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October 4, 2001SIGAda 2001 Panel: Ada Experiences 1 Ada Experiences Panel Chair John McCormick, University of Northern Iowa Panelists Robert LockwoodAlliant.

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Presentation on theme: "October 4, 2001SIGAda 2001 Panel: Ada Experiences 1 Ada Experiences Panel Chair John McCormick, University of Northern Iowa Panelists Robert LockwoodAlliant."— Presentation transcript:

1 October 4, 2001SIGAda 2001 Panel: Ada Experiences 1 Ada Experiences Panel Chair John McCormick, University of Northern Iowa Panelists Robert LockwoodAlliant Techsystems Bill RusinakLockheed-Martin David GlessnerRockwell-Collins Elizabeth TheesfeldHoneywell

2 October 4, 2001SIGAda 2001 Panel: Ada Experiences 2 Bob Lockwood Software Engineering Manager Alliant Techsystems – Integrated Defense Company 600 Second Street NE Hopkins, MN

3 October 4, 2001SIGAda 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

4 October 4, 2001SIGAda 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

5 October 4, 2001SIGAda 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

6 October 4, 2001SIGAda 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

7 October 4, 2001SIGAda 2001 Panel: Ada Experiences 7 Sr Software Engineering Manager Lockheed Martin Tactical Defense Systems Eagan, MN Bill Rusinak

8 October 4, 2001SIGAda 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)

9 October 4, 2001SIGAda 2001 Panel: Ada Experiences 9 Ada Experiences in MSA Lockheed Martin Eagan supplies mission software for almost all of the worlds P-3 aircraft (US Navy, Japan, Australia, Norway, the Netherlands) Replacement of 1970s vintage hardware and software began in 1989 with the US Navy –First system had 3 Motorola 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

10 October 4, 2001SIGAda 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

11 October 4, 2001SIGAda 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

12 October 4, 2001SIGAda 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

13 October 4, 2001SIGAda 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)

14 October 4, 2001SIGAda 2001 Panel: Ada Experiences 14 Senior Software Engineer, Navigation and Control Group, Advanced Technology Center Rockwell Collins 400 Collins Road NE Cedar Rapids, Iowa David W. Glessner

15 October 4, 2001SIGAda 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).

16 October 4, 2001SIGAda 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.

17 October 4, 2001SIGAda 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.

18 October 4, 2001SIGAda 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 " 102,000 LOC (44,000 non-comment, non-blank) Analysis and modifications of some pretty complicated code.

19 October 4, 2001SIGAda 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.

20 October 4, 2001SIGAda 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)

21 October 4, 2001SIGAda 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.

22 October 4, 2001SIGAda 2001 Panel: Ada Experiences 22 Elizabeth Theesfeld 6 Black Belt/Principal Software Engineer Honeywell Commercial Aviation Products (CAP) 8840 Evergreen Blvd Coon Rapids, MN (763) Commercial Aviation Products

23 October 4, 2001SIGAda 2001 Panel: Ada Experiences 23 ( Background Information 14 Years of experience in real-time embedded software for both Military and Commercial Avionics. 7 Years of experience with Ada. Commercial Aviation Products

24 October 4, 2001SIGAda 2001 Panel: Ada Experiences 24 (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 processor Object Oriented Design using Booch Diagrams DO-178B Compliant Commercial Aviation Products

25 October 4, 2001SIGAda 2001 Panel: Ada Experiences 25 ( 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 Commercial Aviation Products

26 October 4, 2001SIGAda 2001 Panel: Ada Experiences 26 ( Reliability of SAARU software in the field The 777 was certified in 1995 To date we have had 0 software defects recorded Commercial Aviation Products


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