Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!pasteur!helios.ee.lbl.gov!nosc!peanuts.nosc.mil!dennis
From: dennis@peanuts.nosc.mil (Dennis Cottel)
Newsgroups: comp.sys.apollo
Subject: Re: MTBFs of Apollos
Message-ID: <1075@nosc.NOSC.MIL>
Date: 1 May 89 19:04:37 GMT
References: <5105@ncrwic.Wichita.NCR.COM> <639@idacom.UUCP>
Sender: nobody@nosc.NOSC.MIL
Reply-To: dennis@peanuts.nosc.mil.UUCP (Dennis Cottel)
Organization: Naval Ocean Systems Center, San Diego
Lines: 19

In article <639@idacom.UUCP> danny@idacom.UUCP (Danny Wilson) writes:
>BTW, according to reliability theory, MTBF (mean time Between failures)
>is not as meaningful as MTTF (Mean time to failure).
>             ---------------          ------------------
>             |<-- MTTF --->|<- MTTR ->|
>     --------|             |----------|
>              <------ MTBF ---------->
>Therefore the MTBF actually should include the MTTR (mean time 
>to repair).

We have the standard Apollo maintenance contract, and our mean time to
repair hardware problems has been measured in hours.  For example,
last week I made a call to the Apollo hotline at 0930 and the node was
repaired by 1115.  This is typical of the service we have been
getting.  The CE (Chris Evans, San Diego office) even apologized for
being late!
                                                  --Dennis
	Dennis Cottel  Naval Ocean Systems Center, San Diego, CA  92152
	(619) 553-1645      dennis@nosc.MIL      sdcsvax!noscvax!dennis