fx-9860gii-2 brief introduction

[Hlib]

(11-24-2019 07:52 PM)Mjim Wrote:  Hlib, did you happen to record the part number of the flash chip used in your fx-9860GII during the tear down?

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.