I read an article once about hard drive MTBF. The author said it was
based on the cumulative hours of operation of a whole bunch of them in a
test rig running some kind of dummy workload. So if you had 10,000 disks
in the test rig and averaged one failure every 100 hours then you had
1,000,000 hours MTBF. It's not an indicator of the lifespan of an
individual unit, and unless you have whole craploads of the devices in
operation you can't make any useful prediction based on it.
Where it could be useful is if Seagate sells you a desktop drive with
1,000,000 hour MTBF and an enterprise drive with 2,000,000 hour MTBF,
and we presume Seagate tested them the same way and was honest, then
it's evidence that you might get (on average) twice the lifespan from
the enterprise drive.
The article was not about radio equipment, but I can't see any other way
you'd arrive at a number like 40 years. If the vendor you're speaking
of had run their testing for > 4 years, then in theory the design flaw
would have come into play and their MTBF would end up being around 4
years.
-Adam
------ Original Message ------
From: "Kurt Fankhauser" <[email protected]>
To: [email protected]
Sent: 8/26/2017 11:29:44 AM
Subject: [AFMUG] Manufacturer MTBF ratings and actual lifespan of
product
Where do these MTBF ratings come from by radio manufacturers? Are they
just made up numbers the manufacturer "hopes" that the product can
achieve or is actual testing done to get to these numbers? I thought i
seen a radio once with a 90 year MTBF rating. How they hell can they
determine that? The components in the radio didn't even exist 90 years
ago.
If a radio manufacture states in the spec sheets that the radio has a
40 year MTBF rating but then also admits that after 4 years expect to
have problems due to a design flaw, what does that mean? Is the
expected MTBF rating only good in a "lab environment" under "ideal
conditions"?
Seems to me the MTBF is just marketing fluff and actually doesn't mean
crap....
