I don't think this would be such a problem. It would probably
be less of a problem if you used a PIC that can read its own
Flash memory, eg the 877, which will give you a lot of 14-bit
storage. As it's likely anything you want to display will be in
7-bit ASCII then any kind of storage location will have an 8th
bit spare for flags. As for the data location calculation, having
the data stored in groups of 16 (assuming a 16x2 LCD) would
make for a fairly easy offset and retrieval algorithm, and using
the free bits would keep all the data and action flags contained
with that 16-byte block. You could bookmark blocks as "not yet
available for display" by perhaps setting bit7 of the first byte to
indicate that the calculation has a valid result, and set some
other bit7 within the block to indicate "no data - abort display
attempt"

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics