[SATLUG] Average lifespan of an Adaptec SCSI card?

Brad Knowles brad at shub-internet.org
Wed Jul 22 22:24:03 CDT 2009

on 7/22/09 8:56 PM, Alan Lesmerises said:

> In the case of solid-state electronics, it has long been known that the 
> bulk of the failures occur in a pattern known as "infant mortality" (and 
> the name does come from human death studies).  That means that failures 
> occur with decreasing frequency with time, and the longer it lasts, the 
> longer it's going to last.  That being said, it they are subjected to 
> some external factor (excessive overheating, vibration, etc.), failures 
> can also be externally induced.

In my experience, it is more typically called a "bathtub curve", because 
it looks like a bathtub in profile -- high on one end, low in the 
middle, and then climbing back to high again at the end.

Planned obsolescence is a very real principle that is used by most 
companies these days when they design their products, such that they 
really do tend to start failing a little after the warranty has expired. 
  Yes, the Engineers have gotten good enough with their design tradeoffs 
and other techniques, that they can come statistically quite close to 
whatever warranty policies that the business types want to implement.

Of course, there are plenty of other factors to be considered, but that 
does describe what I've seen as an overall trend.

> So, without having specific data to refer to, I'd be inclined to say 
> that 6 years isn't bad amount of service life to get out of that card, 
> but the question of whether the other ones are about to fail is much 
> more difficult to answer.

Consider this -- for the last several generations, designs have been 
getting generationally better roughly every 18 months, with the cycles 
slowly getting shorter (so that we're getting closer to 12 month 

In that paradigm, the SCSI card that lasted six years equates to a 
hardware device that has lived through four generations.  Now, when you 
are the fourth generation in your family (and in your 80s, because human 
generations are about twenty years), tell me how likely you are to be 
working well?

It's had a good life.  Time to give it a good burial and go buy a 

If you want exactly the same device, or even something just compatible, 
you're going to have a hard time finding it since most of those will 
probably have died or been recycled already.

You may even end up having to completely replace the entire computer 
system in question, because you just can't find decent hardware that is 
compatible with equipment that old.

Brad Knowles <brad at shub-internet.org>
LinkedIn Profile: <http://tinyurl.com/y8kpxu>

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