Continuous-system simulation and analog computers: from op-amp design to aerospace applications

Analog computer simulation has been completely replaced by more accurate, cheaper, and convenient digital techniques. Analog computers provided three decades of real simulation experience well before digital computers were fast enough and have left a significant legacy of mathematical modeling techniques. Almost none of the machines produced in the course of the 30-year rise and fall of a small industry are left. We were in a well-motivated hurry to develop computers and guided weapons and to get into space first. We lacked the time, funds, and floor space to preserve aging artifacts. ASTRAC II and LOCUST joined more important analog simulator landmarks on the trash heap: MIT's great differential analyzer, Grumman Aircraft's impressive lunar-lander mockup, and NASA/Huntsville's lunar-excursion simulator are all gone for good. The same fate overtook almost all historically significant digital computers. Each machine would have needed over 2000 square feet of museum space. Museums find that much space only for dinosaur skeletons.