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Ada Experiences

Ada Experiences. Panel Chair John McCormick, University of Northern Iowa Panelists Robert Lockwood Alliant Techsystems Bill Rusinak Lockheed-Martin David Glessner Rockwell-Collins Elizabeth Theesfeld Honeywell. Bob Lockwood. Software Engineering Manager

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Ada Experiences

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  1. Ada Experiences Panel Chair John McCormick, University of Northern Iowa Panelists Robert Lockwood Alliant Techsystems Bill Rusinak Lockheed-Martin David Glessner Rockwell-Collins Elizabeth Theesfeld Honeywell SIGAda 2001 Panel: Ada Experiences

  2. Bob Lockwood • Software Engineering Manager • Alliant Techsystems – Integrated Defense Company • 600 Second Street NEHopkins, MN 55345952-931-5285 • Robert_lockwood@atk.com SIGAda 2001 Panel: Ada Experiences

  3. Software Engineering Experience • Applications: Military – Command, Control, Communications • Primary Projects – Real-Time, Embedded • Experience – 9 years hardware developer – 25 years software developer – 16 years working with Ada-83/Ada-95 • Company Certifications – ISO9001, CP2 • Platforms – Intel 80x86/i960, PowerPC 5xx, 6xx, 7xx • Operating Systems – Bare Machine, VRTX, VxWorks, Nucleus, LynxOS SIGAda 2001 Panel: Ada Experiences

  4. Project • Military Vehicle Fire Control • Navigation • Communication • Ballistics • Weapon Control • Operator Interface • Intel 80x86/i960 platforms • Why Ada • First major vehicle project • Ada Mandate • Highly Embedded C3 SIGAda 2001 Panel: Ada Experiences

  5. Project (cont) • Size • Tactical Software 200,000 sloc • Support Software 300,000 sloc • Why Easy • Strongly typed • Compile-Time checks • Why Hard • Lack of experienced programmers • Extensive training necessary SIGAda 2001 Panel: Ada Experiences

  6. Project (cont) • Comparisons (Ada vs. xyz) • Fewer dumb errors • More robust runtime code • Higher reliability (with same compiler) • More automated testing • Lessons Learned • Advantage for multiple development groups • Limit language usage • Most errors found at compile time • Identify interfaces early in project SIGAda 2001 Panel: Ada Experiences

  7. Bill Rusinak Sr Software Engineering Manager Lockheed Martin Tactical Defense Systems Eagan, MN 651-456-2222 william.a.rusinak@lmco.com SIGAda 2001 Panel: Ada Experiences

  8. Application: Military embedded systems (Maritime Surveillance Aircraft (MSA)) • Projects are real-time applications • Experience: 23 years (12 years with Ada) • Lockheed Martin TDS is CMM level 4, ISO 9001 • Platforms: Sun/Unix host development targeted to several platforms (Motorola 680x0, PowerPC) SIGAda 2001 Panel: Ada Experiences

  9. Ada Experiences in MSA • Lockheed Martin Eagan supplies mission software for almost all of the world’s P-3 aircraft (US Navy, Japan, Australia, Norway, the Netherlands) • Replacement of 1970’s vintage hardware and software began in 1989 with the US Navy • First system had 3 Motorola 68030 processors • Mission and System Test software rewritten (Ada 83) • Evolving (e.g., X-Windows, Sparc) • Ada software is 1 to 1.2 million lines of non-comment, non-blank code SIGAda 2001 Panel: Ada Experiences

  10. Positive Experiences • Ada tasking was used without problem • Task deadlocks were never encountered due to application of good design methodology • Use of separates promotes design • Ada code usable as PDL • Original architecture has been flexible • Ported to different hosts • Maintained through different toolsets • Maintained by several customers SIGAda 2001 Panel: Ada Experiences

  11. Negative Experiences • Task stack sizing is risky in a limited memory system (only your linker knows for sure) • Exceptions happen when you least expect them – it is easy to leave a semaphore seized • Separates increase compilation time • Use a “de-separatizer” • Overloading of names can be confusing • Over and under use of types and exceptions • Takes experience to find the middle ground SIGAda 2001 Panel: Ada Experiences

  12. Negative Experiences • Ada 83 lacking protection mechanisms and multi-processor support • Language needs space for stacks, exceptions, and can produce big programs • Need more support/tooling SIGAda 2001 Panel: Ada Experiences

  13. In General • Define tasks up front • Enforce concrete rules and use a few protection mechanisms • Closely monitor dependencies during design • Structure libraries properly • Do it again (but with Ada 95) SIGAda 2001 Panel: Ada Experiences

  14. David W. Glessner • Senior Software Engineer, Navigation and Control Group, Advanced Technology Center • Rockwell Collins400 Collins Road NE Cedar Rapids, Iowa 52498 319-295-6012 • dwglessn@rockwellcollins.com SIGAda 2001 Panel: Ada Experiences

  15. Software Engineering Experience • Rockwell Collins: Navigation systems (commercial and military) • Pre-Rockwell Collins: Commercial RF systems (broadcast radio and TV, paging) • 15 years in software, last 3 with Ada. Most of the rest with C. Some Assembly. • Target platforms: Mostly custom boards (AAMP, 68302, 68HC16, 8088, Z-80), some PCs. Various commercial and custom RTOSes. • Development platforms: Unix (Sun, HP, DEC), Windows, VAX (using Apex RCI). SIGAda 2001 Panel: Ada Experiences

  16. SNIPER/SUOSAS • Sensor Integration for robust navigation • GPS, IMU, Loran, barometric altimeter, TDOA radio, vision. • DARPA funded. • Reused Ada software from earlier GPS/IMU projects. • 80,000 LOC (38,000 non-comment non-blank) • First exposure to Ada. SIGAda 2001 Panel: Ada Experiences

  17. SNIPER/SUOSAS (cont) • Good: • Package specs. Enumerations. Ranges. • Rational Apex. Rational Compilation Integrator (RCI). • Bad: • Flaky hardware. • Tools. • Compile times. • Didn't "trust" the language. • Code bloat (possibly due to Ada 83 missing generic formal packages or pointers to subprograms). • Result: Successful field trials for both projects. SUOSAS continuing. SIGAda 2001 Panel: Ada Experiences

  18. Various GPS-related projects(Commercial GPS, Artillery) • Ada chosen on a DARPA project in 1980s due to DOD mandate. Based on earlier Jovial development. Some parts of software still have a Jovial "feel" e.g., "for ii in 1..10" • 102,000 LOC (44,000 non-comment, non-blank) • Analysis and modifications of some pretty complicated code. SIGAda 2001 Panel: Ada Experiences

  19. Various GPS-related projects (cont) • Good • Apex browsing! • Types make modifications easier to analyze. • Bad • Apex configuration control (Summit/CM). • Cumbersome to see differences between versions. (Local policies probably contributed to this.) • Results: Successful lab trials. SIGAda 2001 Panel: Ada Experiences

  20. Automatic Dependent Surveillance – Broadcast (ADS-B) • New development integrated with existing Traffic Alert and Collision Avoidance System (TCAS). • ADS-B: 8,000 LOC (4,400 non-comment, non-blank) • similar amount for additional analysis and simulation • Mixture of Apex Ada 95 (Sun host) and DDC Ada 83 (AAMP-based TCAS target). • developed mainly on the Sun • late integration (risky, but worked quite well) SIGAda 2001 Panel: Ada Experiences

  21. Automatic Dependent Surveillance – Broadcast (ADS-B) (cont) • Good • Ada 95/83 portability. Ada 95 tasking. • GNAT for the PC. • Ada contributes to thoroughness; exposed some algorithm weaknesses. • Bad • Ada design flaw? “Cos(Long_Float(2.0*Pi/I))” • Stack alignment bug during integration. • Result: Successful flight tests with other vendors. Work continuing. SIGAda 2001 Panel: Ada Experiences

  22. Commercial Aviation Products Elizabeth Theesfeld 6s Black Belt/Principal Software Engineer Honeywell Commercial Aviation Products (CAP) 8840 Evergreen Blvd Coon Rapids, MN 55433 (763) 957-3626 elizabeth.theesfeld@honeywell.com SIGAda 2001 Panel: Ada Experiences

  23. Commercial Aviation Products • Background Information • 14 Years of experience in real-time embedded software for both Military and Commercial Avionics. • 7 Years of experience with Ada. SIGAda 2001 Panel: Ada Experiences

  24. Commercial Aviation Products • CAP has only one program developed in Ada • Secondary Attitude and Air Data Reference Unit (SAARU) for the Boeing 777 Aircraft • 60,000 Lines of Code • Real-Time embedded software on a 68040 processor • Object Oriented Design using Booch Diagrams • DO-178B Compliant SIGAda 2001 Panel: Ada Experiences

  25. Commercial Aviation Products • Positives for using Ada at CAP • Eliminated the need for software-software integration • Strong data typing • Strong software architecture • Was able to hand the program over to a new team that did not work on the original development for airline updates with minimal impact • Negatives for using Ada at CAP • Not many Ada programmers available SIGAda 2001 Panel: Ada Experiences

  26. Commercial Aviation Products • Reliability of SAARU software in the field • The 777 was certified in 1995 • To date we have had 0 software defects recorded SIGAda 2001 Panel: Ada Experiences

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