5 ms·
Most superconducting logic families aren't using transistors at all. They use Josephson junctions, which are just two pieces of superconductor separated by a n
by floxy 3y ago
Most superconducting logic families aren't using transistors at all. They use Josephson junctions, which are just two pieces of superconductor separated by a non-supercondutor. RSFQ (Rapid Single Flux Quantum) uses millivolt-high picosecond-long pulses to represent logic 1 and their absence as logic zero, instead of using voltage level as in CMOS.
https://ieeexplore.ieee.org/document/783712 https://ieeexplore.ieee.org/document/783712 (770 GHz toggle flip-flop in 1999)
https://www.physics.sunysb.edu/Physics/RSFQ/Projects/WhatIs/rsfqre2m.html https://www.physics.sunysb.edu/Physics/RSFQ/Projects/WhatIs/...
- Culonavirus 3y agoSooo, a 770 GHz processor? Do I understand it correctly? Jesus.
- yetihehe 3y agoIf using that flip-flop, whole processor will be closer to 100ghz (typically there are multiple transistors which need to stabilise before you have a result of computation). But probably those superconductors could enable even faster transistors and maybe we could get 1THz processors.
- aitchnyu 3y agoLike IDE ribbon cables gave way to sleek SATA cables, we could have another parallel to serial transition from silicon multicore crap to superconducting single core.
- jacquesm 3y agoNo, you'll get superconducting multicore because all that will happen is that the bloat will expand to consume the new cycle budget. This has already happened many times.
- dtx1 3y agoI'm looking forward to Chromium version 4201337 needing 20% of my 1Thz CPU to render simple text.
- regularfry 3y agoWe'll get superconducting multicore because as a first step everyone will just map what they already know to the new space. Which is fun.
- MayeulC 3y agoI suspect you'd still need very low temperatures to make this work, even with a high temperature superconductor: low temperatures reduce thermal noise, which may be an issue at such time scales (unless you pump a lot of energy per bit, which means high voltages (limits scaling) or current/capacitances (also limits scaling).
- jakeinspace 3y agoAre you aware of any obvious issues with manufacturing Josephson junctions using photolithography? Like, would switching to an LK-99 or similar set us back to the 70s in terms of wafer density/size?
- floxy 3y agoYou might be interested is this video, which talks about the EDA issues for RSFQ logic: https://www.youtube.com/watch?v=3O6GpFCIxv0 https://www.youtube.com/watch?v=3O6GpFCIxv0 ...and... https://en.wikipedia.org/wiki/Josephson_junction_count https://en.wikipedia.org/wiki/Josephson_junction_count