Maybe I should have rephrased it. The problems I see may not be the result of
write access to the card. It could have other explanations.
I have done a lot of testing though with solid setups (ext2 rather than
ext3/ext4, read-only setups with AUFS and ram, etc). The updating part in my
experience kills it. However it could be that taking it in and out frequently
(daily) for months causes the problem. It could also be that maybe data isn't
being properly flushed to the disk on shut down or something similar.
However that said I can think of other scenarios where lots of data does
appear to have killed the USB flash sticks. I'll give you examples. I used
the Trisquel flash drive to write bootable ISO images to it. I got maybe 5-10
images written to it before I started seeing disk errors. In that situation I
didn't take the drive in and out though more than maybe a dozen times. Now
these are cheap flash drives and not using SLC or anything like that. And it
is pretty well known that the cheap stuff doesn't last.
However I have seen similar results with highly rated "never fails" MLC Micro
SD cards that run significantly higher. I was testing with 16GB cards.
I've also seen problems with 32GB SDHC cards with SLC.
For those who don't know SLC is a higher quality flash which allows more
writes to it before failing.
Some of the setups I've had included real world testing with things like
raid: software raid'd that is between two 32GB SLC SDHC cards that used USB
card readers. Ultimately the one drive failed in a rather short time. And
yes- this was with a properly setup card. It was used in a read-only setup
(and verified) except during the update process. The only other time it got
written to were when files were saved to a second partition although this 2nd
partition was not for swap. It was for data and did not hold a home directory
and didn't get mounted until I manually mounted it. No data would have been
written to it without having manually mounted it and then going to save a
file.
And the reason for the raid'ing of SDHC cards and using SLC had to do with
the fact flash is terribly unreliable in the real world.
Now- I'm not trying to dispute your results. There could be an explanation
for this that has nothing to do with the read/write or the connection. I
haven't figured it out and am doubtful though given all the evidence I've
seen.
I think when SD/Micro SDHDC/etc cards are used to store files infrequently or
used in cameras/phones/etc they tend to last. That has been my experience and
what I've seen from reading well reviewed cards with hundreds of people
reviewing the same product.
More data would be useful. My data comes from years and years and years of
testing. I'm actually working on testing a type of Mini non-removable SSD
card that fits into the Mini PCIe card slot (If I recall correctly, this has
been a project that has spanned 10+ years which I infrequently gets to work
on, these slots though have to support a USB function to work with the Mini
PCIe SSD cards).
I've tried compact flash using adapters to IDE adapters in the past. I always
seemed to run into problems with the adapters though. You can get an OS
loaded on them, it boots, and shortly thereafter fails. I haven't done that
though in 10+ years probably though. I last tested that with a 200Mgz Pentium
system.
