ENIAC was physically enormous, filling roughly a large room: about 100 feet (30 meters) long, 10 feet (3 meters) high, and 3 feet (1 meter) deep, occupying on the order of a few hundred to around 1,800 square feet of floor space and weighing over 27–30 tons. It consisted of long rows of equipment racks packed with nearly 18,000–20,000 vacuum tubes, thousands of other components, and substantial power and cooling hardware.
Physical size
- Dimensions are commonly described as roughly 100 feet long, about 10 feet high, and a few feet deep, arranged in a U-shaped layout of panels along a room.
- Depending on the source and configuration, ENIAC is said to occupy about 300 to 1,800 square feet of space and to weigh on the order of 27,000–30,000 kilograms (about 27–30 short tons).
Memory and storage
ENIAC did not have memory in the modern RAM sense; instead it used 20 “accumulators,” each holding a 10‑digit decimal number using electronic ring counters built from vacuum tubes. That means the main high‑speed storage capacity was about 200 decimal digits total, which is well under 100 bytes if converted into modern binary terms.
In addition, ENIAC relied on plugboards, switches, and function tables for storing constants and controlling programs, and it had no internal disk or similar mass storage; input and output were handled via punched cards.
