fx-9860gii-2 brief introduction

[Mjim]

(11-24-2019 10:55 PM)Hlib Wrote:  No, I didn`t write down the flash chip number. Getting to it without damaging the loops is not easy, so I did not disassemble the calculator completely.
Once upon a time I researched this issue in connection with other devices from CASIO. They are very serious about the issue of data saving. In particular, cooperating with the company SunLight, which dealt with this problem, CASIO introduced advanced developments in the AFX-2.0 and PV-250/460/660 back in the late 90s. In AFX-2.0/2.0+, for example, data of type List for some reason at saving were duplicated also in hidden flash-RAM area. All manipulations with them affected reading/writing from flash, which greatly slowed down the speed of the calculator in programs, but it had 146KB of RAM available to the user. And this is much more cycles than when you turn off and turn on modern calculators with flash-RAM. However, these worked for me for more than 15 years and remained serviceable. Now these technologies have become more reliable and cheaper. There is no cause for concern, but sometimes they deceive us. My hp-39gii could not withstand a few thousand cycles during a year. It often lost all the data from the RAM, then stopped saving them at all when turned off, although it had a flash chip with a capacity of several tens of megabytes. Very strange.

I didn't realize that the flash chip was hidden on the fx-9860GII. On the fx-9750GII it is easily visible just from opening the case. As someone that has already broken the connector loop between the motherboard and keyboard, I can fully understand not wanting to risk that!

I managed to find a version 2 of the fx-9750GII which uses a different flash chip here:
https://tiplanet.org/forum/gallery/image...ge_id=8422 and I think this may be the datasheet for the flash chip (It seems to be 100,000 cycles as well): http://static6.arrow.com/aropdfconversio...es-70g.pdf

Fascinating stuff about Casio and SunLight partnering up to deal with data storage. Would love to hear more, but I'll see if I can't exercise my Google skills to look into this so I don't take more of your time. Appreciate the extra info, thanks!