bannera

Book A.
Introduction

Book B.
7150 Requirements Guidance

Book C.
Topics

Tools,
References, & Terms

SPAN
(NASA Only)

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SWE-139 - Shall Statements

1. Requirements

6.3.4 Centers and projects shall fully comply with the "shall" statements in this NPR that are marked with an "X" in Appendix D consistent with their software classification.

1.1 Notes

If the requirement is marked with a "SO" in appendix D, the project is required to meet the requirement to the extent necessary to satisfy the safety critical aspects of the software.

1.2 Applicability Across Classes

This requirement applies to all classes and safety criticalities.

Class

  A_SC 

A_NSC

  B_SC 

B_NSC

  C_SC 

C_NSC

  D_SC 

D_NSC

  E_SC 

E_NSC

     F      

     G      

     H      

Applicable?

   

   

   

   

   

   

   

   

   

   

   

   

   

Key:    A_SC = Class A Software, Safety Critical | A_NSC = Class A Software, Not Safety Critical | ... | - Applicable | - Not Applicable
X - Applicable with details, read above for more | P(C) - P(Center), follow center requirements or procedures

2. Rationale

Earlier versions of NPR 7150.2, NASA Software Engineering Requirements, assumed that readers would accept requirements marked by an "X" in Appendix D as required activities. Experience with the baseline version of this NPR, i.e., NPR 7150.2, showed that this assumption was not universally confirmed.

NPR 7150.2 was written to include the explicit statement in the requirement that full compliance with the requirement is necessary for those entries assigned an "X" in Appendix D.

The purpose of the Requirements Mapping Matrix in NPR 7150.2 is to essentially pre-tailor out requirements for less critical software systems, e.g., while Class A software has 111 invoked requirements for projects, Class H has only 16. The purpose of the "X" label is to clarify the intent of NPR 7150.2 and to preclude any alternate interpretation of invoked requirements.

3. Guidance

This requirement affirms that designated Center and project personnel are to satisfy all invoked requirements of this NPR. The note further affirms that at least the safety aspects of an NPR requirement are to be satisfied if the requirement is simply labeled in NPR 7150.2, Appendix D, as "safety only" (SO).

This requirement makes a positive statement that the invoked requirement is to be fulfilled by the SWE's responsible party (indicated by the 4th column in the same Appendix D, Requirements Mapping Matrix).

Inherently, it affirms that fulfillment of requirements marked with an "X" is the rule for specific NASA software classifications.

Deviations, waivers, and tailoring of the requirements of NPR 7150.2 are to follow the approved processes for requirements management. (See SWE-120 and SWE-140.)

4. Small Projects

No additional guidance is available for small projects. The community of practice is encouraged to submit guidance candidates for this paragraph.

5. Resources

5.1 Tools

Tools to aid in compliance with this SWE, if any, may be found in the Tools Library in the NASA Engineering Network (NEN).

NASA users find this in the Tools Library in the Software Processes Across NASA (SPAN) site of the Software Engineering Community in NEN.

The list is informational only and does not represent an “approved tool list”, nor does it represent an endorsement of any particular tool. The purpose is to provide examples of tools being used across the Agency and to help projects and centers decide what tools to consider.

6. Lessons Learned

There are currently no Lessons Learned identified for this requirement.

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