cdshaw@watrose.UUCP (Chris Shaw) (03/17/85)
................................ > > > Of course, the ballistic gate speeds (100 femtosecond range) ... > > > > about 10 picoseconds delay per gate ... > > Nope. Try Josephson junctions. Gate delays less than 10ps ... "About 10ps" is compatible with that and both are far from 100fs. IBM was working on Josephson junctions when I was a youngster. What is the holdup? ................................... According to Feb 25, 1985 ElectronicsWeek, research continues on Josephson technology. The "holdup" is that IBM gave up its rather large research effort about 18 months ago. The goal of the research was to have a mainframe computer by late 1986. The problem was (among other things) getting the circuits cold enough to superconduct, and/or finding materials that don't require temperatures as low as 4 Kelvins. The Japanese still hope to have something not too far off. Their efforts are proving fruitful... NTT (Japan's AT&T) has reported "..a 1-K lead-based Josephson memory chip that exhibits a 3.3nS access time, with gate delays of 4.2 pS..." IBM is still working on other high-speed projects, however... read the article for full details. Chris Shaw