On Fri, 6 Jan 2017, Jeffrey Jonas via vcf-midatlantic wrote:
1) The Tyrrany Of Numbers: as computers got more complex, there were incredible problems with how to handle so many components. Thousands of tubes for ENIAC and such would not scale up. SAGE required constant maintanance, thus the dual system to keep running.
Re: SAGE Maintenance issues aside, the duplexed systems were more a military requirement for the air defense task. The follow-on to SAGE, the Hughes-built AN/FYQ-93 which went operational in 1983, was also duplexed. SAGE's maintenance procedures, including computer-controlled marginal checking, permitted a phenomenal overall uptime of 99.83%. The duplexed setup also allowed the standby system to be used for training. Mike Loewen mloewen@cpumagic.scol.pa.us Old Technology http://q7.neurotica.com/Oldtech/