Module 1: Introduction to SEng 5831 RealTime and Embedded Systems

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Module 1Introduction to SEng 5831Real-Time
and Embedded Systems
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Module Outline

• Instructor, TA, and class introductions and
  interests
• What are embedded systems? What is different?
• Course topics, materials, assignments
• Relationships to core MSSE courses

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Introductions

• Steve Vestal, Instructor
• steve.vestal_at_honeywell.com
• 612-951-7049
• Ph.D. Computer Science, University of Washington
• Honeywell Labs, Aerospace Advanced Technology
• Areas of experience
• Real-Time scheduling
• System configuration and verification
• Safety and reliability modeling
• Daniel Acuna, TA
• acuna_at_cs.umn.edu
• 612-626-8848
• Ph.D. Student, Computer Science
• Class introductions (at end?)

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What is an Embedded System?

• A special-purpose computer system usually built
  into a larger device. An embedded system is
  required to meet very different requirements than
  a general-purpose personal computer. (Wikipedia)
• A specialized computer system that is part of a
  larger system or machine. (Webopedia)
• Devices used to control, monitor or assist the
  operation of equipment, machinery or plant.
  "Embedded" reflects the fact that they are an
  integral part of the system. (IEEE Y2K Policy
  Site)

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Why is Embedded Computing Different?

• Different hosted application disciplines
  domains, e.g.
• Mechanical, chemical, control engineering .
• Aerospace, automotive, medical, industrial
  process,
• User interacts with the containing product, not
  the computer
• Explicit (and sometimes stringent) timing
  requirements
• Explicit (and sometimes stringent)
  safety/dependability requirements
• Physical and environmental constraints
• Recurring costs (production maintenance)
  dominate NRE
• Multi-disciplinary, software/hardware
  co-development

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General Course Comments

• An introduction to multiple topics, not an
  in-depth study of one
• 3 topics, 5 lectures each
• enable you to locate and use resources
• Synergize with, not duplicate, core MSSE courses
• Adapt to students background, interests and
  goals
• choice of projects

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Three Topics

• Real-time allocation and scheduling
• Safety and dependability
• Software/hardware co-development

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Real-Time Allocation Scheduling

• Scheduling allocation problems can be hard
• Determining system-level requirements (e.g.
  end-to-end deadlines) can be hard
• Determining component-level properties (e.g.
  WCET) can be hard
• Timing is a complicating non-orthogonal issue
  (e.g. coding guidelines, task models)
• Impacts amount of hardware required (hence
  recurring cost, size, weight, power, )

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Safety Dependability

• Failures may have high severity (damaged
  property, lost lives)
• Regulated certification requirements
• Safety/dependability is a complicating
  non-orthogonal issue
• VV/certification cost is often gt50 of
  development cost
• Redundancy impacts amount of hardware required
  (hence recurring cost, size, weight, power, )

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Software/Hardware Co-Development

• Custom HW (especially IO), HW/SW interface may be
  complex
• Partitioning of functionality into HW vs. SW may
  be non-trivial
• Physical placement of hardware and wiring may be
  complex
• Access to final HW may be limited (or impossible)
  during SW development
• RTOS/middleware may be limited, cross-development
  may be awkward, more static configuration
• The SW/HW line is blurring (e.g. FPGAs)
• Long lifetimes, obsolescence management is an
  issue

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Course Materials

• Real-Time Systems by Jane W. S. Liu
• Safeware System Safety and Computers by Nancy G.
  Leveson
• Industry standards and handbooks (will post)
• Publications and technical reports (will post)
• http//www-users.itlabs.umn.edu/classes/Spring-200
  8/seng5831/

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Assignments

• Reading assignments
• Three mini-projects, one per topic area
  (student-selectable), e.g.
• Implement apply a scheduling algorithm
• Implement apply a schedulability analysis
  algorithm
• Download apply a ROTS schedulability analysis
  tool
• Measure, analyze, discuss thread execution times
• Fault-tree system safety model
• Markov reliability/availability model
• Presentation or report on a safety standard or
  guideline
• Presentation or report on an accident
• Embedded system architecture specification
• UI design for an IO-constrained product (e.g.
  smart thermostat, door lock)
• Hands-on cross-development exercise (e.g. robot
  maze-runner)
• Open to comparable student proposals

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MSSE Core Courses

• SE 5801 Software Engineering I The Software
  Life-Cycle, Requirements Specification, and
  Design
• SE 5852 Quality Assurance and Process
  Improvement
• SE 5851 Software Project Management
• Every life cycle phase is impacted (e.g. system
  safety process, certification processes).
• Additional attributes may need to be managed
  (e.g. hardware resource management)
• A system, not just a software, development
  process (e.g. multi-disciplinary,
  hardware/software co-development).
• Regulatory requirements apply to process and
  quality assurance, not just certain verification
  activities.
• Recurring costs often dwarf nonrecurring
  (development) costs.

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MSSE Core Courses

• SE 5707 Principles and Use of Database
  Management Systems
• Dependability and timing requirements
• Specialized data structures and queries (e.g.
  terrain, 3D object, signal history databases)
• Usually smaller in size and less distributed (but
  thats changing!)
• SE 5802 Software Engineering II Advanced
  Software Engineering
• Not just OO, functional and data flow patterns
  also
• Software/hardware co-design
• Restrictive guidelines for safety-critical
  software

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MSSE Core Courses

• SE 5811 Software Testing and Verification
• Over 50 of embedded software cost is VV
• Testing is only one VV method, e.g. analysis,
  review
• Influenced by standards and regulatory
  authorities
• SE 5115 Graphical User Interface Design and
  Evaluation
• User interacts with a device, not a computer
• Differing user task models (e.g. pilots, doctors)
• Differing devices (e.g. cockpit displays
  controls)
• Limited UI capabilities (e.g. thermostat)
• Safety requirements (e.g. safety inter-locks)

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MSSE Core Courses

• SE 5861 Introduction to Software Architecture
• System (HWSW) architecture
• Special patterns (e.g. periodic tasking, triple
  modular redundancy)

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• Student introductions