DataSet 6 --------- File content: - space shuttle on-board flight software FAILURE SEVERITY CLASSIFICATION - space shuttle on-board flight software RELEASE PROFILES - space shuttle on-board flight software FAILURE DATA *********************************************** * Data made available by permission from NASA * *********************************************** ======================== SEVERITY ========================== SSOF Software Severity Classification Classification approach is based on the following categories: Severity, Problem visibility to users, Assessment description and Discriminators. The definitions and discriminators are intended to convey the intent of the severity assessment categories and to allow a realistic evaluation of the potential effect of a software error. The objective is to determine the potential impact of each error if it were to occur e during a "pre-design" flight scenario. The following severity assessments apply to the Shuttle flight software as a subsystem and represent a different entity than the safety, reliability ,and quality assurance criticality rating for the entire shuttle system. SEVERITY: 1, 1N Problem visibility to users: Perceivable to user Assessment description: Severe vehicle or crew performance effects possible - usually fixed on next flight (SEV 1N are usually waived/noted) Discriminators: SEV 1 - Regardless of the probability of occurrence of the code error during an ALLOWED "operational scenario", the code error can cause loss of control, explosion, or other hazardous effect. SEV 1N - Established or reasonable procedures PRECLUDE any operational scenarios for which the error could become a failure. If unusual or unreasonable action is required to avoid failure, then the problem IS severity 1. OR the number of hardware/software system failures required to execute the code error exceeds the design requirements for the software or system. SEVERITY: 2, 2N Problem visibility to users: Perceivable to user Assessment description: Could affect ability to complete mission objectives - not a loss of vehicle or crew issue, usually fixed on next flight (SEV 2N are usually waived/noted) Discriminators: SEV 2 - Regardless of the probability of occurrence of the code error during an ALLOWED "operational scenario", the code error can cause an inability to achieve mission objectives such as: launch, mission duration, payload deployment, etc. SEV 2N - Established or reasonable procedures PRECLUDE any operational scenarios for which the error could become a failure. If unusual or unreasonable action is required to avoid failure, then the problem IS severity 2. OR the number of failures required to execute the code error exceeds the design requirements for the software system. SEVERITY: 3 Problem visibility to users: Perceivable to user, Not a safety or mission objectives issue Assessment description: No impact to safety or mission objectives - usually waived or OPS noted, includes failures that are very likely to occur, but are insignificant in result, have minimal effects on operations, or are easily controlled procedurally. Discriminators: The effects are perceivable to the user but are not severity 1 or 2. SEVERITY: 4 Problem visibility to users: Not perceivable to user when executed. Assessment description: Insignificant violation of requirements - includes input/output and display errors not detectable by human senses, includes errors only detectable by special debug processes, usually waived without OPS notes. Discriminators: Not perceivable to user when executed. of the software (Flight Operations, Training, Testing), subtle or insignificant code implementation issues which do not exactly match requirements. ==================== PROFILES ============================= Space Shuttle On-board Flight Software release profiles (January 1, 1986 - December 1, 1994). Variables - Release: release code, Date: date of release mm/dd/yy, Size: the number of new or changed lines of code (in thousands of lines) ---------------------------- Release Date Size ---------------------------- REL-A 9/14/82 584 REL-B 11/23/82 4 REL-C 6/7/83 10.6 REL-D 9/1/83 8 REL-E 12/20/83 11.4 REL-F 6/8/84 5.9 REL-G 10/5/84 12.2 REL-H 2/15/85 8.8 REL-I 12/17/85 6.6 REL-J 6/5/87 6.3 REL-K 9/11/87 3.1 REL-L 10/13/88 7 REL-M 6/29/89 12.1 REL-N 10/13/89 1.9 REL-O 6/18/90 29.4 REL-P 5/02/91 21.3 REL-Q 6/11/92 34.4 REL-R 7/15/93 24 REL-S 7/13/94 10.4 ---------------------------- ==================== FAILURES ============================= Space Shuttle On-board Flight Software failure data (January 1, 1986 - December 1, 1994). Variables - FID: failure identification number, Date: date failure was observed mm/dd/yy, Release: release in which it was introduced (see above), Severity: severity of the observed failure, UsageMode: Usage mode in which failure was observed, ObservedIn: release in which the failure was observed (releases A through R). ------------------------------------------------------------------ FID Date Release Sever- UsageMode ObservedIn ity ------------------------------------------------------------------ 1 1/8/86 REL-H 3 TESTING REL-I 2 3/14/86 REL-G 3 TESTING REL-I 3 5/29/86 REL-I 3 TESTING REL-I 4 7/30/86 REL-A 1 TESTING REL-H 5 8/14/86 REL-D 3 TESTING REL-H 6 8/25/86 REL-A 2 TESTING REL-H 7 8/29/86 REL-F 3 TRAINING REL-I 8 9/16/86 REL-G 3 TESTING REL-H 9 10/20/86 REL-A 1 TRAINING REL-I 10 12/2/86 REL-H 3 TESTING REL-H 11 1/13/87 REL-H 3 TRAINING REL-H 12 1/23/87 REL-I 3 TESTING REL-J 13 2/2/87 REL-I 3 TRAINING REL-I 14 3/4/87 REL-A 1 TRAINING REL-I 15 3/14/87 REL-A 3 TESTING REL-J 16 4/30/87 REL-A 2N TRAINING REL-I 17 5/1/87 REL-A 3 TESTING REL-H 18 7/8/87 REL-A 3 TESTING REL-K 19 9/17/87 REL-J 1 TESTING REL-J 20 9/22/87 REL-A 3 TESTING REL-J 21 10/2/87 REL-J 3 TESTING REL-J 22 12/15/87 REL-A 4 TESTING REL-J 23 1/5/88 REL-A 4 TESTING REL-K 24 1/5/88 REL-A 4 TESTING REL-K 25 1/13/88 REL-F 4 TRAINING REL-J 26 2/9/88 REL-A 4 TESTING REL-K 27 2/15/88 REL-A 4 TRAINING REL-J 28 2/18/88 REL-A 3 TESTING REL-K 29 3/21/88 REL-A 2N TESTING REL-K 30 4/7/88 REL-A 3 TESTING REL-L 31 4/9/88 REL-A 3 TESTING REL-K 32 4/9/88 REL-A 3 TESTING REL-K 33 4/11/88 REL-H 2N TESTING REL-K 34 5/17/88 REL-A 3 TESTING REL-K 35 5/19/88 REL-A 3 TESTING REL-K 36 6/21/88 REL-G 3 TESTING REL-K 37 7/8/88 REL-A 3 TESTING REL-K 38 7/12/88 REL-A 1N TRAINING REL-K 39 8/22/88 REL-A 3 TESTING REL-K 40 9/30/88 REL-A 3 TRAINING REL-K 41 10/18/88 REL-A 3 TESTING REL-K 42 11/2/88 REL-K 3 TESTING REL-K 43 12/5/88 REL-A 3 TESTING REL-K 44 2/15/89 REL-A 3 TESTING REL-M 45 4/11/89 REL-A 1N TESTING REL-M 46 4/17/89 REL-A 2 TESTING REL-L 47 4/24/89 REL-A 3 TESTING REL-M 48 5/2/89 REL-A 3 FLIGHT REL-K 49 5/11/89 REL-H 3 TESTING REL-K 50 5/19/89 REL-A 3 TESTING REL-M 51 5/19/89 REL-A 3 TESTING REL-M 52 5/31/89 REL-L 1N TESTING REL-L 53 6/5/89 REL-A 1N TRAINING REL-K 54 6/15/89 REL-A 2 TESTING REL-L 55 6/22/89 REL-A 3 TESTING REL-L 56 7/19/89 REL-G 3 TESTING REL-O 57 8/17/89 REL-A 3 TESTING REL-K 58 9/11/89 REL-K 3 TESTING REL-N 59 9/30/89 REL-A 3 TESTING REL-N 60 10/3/89 REL-L 3 TRAINING REL-L 61 10/13/89 REL-A 2N TESTING REL-O 62 11/6/89 REL-A 4 TESTING REL-M 63 11/7/89 REL-A 3 TESTING REL-O 64 11/15/89 REL-C 3 TRAINING REL-L 65 1/5/90 REL-A 3 TESTING REL-O 66 1/23/90 REL-M 3 TESTING REL-M 67 2/7/90 REL-G 3 TESTING REL-O 68 2/27/90 REL-A 3 TESTING REL-N 69 3/2/90 REL-A 3 TESTING REL-M 70 4/3/90 REL-H 3 TESTING REL-O 71 4/6/90 REL-L 1N TRAINING REL-L 72 4/18/90 REL-A 3 TESTING REL-O 73 5/8/90 REL-A 3 TRAINING REL-N 74 6/14/90 REL-A 3 TESTING REL-O 75 10/3/90 REL-O 3 TESTING REL-P 76 11/29/90 REL-A 3 TESTING REL-P 77 1/15/91 REL-O 3 TESTING REL-P 78 1/17/91 REL-A 3 TESTING REL-N 79 1/28/91 REL-O 3 TESTING REL-P 80 1/29/91 REL-G 3 TESTING REL-N 81 2/19/91 REL-E 3 TESTING REL-P 82 3/20/91 REL-O 3 TESTING REL-O 83 3/22/91 REL-O 3 TESTING REL-O 84 7/19/91 REL-O 3 TESTING REL-O 85 10/31/91 REL-P 1 TESTING REL-P 86 11/15/91 REL-O 3 TESTING REL-P 87 12/9/91 REL-A 3 TRAINING REL-O 88 2/28/92 REL-A 3 TESTING REL-O 89 8/3/92 REL-C 3 TESTING REL-R 90 10/16/92 REL-A 3 TESTING REL-R 91 12/15/92 REL-A 3 TESTING REL-R 92 7/1/93 REL-Q 2 TESTING REL-Q 93 8/1/93 REL-A 3 TESTING REL-S 94 8/19/93 REL-C 3 TESTING REL-S 95 1/6/94 REL-A 3 TESTING REL-S 96 1/13/94 REL-A 3 TESTING REL-Q 97 3/7/94 REL-A 3 TESTING REL-S 98 4/7/94 REL-A 3 TRAINING REL-Q 99 8/5/94 REL-R 3 TESTING REL-R 100 9/26/94 REL-A 1N TRAINING REL-R