1. Starting in the 1920s, Vannevar Bush and others developed mechanical differential analyzers . 2. One of the inspirations for ENIAC was the mechanical analog Bush differential analyzer . 3. The "'Rockefeller Differential Analyzer "'was an advanced version of the Differential Analyzer invented in 1931. 4. The "'Rockefeller Differential Analyzer "'was an advanced version of the Differential Analyzer invented in 1931. 5. The UCLA differential analyzer from the same era is also shown briefly for the same reason. 6. :It functions as a differential analyzer of the attributes " surprise " and " panic ". 7. This model came as a result of his work on Vannevar Bush's differential analyzer , an early analog computer. 8. In a differential analyzer , the output of one integrator drove the input of the next integrator, or a graphing output. 9. The primary advantages of a DDA over the conventional analog differential analyzer are greater lash " issues of mechanical analog systems. 10. Additionally a small version of the differential analyzer was completed by September 1948, although it appears to have seen little use.