On 12/11/14, 6:14 AM, Brian Lloyd wrote:
On Thursday, December 11, 2014, Jim Lux <jim...@earthlink.net> wrote:
Ah, but will the exact same single board computer be available for
replacement in 5 years?
Most likely not. These days I can't imagine a manufacturer making the same
SBC or mobo board for more than a year. If you consider BBB to be the
logical continuance of the original beagle board then it is going on two
years but is at rev C.
Or will it be Rev F instead of Rev B, with "just a few tweaks to improve
performance", but also enough that it's not "drop the image on it and run"
What about 10 years?
15?
If that is an issue, buy a spare and keep it in the same box with each
running one. Heck, buy two spares.
I'm not sure that's a valid approach.. because eventually, the spares
fail, or there's some crippling problem (year 2000 problems hardcoded in
something, etc)
At JPL, we are somewhat cursed by the fact that we don't depreciate our
test equipment and computers. It's expensed in the year you buy it, and
then it is essentially free forever (subject to calibration and
maintenance costs).
Therefore we have a lot of really old equipment around, and new systems
are designed and built incorporating the old equipment. But when the
last unit of that old model fails, now you have to update everything and
jump multiple generations at one time, which is difficult. You've got a
lot of learned history and designs that rely on idiosyncracies of a
particular model (e.g. the 8663A, which happens to do phase continuous
sweeping and can be phase modulated directly).
And now, your venerable 8663 fails.
The new replacement model (e.g. the E8663B) is functionally quite
similar, has all the same specs (maybe even better in some cases), but,
oops, it doesn't do phase continuous sweeping (because the synthesis
chain is different).
Rather than figure out how to solve the need with the newer gear, this
leads to a scrounge fest. You get the institutional inventory and
surplus list out and start calling up people who have seem to have
another 8663A that hopefully they're not using and/or that it actually
works.
We've got stacks of dead 8663s sitting around, in, I think, the forlorn
hope that someone will be able to cannibalize them for repair parts.
The problem is even worse with PCs, because the support cycle time is
shorter.
The wailing, gnashing of teeth, and pulling of hair when NT 4.0 and
later WinXP was declared OS non grata was amazing. Data acquisition
systems, lab controllers, etc. all running WinXP and connected to the
network as part of their function. Upgrading your software from NT to
WinXP to Vista then to 7 then to 8 isn't as painful as jumping from NT to 8.
Linux isn't a whole lot better. If you have a system you cobbled
together in 2004 that was tied, say, to the typical audio system of the
time, odds are that you're in for a real challenge to drop it into a
modern distro with modern motherboard hardware. Which version of glibc?
OSS audio? parallel port drivers? Oh, your new mobo doesn't HAVE a
parallel printer port?
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