HP-48 FRAM Cards

[snrowe]

Hi David,

I researched FRAM about a year ago and the information I came across claimed FRAM has a destructive read which is followed by a write to write the data back after reading. I don't have all the references handy as I read up on it a while ago, but the article I posted above claims FRAM is destructive read.

If you have information to the contrary I'd love to hear it as I'd like to put my cards back in action without worrying about wearing out the memory from running programs off the card.

(07-23-2016 12:46 AM)Dave Frederickson Wrote:  Thanks, Matthias, for those FRAM articles. The first article states that FRAM is good for >10^14 write cycles or >150,000 years of continuous data logging.

For FRAM71 owners, the chip used, a Cypress FM22L16, is good for more than a trillion read/write cycles and data retention is rated at 151 years (Really! Had to eek out that extra year to beat the competition with only 150 years.).

So FRAM's disadvantages are higher cost, lower densities than flash, and storage capacity limitations (according to Wikipedia).

(07-23-2016 12:03 AM)snrowe Wrote:  Cons:
-Fram memory has a destructive read mechanism, meaning it can only be read a finite amount of times ~(10^14) before the memory is trash.

Incorrect! A destructive read mechanism means that the data is lost when read and must be followed by a write operation to restore the data, like magnetic core memory. This has nothing to do with endurance.

Dave