>
> To date, Flash Memory has not been considered to be
> "archival" by any means. In fact, within the telecom
> industry it has already been proven to be, uh, less than
> stable. I understand and agree with what Wayne is saying,
> but in actual practice we're experiencing failures. From what
> I'm hearing from my cohorts on the supply side--it is looking
> like about 5% of 36 months of in-service devices are
> experiencing corrupted memory. Inotherwords, one out of
> every 20 boxes is getting random failures pointing directly
> to corrupted flash memory withing three years. This 5%
> failure rate definitely coincides with our own experiences.
> What really gets one sweating is when you have a device that
> needs rebooting and it doesn't come back online because the
> programming and configuration, which is stored on flash
> memory is corrupted. Trust me, it happens more often than
> anybody wants to admit. That's why, in our own company, we
> have a pretty tough procedure to follow before we ever cycle a box.
>
The company I'm working for use ruggedised PDAs for various business
functions, they sit in a cradle in a truck most of the time so are subject
to a fair amount of vibration and temperature cycling. We have around 250
in use and we probably have to reload the software for 5 per week. The
software is on an SD card which also is used to store temporary data. We've
been using a variety of SD cards from different manufacturers and the rate
of failure doesn't seem to correlate with the manufacturer (once we weeded
out one manufacturer of particularly cheap and nasty cards). At one stage I
put a lot of "failed" cards aside and tested them with some data recovery
software (Lexar ?) which did a number of write/read cycles of the complete
media and I couldn't duplicate the problems. The current consensus seems to
be that the problems we see are related to the tough mechanical conditions
that the cards are subjected to, probably the connection between the PDA and
the SD card. This doesn't really answer any questions about how long the
data will survive on archived cards but may be related to some of the
failures we notice with this type of media in digital cameras.
...Wayne
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|