management, Quantitative Finance, etc.

Generic - open market (paid) or open source
  - many people use it
  - typically runs on a general purpose platform (e.g. PC, mobile, etc.)
  - may be more cost effective than custom SW if meets the needs of client

  Ex: OS, Internet Browser, Word Processing, etc.

Embedded - DVD/Blu-ray players <-- use Java and custom Linux
         - Router <-- custom Linux
         - Microwave
         - Cars/Trucks/Appliances
            May or may not be able to upgrade SW
            Might have to use special HW to flash upgrade or might have to 
            replace HW to get new SW

Other Classifications
  -Real Time (RT)
    Soft - generic applications, may run slower if not critical
    Hard - critical systems (Hospitals, Power tools, Airplanes, Cars)
         - if system fails to react something really bad might happen
  -Data Processing
    -Business SW like spreadsheets, PeopleSoft, etc.

  -Some SW has both aspects
    -new car computers record data useful for diagnosis
       -It is ok if you don't get everything
    -"drive-by-wire" - car steering wheel sends signal to computer then to
     steering hydraulics to turn wheels.
       +Failure to react could cause accident or death
    -So, cars have both Data Processing and RT Hard systems

Stakeholders - people who have roles in a SW project
   - might have an agenda or motivation
   
   - Users - use system
      + Might lose job because of SW
      + Might have easier job because of SW

   - Client - decides what they want in SW
      + Developer/Development Manager gets information from them
      + might have goals
        -Increase profit
        -Replace employees with SW
        -Make workplace safer
        -Make employee life easier

   - Developer - Write/Maintain SW
      May have specific role
        - DB, requirements, tech. writer, configuration management, etc.
        - Wants to work on interesting project

   - Dev. Manager - runs SW company or part of it
      - Might have business training
      - Wants customer/client to be happy
      - Wants to use least resources
      - Must have good communication with developers and client

SW Quality
  Many attributes
  Means different things to different people

  - Usability - how easy it is to use the SW
  - Efficiency - how much resources are used
     + CPU Time, Bandwidth, Disk Use, Memory
  - Reliability - failure rate
  - Maintainability - ease of change to SW
  - Reusability - how easy SW may be used in other systems