HP-48 FRAM Cards

[matthiaspaul]

(07-23-2016 10:56 PM)JDW Wrote:  

(07-23-2016 05:10 PM)matthiaspaul Wrote:  The point is that SSDs and flash cards are used for data storage (replacing hard disks etc.), not to replace a computer's RAM (SRAM or DRAM), where many orders more read-write-cycles will occur. ...limited life-time of the FRAM card in this configuration, but also because the other 128KB half of the calculator's memory remains SRAM - that is, the calculator would still loose its memory contents, when the batteries are exhausted. This drawback could be eliminated only by replacing the internal memory by FRAM as well...

You speak of limited life of FRAM when used as memory, then to cite the benefit of replacing memory with FRAM. :-)

Yes, it might look like a contradiction, but I was just trying to answer several potential questions at once. It all depends on the goal someone wants to achieve:

If an extremely long operational life is paramount, this rules out the idea of using an FRAM card as memory expansion in slot 1.

If, however, someone can accept a somewhat limited (but probably still long) operational life, but wants to have a calculator with persistent memory for hassle-free long-time storage of the calculator, so that he can continue calculating exactly where he left the calculator ten years earlier, he might again consider FRAM. This won't work, though, because the other part of the memory would still be battery-powered, so the calculator would have to be reset when that battery is exhausted. Ihis idea would work only after replacing the internal SRAM by FRAM as well.

This isn't an issue, however, if the FRAM card is only used for storage, as much fewer cycles will occur in this configuration. So, using an FRAM card in slot 2 sounds like a good idea and it would save the user from the ever repeating the error-prone procedure of replacing the batteries. Storing the calculator away for ten years, the user would lose the calculator's RAM contents, but not the programs and data on the FRAM card, so he would be back in "business" very soon.

Greetings,

Matthias