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Software and Digital Systems Safety (SDSS)

Research Program

Barbara LingbergFAA/AIR-120

SDSS Program SponsorMay 6, 2003

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Acronym List

• AVSI Aerospace Vehicle Systems Institute• COTS Commercial-off-the-shelf• CSTA Chief Scientific and Technical

Advisor• FAA Federal Aviation Administration• FPGA Field-Programmable Gate Array• FY Fiscal Year• HUMS Health Usage Monitoring System• IMA Integrated Modular Avionics• ISS Information Systems Security

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Acronym List (cont)

• IT Information Technology• LAN Local Area Network• MC/DC Modified Condition/Decision Coverage• NASA National Aeronautics & Space

Administration• OO Object-oriented• OS Operating System• RTOS Real-Time Operating System• SDSS Software and Digital Systems Safety• TCRG Technical Community Research Group

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Briefing Outline

• SDSS Research Program Purpose

• SDSS Technical Community

• SDSS Research History

• SDSS Research Priorities

• Overview of SDSS Tasks

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SDSS Research Program Purpose

• To address safety, performance, and technology issues in the areas of:– Software– Complex electronic hardware– Digital systems

• SDSS research supports the policy and guidance initiatives of the FAA

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SDSS Technical Community Research

Group (TCRG)• Leader: Leanna Rierson,

CSTA for Aircraft Computer Software• Sponsor: Barbara Lingberg• Program Manager: Chuck Kilgore• Members:

• Will Struck• Jorge Castillo• Robin Sova• Gary Horan• Brenda Ocker• Dennis Wallace

• John Lewis • Jim Treacy• Tony Lambregts• Tom Kraft• Larry Bessette• Steve VanTrees

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SDSS Research History

• Past Research in the Areas of:– Modified Condition/Decision Coverage (MC/DC)– Service History– COTS Software– COTS Hardware– COTS RTOS– Structural Coverage of Object-oriented

Software

• See FAA Software Website for Reports:– http://av-info.faa.gov/software

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SDSS TaskPriorities (as of Sept 2002) and Activation Status

Status Priority TaskDone 1 COTS software and component protectionFY03 2 Microprocessor evaluationsFY03 3 Object oriented technology 4 Complex electronic hardware case study

FY03 5 Semiconductor wearout effects $$ 6 Databus evaluation criteria $$ 7 Structural coverage at the object code level FY03 8 COTS component integration (follow-on to 1

above) 9 Software verification tools assessment

$$ 10 Safety engineering in softwareLegend

-In Work FY03 -Start in FY03 $$ -Start in FY04+ Done -Complete

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Status Priority TaskDone 11 Augmented manual control (fly-by-wire/light) 12 Ethernet as an aviation databus (related to 1, 6, 8, 22)$$ 13 Adaptive flight controls for general aviation$$ 14 Requirements engineering management$$ 15 Advanced guidance & control system functional design$$ 16 Tool qualification of complex electronic hardware 17 Software development tools assessment$$ 18 Flight critical systems design assurance 19 Real-time scheduling analysis$$ 20 Accelerated life qualification methods

Legend -In Work FY03 -Start in FY03 $$ -Start in FY04+ Done -Complete

SDSS Task Priorities and Activation Status (cont)

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Status Priority Task $$ 21 Avionics computer resource issues $$ 22 Wrappers with COTS software (follow-on to 1, 8

above)$$ 23 Local area networks onboard aircraft 24 Software service history case study 25 COTS ground systems verification$$ 26 Criteria for burn-in testing$$ 27 Environmental qualification of electronic

components$$ 28 Transfer of aviation data on the internet$$ 29 Software service history and reliability models

Legend -In Work FY03 -Start in FY03 $$ -Start in FY04+ Done -Complete

SDSS Task Priorities and Activation Status (cont)

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Task Categories COTS-Related Verification Complex Hardware Complex Hardware Environment Databus Flight Controls IMA-Related Software Tools Service History

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COTS-Related Tasks

PriorityPriority TaskTask 1 COTS Software and Component

Protection

2 Microprocessor Evaluations

8 COTS Component Integration

22 Wrappers with COTS Software

25 COTS Ground Systems Verification

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Verification Tasks

PriorityPriority TaskTask 3 Object Oriented Technology

7 Structural Coverage at the Object Code Level

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Complex Hardware Tasks

PriorityPriority TaskTask 4 Complex Electronic Hardware Case Study

5 Semiconductor Wearout Effects

16 Tool Qualification of Complex Electronic Hardware

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Complex Hardware Environment Tasks

PriorityPriority TaskTask20 Accelerated Life Qualification Methods

26 Criteria for Burn-in Testing

27 Environmental Qualification of Electronic

Components

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Data / Databus Tasks

PriorityPriority TaskTask

6 Databus Evaluation Criteria

12 Ethernet as an Aviation Databus

23 Local Area Networks (LANs) onboard Aircraft

28 Transfer of Aviation Data on the Internet

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Flight Control Tasks

PriorityPriority TaskTask11 Augmented Manual Control

13 Adaptive Flight Controls for General Aviation

15 Advanced Guidance & Control System Functional

Design

18 Flight Critical Systems Design Assurance

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IMA-Related Tasks

PriorityPriority TaskTask10 Safety Engineering in Software

14 Requirements Engineering Management

19 Real Time Scheduling Analysis

21 Avionics Computer Resource Issues

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Software Tools Tasks

PriorityPriority TaskTask9* Software Verification Tools

Assessment

17 Software Development Tools Assessment

*AIO Funded 1st Year

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Software Service History Tasks

PriorityPriority TaskTask24 Software Service History Case Study

29 Software Service History and Reliability Models

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Research Affiliations

• NASA’s Aviation Safety Program

• Aerospace Vehicle Systems Institute (AVSI)

• Individual Companies• Universities

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Potential IT and ISS Task Collaboration

1 COTS software and component protection

6 Databus evaluation criteria 8 COTS component integration 12 Ethernet as an aviation databus 22 Wrappers with COTS software 23 Local area networks onboard aircraft 25 COTS ground systems verification 28 Transfer of aviation data on the internet

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More Information

• See FAA software website for research reports – http://av-info.faa.gov/software

• Contacts for detailed task information– Barbara.Lingberg@faa.gov or

Leanna.Rierson@faa.gov

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Background Slides

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COTS-Related Tasks (1, 2, 8, 22, & 25)

• Tasks 1 & 8: Evaluate COTS operating systems (OS), integration techniques, and protections schemes. Focus on RTOS integration.

• Task 2: Develop criteria for new microprocessor technology.

• Task 22: Investigate use of wrappers for protecting against problems in COTS components.

• Task 25: Evaluate COTS issues in support of health-usage monitoring system (HUMS) (e.g., safety, security, & integrity).

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Verification Tasks (3, 7 & 9)

• Task 3 - Identify and address object-oriented issues in airborne software. To date research has focused on structural coverage. New task will focus on data and control coupling.

• Task 7 - Determine if structural coverage (MC/DC in particular) at the object code level is a feasible alternate to the source code level.

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Complex Hardware Tasks(4, 5, & 16)

• Task 4 – Perform a case study using RTCA/DO-254. On-going with NASA Langley:– Designed a field-programmable gate array

(FPGA) using RTCA/DO-254 (SPIDER).– Data will be used to support FAA training and

to identify areas where clarification is needed.• Task 5 – Identify and address effects of

semiconductor wearout.• Task 16 – Develop criteria for accepting tool

experience and evaluating accuracy (for tools used in complex hardware design or verification).

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Complex Hardware Environment Tasks

(20, 26, & 27)• Task 20 (Accelerated life qualification) –

Develop methods to analyze and test devices in order to establish life limits for the equipment, if necessary.

• Task 26 (Burn-in testing) – Develop burn-in testing criteria for critical electronic equipment.

• Task 27 (Environmental qualification) – Develop methods to determine reliability of components, when installed in more severe environment than originally designed for.

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Data / Databus Tasks (6, 12, 23, & 28)

• Task 6 – Evaluate a number of databuses and develop criteria for evaluation. Driven by the biz-jet architectures.

• Task 12 – Identify safety issues with Ethernet and address them. Driven by the large transport architectures.

• Task 23 - Identify and address safety concerns regarding networks used for loading flight critical data and serving passengers.

• Task 28 (transfer of data on internet) - Evaluate safety and security issues of transferring flight critical data via internet.

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Flight Control Tasks(11, 13, 15, & 18)

• Task 11 – Identify guidance materials for fly-by-wire systems

• Task 13 – Develop and implement nonlinear adaptive control concepts for general aviation aircraft

• Task 15 - Identify guidance materials for advanced guidance and flight control systems

• Task 18 - Identify guidance materials for flight critical systems architecture design assurance

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IMA-Related Tasks(10, 14, 19, & 21)

• Task 10 (safety engineering) - Evaluate the safety assessment processes and their applicability in software assurance.

• Task 14 - Identify techniques and practices for management of overall system requirements. Particularly, focused on complex, integrated avionics, with multiple developers.

• Task 19 - Identify and address safety issues of real-time schedulers.

• Task 21 - Identify IMA issues and propose solutions for safe implementation. Focuses on the integration aspects of IMA.

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Software Tools Tasks (9 & 17)

• Task 9 - Identify software verification tool qualification issues and propose solutions to help cert authorities & applicants. Focus is on structural coverage tools.

• Task 17 - Identify software development tool qualification issues and propose solutions to help cert authorities & applicants.

RTCA DO-178B

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Software Service History Tasks

(24 & 29)

• Task 24 - Document criteria for applying software service history based on an actual project and using previously-developed handbook

• Task 29 - Consider use of software service history & reliability models.