REG NASA-LLIS-1177--2001 Lessons Learned - International Space Station (ISS) Computer Hardware-Software Multiplexer-Demultiplexer (MDM) Central Processor Unit (CPU).pdf

1、Lessons Learned Entry: 1177Lesson Info:a71 Lesson Number: 1177a71 Lesson Date: 2001-02-01a71 Submitting Organization: HQa71 Submitted by: David M. LengyelSubject: International Space Station (ISS)/Computer Hardware-Software/Multiplexer-Demultiplexer (MDM) Central Processor Unit (CPU) Description of

2、Driving Event: International Space Station (ISS) Multiplexer-Demultiplexer (MDM) Central Processor Unit (CPU) Utilization Design LimitLesson(s) Learned: The MDMs on the ISS are already at the 65 percent utilization design limit of their central processor unit (CPU) with four major software releases

3、still to come. There is no identified method for accommodating the inevitable increasing demands on the CPU.Recommendation(s): Proceed expeditiously to upgrade the MDM computer system.Evidence of Recurrence Control Effectiveness: Code M - Concur: Honeywell has completed a concept design of an upgrad

4、ed processor (from the Intel family) that can be used as card replacement for the CPU card in the enhanced MDM. The time from turn-on to delivery of the new cards was estimated at 24 to 30 months. The replaced enhanced CPU cards could then be used in any Standard MDM requiring additional processing

5、or memory capability. It should be noted that Boeing was able to reduce the CPU requirements for the C&C software by 20% as part of the revision 2 development. While the pressure has been relieved in the short term, the processor upgrade will continue to be worked.Documents Related to Lesson: Provid

6、ed by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N/AMission Directorate(s): a71 Exploration Systemsa71 Space Operationsa71 Aeronautics ResearchAdditional Key Phrase(s): a71 Computersa71 Configuration Managementa71 Flight Operationsa71 Information Technology

7、/Systemsa71 Policy & Planninga71 Risk Management/Assessmenta71 Softwarea71 Test & VerificationAdditional Info: Approval Info: a71 Approval Date: 2002-03-18a71 Approval Name: Bill Loewya71 Approval Organization: HQa71 Approval Phone Number: 202-358-0528Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-