The edvac came after the eniac (its predecessor). The main difference was that with the eniac if you wanted to complete a certain process different vacuum tubes had to be tampered with, whereas with the edvac john von neumann and others realised that computers could be programmed which meant you didnt have to tamper with the hardware each time you wanted to complete a different a task. read more
ENIAC (Electronic Numerical Integrator And Computer) was the first general purpose computer. It was invented by J. Presper Eckert and John Mauchly. It was primarily designed, and used, to calculate artillery tables for the Army, it was also used to study the feasibility of thermonuclear bombs. read more
EDVAC (Electronic Discrete Variable Automatic Computer) was the successor to ENIAC, was binary based, and used stored programs, and was also designed by Eckert and Mauchly, UNIVAC I (UNIVersal Automatic Computer I) was the first commercial computer. It was designed by the same two men who designed ENIAC and EDVAC. read more