Ada, Model Railroading, and Software Engineering Education

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Ada, Model Railroading, and Software Engineering
Education

• John W. McCormick
• University of Northern Iowa

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Computer Controlled Systems Study Option

• For students interested in the specification,
  design, and implementation of real-time embedded
  software.
• Core courses from the ACM curriculum.
• Additional courses in
• Continuous mathematics
• Physics
• Electronics

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CSC 416Real-Time Systems

• A capstone course.
• To perform well students must integrate knowledge
  from
• Computer Science
• Physics / Electronics
• English
• Mathematics

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CSC 416Real-Time Systems

• Students are exposed to fundamental scientific
  issues in real-time computing and practical
  skills of software development.
• Goal is to train software engineers capable of
  working as part of a development team.
• Many topics covered at a survey level.

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The Laboratory
A major problem with teaching real-time embedded
software engineering is finding suitable
equipment for assignments and projects.
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The Laboratory

• Simulators
• Do not provide many of the frustrating problems
  associated with actual physical systems
• Lack of experience with real systems is one
  reason cited by those who would exclude computer
  science graduates from development teams.

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The Laboratory

• The problem now becomes finding a physical system
  for students to control
• In 1984 I began using a large model railroad in
  my course.
• Why a model railroad?
• Lets look at some pictures!

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Projects in C
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Projects in Ada
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Why does Ada succeed where C fails?

• Modeling of scalar quantities
• Strong typing
• Range checking
• Enumeration types
• Parameter modes
• Named parameter association

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Why does Ada succeed where C fails?

• Arrays whose indices do not begin at zero
• Representation clauses for modeling device
  registers
• Record types
• Enumeration types

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Why does Ada succeed where C fails?

• High level of abstraction for tasking.
• Ada students use rendezvous
• C students used semaphores
• Exception handling
• Encapsulation
• Package specifications and bodies
• Compilation model
• Obsolete units are detected!
• No make files!

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Laboratory Assignments

• Code for learning Ada features
• Basic language features
• Packages
• Tasking
• Generics
• Exceptions

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LaboratoryAssignments

• Code for the course project
• Polling and interrupt based device drivers
• Implementation of whistle class
• Implementation of turnout class
• Electro-mechanical devices which sometimes fail
  to move correctly
• Code must detect and attempt to correct the
  problem
• Code derived from a state machine model

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Project Specification Design Deliverables

• System concept document
• Detailed user manual
• Rumbaugh OMT documents
• Object model diagrams
• Dynamic model diagrams
• Functional model diagrams
• Data dictionary
• Package specifications
• Package test plans

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Minimum Project Requirements

• Multiple trains
• At least one train controlled by a human engineer
• No collisions
• Detect and recover from hardware failures
• Turnouts
• Sensors
• Lost cars
• Devious professors

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Popular Project Themes

• Races
• Train wars
• Scheduling (usually combined with project in the
  AI class)

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Where do we gofrom here?
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• Over 50 Schools have inquired about duplicating
  the laboratory
• Only about 3 schools have actually built a model
  railroad
• Commercial interface boards too expensive
• Too much time or expertise required to build
  electronics in house
• My Solution
• Design and manufacture inexpensive plug-n-play
  model railroad interfaces

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