This software emulated the different processors of several classic HP calculators, enabling the user to plug the original ROM and have it running in the chosen device. The most popular among them was Nonpareil, from Eric Smith. Meanwhile, external developers had created different emulators for HP calculators. It was not a big success: improvements were not substantial, and there were some software bugs (later versions of the HP 12c Platinum have fixed all known issues) The HP12c Platinum was an example of the second alternative: they tried to make a calculator with a new processor and software, taking the opportunity to add some 'improvements'. There were three alternatives: shut down the product (the longest running and highest production product in HPs history), make a new calculator in the same box or find an emulator solution. However, time goes on and processors, memories and displays for the HP12 were no longer produced. Even with intensive use, batteries are good for at least 2 years.

It is not unusual to find examples running on the original set of batteries, 20 years after production date. However, the low speed and the fact that it did not have any I/O to monitor, made it extremely energy-conscious. Clocked at around 250 khz, less than half that of the hp 41c, the calculator is painfully slow, seen with current eyes. The model was out in the market in 1981 (now 30 years ago!), with a processora based on the 'coconut' technology (the hp 41c processor). Few people know that sometime ago HP completely changed the innards of the old HP 12c.

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