In 1944 with work on ENIAC progressing, Eckert, Mauchly, and von Neumann proposed an improved electronic computer, the EDVAC (Electronic Discrete Variable Automatic Computer). EDVAC eventually incorporated many technological advances. For example, EDVAC needed far fewer vacuum tubes than ENIAC's roughly 18,000, because EDVAC's primary memory used more-compact and less-expensive mercury delay lines instead of vacuum tubes.