'Universal' Memory Aims To Replace Flash/DRAM 125
siliconbits writes "A single 'universal' memory technology that combines the speed of DRAM with the non-volatility and density of flash memory was recently invented at North Carolina State University, according to researchers. The new memory technology, which uses a double floating-gate field-effect-transistor, should enable computers to power down memories not currently being accessed, drastically cutting the energy consumed by computers of all types, from mobile and desktop computers to server farms and data centers, the researchers say."
But I like volatility! (Score:5, Interesting)
Early DRAM (Score:5, Interesting)
Interesting (Score:4, Interesting)
"We believe our new memory device will enable power-proportional computing, by allowing memory to be turned off during periods of low use without affecting performance," said Franzon.
Huh! A new chapter opens in the "program/OS optimization" - heap fragmentation will have an impact on the power your computer consumes, even when not swapping (assuming the high density and non-volatility will render HDD obsolete... a "no more swapping, everything is non-volatile-RAM, with constant addressing cost" becomes plausible).
Re:10 Years away (Score:5, Interesting)
Re:But I like volatility! (Score:5, Interesting)
Re:But I like volatility! (Score:4, Interesting)
Re:Early DRAM (Score:5, Interesting)
You are correct. Currently, DRAM stores information as a N-channel MOSFET attached to a capacitor. This MOSFET is leaky. There's no getting around this leakage. This leakage acts to discharge the capacitor where the bit is stored.
You can try to decrease this leakage in a number of ways. You can increase the threshold voltage of the gate, but that means you'd have to increase the voltage the DRAM operates at as well, or else you wouldn't be able to charge the capacitor. This means you'd increase the energy-per-operation of the DRAM cell, because you'd have to charge the capacitor up more. You'd burn up more power, because the leakage is proportional to the operating voltage, but the charging energy is proportional to the square of the voltage.
Alternatively, you could increase the capacitance. But this means that the capacitor would take longer to charge, slowing down every operation. Also, doubling the capacitor size means doubling the energy it stores (and therefore burns with every operation). It also makes the DRAM cells bigger, meaning you can't fit as many on a silicon wafer.
Neither of these is what you want to do. In fact, you want to do the opposite for traditional DRAMs. It's counterintuitive, but you get more density, more speed, and less power by increasing the refresh rate (or rather, increasing the refresh rate is a side-effect of all of those). Unfortunately, lithography limits and quantum mechanics mean we're having a hard time going any smaller.
It's truly amazing what we can do. The oxide layer (essentially a layer of quartz glass between metal and silicon) on a MOS these days is 5 atoms thick. We're going to have to come up with something that relies on something other than the traditional semiconductor effects if we want to continue forward.