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Hello fellow HP enthusiasts.

I know that the first HP calculator with Continuous Memory was the HP-25C. However, does anyone know if this was the first calculator to ever to have continuous (aka constant) memory? Or did TI or another calculator manufacturer introduce this featuer prior to the HP-25C?

Thanks for everyone's input.


If you're not concerned about the exact implementation, the HP-9100 had memory that was actually far more "continuous" than the HP-25C. I should add a note on that to the timeline.

Dave is right. The HP 9100 used core memory and it would hold it's contents even with no power. I have one and it's quite strange to turn it on and see everything still there. BTW the HP9100 dates from 1968.


Thanks for your responses.

But when was continuous memory introduced on a handheld calculator?


I'm not sure of the timeline (and who was first), but I know that at roughly the same time TI came out with the continuous version of the ti-58 I think. (This was the non-card programmable version of the ti-59.)

Shortly after, HP came out with the HP-29C which I bought. (And then I bought the HP-41C and so on...)