Ferroelectric RAM
en.wikipedia.org
Ferroelectric RAM
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Re: Ferroelectric RAM
#2It's great stuff, but still low capacity and high cost in commercial chips. If you want to play with it, check out TI's MSP430FRxxxx microcontrollers. They have FRAM instead of Flash.
Also, there are 8-pin FRAM chips with the same pinouts as generic QSPI Flash/RAM/etc chips which you can buy today.
Again, it's still low-density and expensive, but that seems to be improving and it's fun to make applications which can re-write nonvolatile data by word rather than by page.
Re: Ferroelectric RAM
#3Not too many days ago someone was complaining about how posts about promising new technology always attracts comments warning that lab results aren't the same as commercial products: https://news.ycombinator.com/item?id=20753342. I responded that countless times in the past promising technologies had passed by without leaving a mark. Ferroelectric RAM could be the poster child for that effect - it's been around for decades but still hasn't made an impact.
Re: Ferroelectric RAM
#4“FeRAM's advantages over Flash include: lower power usage, faster write performance and a much greater maximum read/write endurance (about 10^10 to 10^14 cycles).”
This sound impressive until you get to the part where reads are destructive, and reads heavily outweigh writes in most workloads. Sounds like a pretty significant disadvantage.
Re: Ferroelectric RAM
#5“FeRAM's advantages over Flash include: lower power usage, faster write performance and a much greater maximum read/write endurance (about 10^10 to 10^14 cycles).” This sound impressive until you get to the part where reads are destructive, and reads heavily outweigh writes in most workloads. Sounds like a pretty significant disadvantage.
That's really not a problem just as it's not a problem in normal RAM. With increased speed and endurance it's a doddle to write back a value after reading with your memory controller even if you're not putting in dedicated refresh hardware. It's really all about density and cost.
Re: Ferroelectric RAM
#6“FeRAM's advantages over Flash include: lower power usage, faster write performance and a much greater maximum read/write endurance (about 10^10 to 10^14 cycles).” This sound impressive until you get to the part where reads are destructive, and reads heavily outweigh writes in most workloads. Sounds like a pretty significant disadvantage.
That's really not a problem just as it's not a problem in normal RAM. With increased speed and endurance it's a doddle to write back a value after reading with your memory controller even if you're not putting in dedicated refresh hardware. It's really all about density and cost.
Unless you lose power in the interim. Flash doesn't have that problem, and normal RAM has it so badly that we rely on Flash to store permanent data and only use DRAM as an ephemeral cache.
Re: Ferroelectric RAM
#7One of the benefits of FRAM is that you can put it through extreme radiation and still have it work afterwards. So you can put it in a medical instrument that undergoes gamma ray sterilization, and it will still not only work but also retain the data.
Re: Ferroelectric RAM
#8we make a lot of use of FRAM in our embedded systems. It's great stuff. With huge amount of write cycles it simplifies the data structures you need to store compared to page based / lowish write cycle memories.
Re: Ferroelectric RAM
#9Earlier quoted context omitted.
That's really not a problem just as it's not a problem in normal RAM. With increased speed and endurance it's a doddle to write back a value after reading with your memory controller even if you're not putting in dedicated refresh hardware. It's really all about density and cost.
Unless you lose power in the interim. Flash doesn't have that problem, and normal RAM has it so badly that we rely on Flash to store permanent data and only use DRAM as an ephemeral cache.
Surely you could use a capacitor to buffer enough power to complete the rewrite in the event of an external power failure.
Re: Ferroelectric RAM
#10It's great stuff, but still low capacity and high cost in commercial chips. If you want to play with it, check out TI's MSP430FRxxxx microcontrollers. They have FRAM instead of Flash. Also, there are 8-pin FRAM chips with the same pinouts as generic QSPI Flash/RAM/etc chips which you can buy today. Again, it's still low-density and expensive, but that seems to be improving and it's fun to make applications which can…
And destructive reads with limited life cycles, assures a steady recurring revenue for TI...