Simulations Show Quantum Error Not As Bad As Believed 44
aarondubrow writes "Because quantum systems become unstable quickly, their error threshold is an important factor. How many bits can 'break' before the system stops working? An international team of researchers used the supercomputers at the Texas Advanced Computing Center to simulate the error threshold of a topological quantum system and found a much higher threshold than had previously been reported."
Vacuum tube logic (Score:3, Interesting)
Really bad old days:
The latest thing was the replacement of relays with vacuum tubes. While an individual tube is reasonably reliable -- better than a light bulb -- collect a bunch together and you always have one blowing out.
I heard that with one such school sized computer after WWII the basic flip-flop was a 7 vacuum tube circuit, wired so that ANY two of the tubes could fail and the device would still function.
Several flip-flops were in a drawer. Indicator lights on the drawer front showed status. Red light on drawer, open drawer. Each flip-flop board had indicator lights showing which tubes were good.
People would race though the corridors with shopping carts of tubes doing hot replacements while the machine was running. My recollection was that even so uptime was usually measured in minutes before some other thing would break.