John Vincent Atanasoff was American designer who developed the first electronic computer in 1939, he incorporated innovations in computing including the use of binary arithmetic, regenerative memory, parallel processing, and separation of memory and computing functions. At Iowa State, Atanasoff researched the use of slaved Monroe calculators and IBM tabulators for scientific problems. In 1936 he invented an analog calculator for analyzing surface geometry. The fine mechanical tolerance required for good accuracy pushed him to consider digital solutions.The key ideas employed in the ABC included binary math and Boolean logic to solve up to 29 simultaneous linear equations. The ABC had no central processing unit (CPU), but was designed as an electronic device using vacuum tubes for digital computation. It also used separate regenerative capacitor memory, a process still used today in DRAM memory.