Your question is a bit confusing. Are you looking for volatile or
non-volatile memory?
PC RAM is of course volatile and dynamic - you would need to refresh the
data quite often, I don't think that's a practical option in the PIC world,
but you didn't mention what you're using.
You mention "low-volume" and "rugged", both of which are vague enough to
make any advice possibly meaningless.

Various versions of SD cards can be quite rugged - probably not "artillery
shell" rugged, but certainly "automotive" rugged. (GoPro cameras?) And
depends more on the connector used. For more robust mechanics in low volume
I would start with a gob of hot-melt glue on and around the card after
install (micro SD better here because of low mass). Other option is no
connector at all, solder wires directly to the card fingers then bond the
card to your product with a suitable adhesive. May complicate retrieving
the data, but in "low volume" it may be an option

Either of these options require you to manage the file system which may or
may not be an issue.
There are also several commercially available "dataloggers" that basically
have some flash memory (SD card slot usually) and a processor preprogrammed
to allow you to send it the data via serial. It may be helpful in a low
volume situation. I've seen some of those used in model rocketry, so
there's one measure of "rugged". Here's a couple links from a cursory
search:
https://www.adafruit.com/product/1141
https://www.sparkfun.com/products/12772

There's also the FTDI Vinculum parts that do something very similar but use
a USB flash drive:
http://www.mouser.com/new/ftdi/ftdivinculum2/
Options from bare chips to breadboardable modules to panel mountable fully
enclosed units.

One of the other emails mentions "wear leveling" - absolutely critical in
long life products. Completely meaningless for some short lived
applications. I've done datalogging during development projects that's only
ever had to be written a couple times - didn't bother with any of the
"normal" file system niceties, just spew data into the chip and parse it
back out later with PC side tools.

The other option worth mentioning - can you upload the data realtime with
some type of telemetry? I've recently been digging into WiFi modules and
it's been an eye opening experience. If you're in an environment where
wireless of some type is an option, it wouldn't be "too much work" to
uplink the data to a more capable system. WiFi is almost trivial to
implement nowadays, but dozens of other wireless options exist with various
benefits and drawbacks.


Hope this helps - if it doesn't, we may be able to do better if we better
understand your application.

-Denny
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.