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Forum: Reliability & Maintainability Questions and Answers

Topic: Reliability & Maintainability Questions and Answers

Topic Posted by: Reliability & Maintainability Forum (src_forum@alionscience.com )
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998

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Original Message:

Posted by: Ian
Date posted: Wed Nov 21 9:23:44 US/Eastern 2001
Subject: Memory MTBF's
Message:
Can anybody tell me what is a realistic MTBF value for standard 128Mb and 256 Mb of RAM type memory. Thanks in advance


Reply:

Subject: Memory MTBF's
Reply Posted by: Paul Jaworski (pjaworski@alionscience.com )
Organization: Reliability Analysis center
Date Posted: Wed Nov 21 17:05:06 US/Eastern 2001
Message:

Ian;

 Hear are the failure rates for Field Failure data out of The Reliability Analysis Centers, Electronic Parts Reliability Data (EPRD-97).
 The Failure Rates have been converted to MTBF by years and hours.
 However at this time we have no way to differentiate between 128Mb and 256Mb.
 Some of the manufactures data books do present MTBFs.
 
 
 Part            Qual    App.    Failure      (MTBF)   (MTBF)
 Description     Level   Env.    rate/E*6       Hrs      Yrs
 
 EPRD-97 pg 2-115
 IC, Plastic, Memory                0.1393         7,178,750.9      819.5
 RAM, (Summary)     Commercial          0.0852    11,737,089.2    1,339.9
 EPRD-97 pg 2-183
 IC, Unknown, Memory,               0.1795         5,571,030.6      636.0
 RAM, (Summary)     Commercial GBC      0.1511     6,618,133.7      755.5
 ________________________________________________________________________
 Total Summary
 Unknown Qual levels                0.3188         3,136,762.9      358.1
 Commercial Qual levels                 0.2363     4,231,908.6      483.1
 
 GBC = Ground Benign Commercial
 

Reply:

Subject: failure rates
Reply Posted by: don miller (dmiller897@aol.com )
Date Posted: Sat Dec 8 19:11:22 US/Eastern 2001
Message:
I had hope that these type of question would vanish. I retired 5 years ago from Boeing. 30 +years searching for a random failure never found one. There is no data which can be related to random failures in any hardware. Failure can an will occur. Virtually (sp) because of design problems, manufactoring pro. If a so called random failure has ever occured, how would you expect some to record the time the commponent operated. Think about ever morning when your mind is clear. It will take about 2 years to clear up your thinking. dmiller897@aol.com


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