Hi,
> in case the Nspire is stolen...is there anyway to have some security
> feature like HP, in which one needs to key in a code to use the
> calculator? TY!
Fundamentally, no, as long as there is a way to put the calculator in
such a state that it can be fixed (by repair people).
Neither the TI-Z80 series, nor the TI-68k series, nor the Nspire series
are safe from your POV: indeed, it's relatively easy to take control of
the calculator, through simple manipulations, even if it can yield data
losses.
Chances are that the HP calculators you're talking about are not safer.
Regards,
Lionel.