The Brainiac that was ENIAC

What Was ENIAC and What Did It Do?

…and who is your daddy and what does he do?

ENIAC was the world’s first large scale digital-electronic general purpose computer. It was designed specifically to be reprogrammable, so that it could handle a variety of numerical problems.

ENIAC was laid out in a modular design, consisting of multiple panels/function tables. Each panel was in charge of different functions.

  • Initiating Unit: Controlled the startup and shutdown operations.
  • Cycling Unit: Sent signals to modules to begin transmitting data and maintained synchronization between all modules.
  • Accumulator Unit: Could perform up to 5,000 addition and subtraction operations between other accumulators.
  • Division/Square Root Unit: Some of these accumulators could be routed to an additional supplementary unit to perform division and square root calculations.
  • High-Speed Multiplier Unit: Another bank of accumulators to handle multiplication operations.
  • Programmable ROM Unit: Utilized vacuum tubes and ten-position ring counters to store data. Essentially being an electronic emulation of a mechanical adding machine.
  • Master Programmer: Handled looping sequences.
  • Reader/Constant Transmitter: An IBM card punch machine in which the operators could interface with the machine. It acted as the input.
IBM Card Puncher
  • Printer: Another IBM card punch machine, but instead printed out the results of a given task.

The Nuts and Bolts of ENIAC

Well, technically the vacuum tubes and resistors.

The specification list for the device was quite expansive. By the end of its operation, ENIAC consisted of:

  • 17,468 vacuum tubes
  • 7,200 crystal diodes
  • 1,500 relays
  • 70,000 resistors
  • 10,000 capacitors
  • Approximately 500,000 soldered joints
Vacuum tubes needed constant replacement due to failures.

The History and Legacy of ENIAC

ENIAC began as a secret World War II military project in 1945, under the codename Project PX. The Army was looking for a way to speed up the calculation time of artillery tables. Work was carried out at the University of Pennsylvania’s Moore School of Electrical Engineering. With the design being carried out by John Mauchly and J. Presper Eckert.

John Mauchly(left) and J. Presper Eckert(right).

The project would not be completed until after the war was finished. The final cost was $500,000 or 6.1 million dollars adjusted for inflation. The completed machine was announced to the public in 1946. Because of its versatility, the ENIAC was sought after by various academic institutions, other branches of the military, and even saw work on developing the Hydrogen bomb. This kept it busy for many years until it was officially turned off on October 2, 1955.

The ENIAC demonstrated what could be accomplished with computational devices. It’s design would pave the way for other, more advanced computers. It kicked off the informational age and the path to personal computers we utilize today.