Calculators that allow direct operations on data stored on persistent storage?

[Carsen]

I have no experience with the SD card on a 50g yet so I can't help you there. However, there is a function on the HP 50g that does what you are looking for.

Key in 97.01 [ENTER] then key in MENU [ENTER]. You will be warped to the data menu in the STATS soft menu. Next type in another entry to your record in a matrix format via matrix writer or with the matrix brackets. Next press the ∑+ soft label on the F1 key. This will add another entry to the data in ∑DAT without recalling the contents. Test it out with a little bit of data.

Unfortunately for you, your data seems to be in lists. So transferring to this method is going to be a pain. Also, the data has to be in a variable called ∑DAT which is inconvenient. Plus, I don't know if this can work with data stored on an SD card. Still, this method is work mentioning because maybe it can work with an SD card.

Do you understand what I'm explaining here?