On Jan 25, 2015, at 6:06 PM, Barney Wolff <bar...@databus.com> wrote:
> On Sun, Jan 25, 2015 at 02:24:52PM -0800, Stephen Satchell wrote: >> >> Today's computers don't use clocks derived from 50- or 60-hertz >> power-line frequency. The last computer I remember seeing with such a >> clock was the IBM System/360. The System/370 used a motor-generator set >> for the power supply, so it had to get its real-time clock time source >> another way. > > The 360/95 and /91 also used 400 Hz from a motor/gen. Water cooled, too. > One of my fondest war stories is when the power was turned off for July 4th > weekend but the water was left on. That made the transformers smaller/cooler and more efficient. I seem to remember a 195 as well but maybe it is just CRS.