Tool Selection
When selecting a tool to assist in achieving DO-178B compliance, the following criteria should be considered:
- Does the tool enable analysis for all Structural Coverage Analysis requirements as laid out in section 6.4.4.2 of the standard?
- Is there tool availability for a wide range of programming languages?
- Has the tool been utilised in this manner successfully already?
- Will the supplier assist in tool qualification?
- Is the supplier both flexible and extensive enough to meet changing requirements?
- Is the tool easy to use?
The LDRA answer to all of the above questions is YES.
Flexible Tool Support
DO-178B is evolving in response to experience gained by the FAA when applying the standard to real-world applications. LDRA has the skills and expertise to adapt the LDRA tool suite to meet these changing requirements and is committed to providing a powerful tool suite that will verify compliance with the standard both now, and in the future.
For example the FAA is currently requesting coverage information on combinations of constructs that only the LDRA tool suite can measure. In addition DO-178B may require coverage of implied XOR in the C language. LDRA is already committed to existing customers to meet this requirement if this is the case.
DO-178B Structural Coverage Analysis Requirements
Following is the pertinent extract from DO-178B:
6.4.4.2 Structural Coverage Analysis
The objective of this analysis is to determine which code structure was not exercised by the requirements-based test procedures. The requirements-based test cases may not have completely exercised the code structure, so structural coverage analysis is performed and additional verification produced to provide structural coverage. Guidance includes:
The analysis should confirm the degree of structural coverage appropriate to the software level.
The structural coverage analysis should normally be performed on the source code. If DO-178B Level A verification is required then additional analysis must be undertaken on the object code to verify the correctness of the compiler-generated code sequences. Both of these analyses may be performed with the LDRA tool suite.
The analysis should confirm data coupling and control coupling between the code components.
These requirements are summarised as follows:
| Item |
Description |
DO-178B Ref. No. |
DO-178B Level A |
DO-178B Level B |
DO-178B Level C |
| 5 |
MC/DC is achieved |
6.4.4.2 |
Satisfied with Independence |
Not Required |
Not Required |
| 6 |
Decision Coverage is satisfied |
6.4.4.2.a
6.4.4.2.b |
Satisfied with Independence |
Satisfied with Independence |
Not Required |
| 7 |
Statement Coverage is satisfied |
6.4.4.2.a
6.4.4.2.b |
Satisfied with Independence |
Satisfied with Independence |
Satisfied |
| 8 |
Data Coupling and Control Coupling is achieved |
6.4.4.2.c |
Satisfied with Independence |
Satisfied with Independence |
Satisfied |
Note: Items 5, 6, 7 and 8 are not required for DO-178B Level D.
The LDRA Tool Suite DO-178B Coverage Measures The LDRA tool suite delivers the coverage measurement criterion as laid down in DO-178B:
DO-178B Level A Measurement:
- Modified Condition Decision Coverage (MC/DC)
- Branch/Decision Coverage (TER2)
- Statement Coverage (TER1)
DO-178B Level B Measurement:
- Branch/Decision Coverage (TER2)
- Statement Coverage (TER1)
DO-178B Level C Measurement:
- Statement Coverage (TER1)
Other Coverage Measures:
- LCSAJ Coverage (TER3)
- Branch Condition Coverage (BCC)
- Branch Condition Combination Coverage (BCCC)
The LDRA tool suite is currently the only analysis tool to offer such comprehensive assistance in meeting DO-178B.
Note also that there is currently no other tool that provides the code analysis capabilities required to test Assembler code to DO-178B standards.
Is the tool suite easy to use?
The tool suite’s ease of use is a key issue when incorporating it into project procedures. The LDRA tool suite has been specifically enhanced to enable simple measurement of conformance to the various levels of DO-178B. Reports are specifically tailored to give users DO-178B information quickly and concisely, speeding up the testing procedure. Reports can be produced in either ASCII or HTML. Either format can be easily incorporated into a Word processor or DTP system. HTML has the added advantage of links and the ability to publish on the Internet or an intranet.
Proven Track Record in RTCA/DO-178B Certification
The LDRA tool suite is being utilised by companies around the world to meet RTCA/DO-178B and other avionics standards. A cross-section of clients currently utilising the LDRA tool suite include:
ADA India
Airbus France
Bell Helicopters Textron USA
Boeing USA
Dunlop Aviation Coventry
Fiat Avio Italy
Honeywell USA
Lockheed Martin Aeronautics Co USA
Northrop Grumman USA
Rolls-Royce Derby
SENER Spain
Smiths Aerospace
TEC-Masters USA
Thales Avionics France
TRW USA
Ultra Electronics High Wycombe
Westland Helicopters Yeovil
Obtaining Further Information
For further information on DO-178B Certification complete the LDRA reply form or email .
Details on how to purchase the DO-178B standard can be found on the RTCA web site: www.rtca.org.
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