Wow, sounds like the problem I had too. If your PCMCIA card is a flash disk,
then my guess is that you need a "special driver" from the disk manufacturer
which limits the current draw of the PCMCIA device.
I believe that what's happening is this: Flash devices require a lot of current
to perform read and particularly write operations. When the Zoomer batteries
are getting weak, but not so weak that you get a "low battery" warning, the
instantaneous current draw of the flash device can cause the battery voltage to
drop below the threshhold at which the Zoomer can continue to operate -- and so
it crashes. Since it's not even a graceful crash, the file which was being
written is likely to be left in a corrupt state.
The special driver limits instantaneous current draw, at the expense of speed I
suppose, and appears to fix the problem. I used to corrupt a file about once
per month -- each time my Zoomer batteries were getting low -- and after having
installed a new driver from SunDisk I've had no problems.
There are a couple of ways you can try to recover your file, but neither are
terribly satisfying. Geoworks Ensemble comes with a program called "salvage",
which you can use to extract text from the corrupt datebook. Similarly, you can
use the "strings" command on a UNIX system and extract text. The problem is
that you get only the text of datebook items, not the date and time, but it may
be helpful if you're reconstructing a datebook.
I'd recommend that you put the new datebook and any other frequently-accessed
files on your internal memory and not on the flash device until you've gotten
and installed that special driver from SunDisk (or whoever made your's). Even
with the driver, I still keep frequently-accessed files on internal memory
because it's a little faster than flash.
-- -Brian Smithson brian@grot.starconn.com