Definition:
ENIAC was the first general-purpose, fully electronic digital computer, completed in 1945 at the University of Pennsylvania. It was built to calculate artillery firing tables for the U.S. Army during World War II. Unlike mechanical computers, ENIAC used vacuum tubes instead of gears and could perform calculations at electronic speeds.
Key Facts:
- Built: 1943-1945
- Purpose: Calculate ballistic trajectories
- Size: Occupied 1,800 square feet (167 m²)
- Weight: 30 tons (27,000 kg)
- Power: 150 kilowatts (enough for 150 homes)
- Components: 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays
- Speed: 5,000 operations per second (revolutionary for the time!)
Simple Analogy
ENIAC vs Modern Computer:
🏢 ENIAC (1945):
├─ Size: Entire room (1,800 sq ft)
├─ Weight: 30 tons (like 6 elephants)
├─ Power: 150 kW (your whole neighborhood)
├─ Speed: 5,000 operations/sec
├─ Memory: 20 numbers
├─ Programming: Rewire by hand (took days)
└─ Cost: $487,000 (1945) = $8 million today
📱 Your Smartphone (2024):
├─ Size: Fits in pocket
├─ Weight: 200 grams (less than 0.5 lbs)
├─ Power: 5 watts (like a night light)
├─ Speed: 1 trillion operations/sec (200 million times faster!)
├─ Memory: Billions of numbers
├─ Programming: Download apps instantly
└─ Cost: $1,000Your phone is 200,000,000× faster and fits in your pocket!
Example:
Calculating a Trajectory The Problem Artillery Question: “If I fire a shell at 45° angle with velocity 500 m/s, where does it land?”
Manual Calculation (1943)
Human "Computer" Process:
Hour 1-2: Set up equations
├─ Write out ballistic formulas
├─ Account for air resistance
├─ Factor in wind
└─ Include Earth's rotation
Hour 3-10: Numerical integration
├─ Divide trajectory into 100 time steps
├─ Calculate position at each step
├─ Use mechanical calculator for each multiplication
│ (Each multiplication: 30 seconds)
│ (Each division: 1 minute)
└─ 100 steps × 20 operations each = 2,000 calculations
Hour 11-20: Check work
├─ Verify calculations
├─ Re-do any errors
└─ Plot results on graph
Hour 21-30: Create firing table entry
├─ Format results
├─ Add to master table
└─ Document assumptions
Total Time: 30-40 hours
Error Rate: 2-5% (human mistakes)
ENIAC Calculation (1946)
ENIAC Process:
Week 1: Program ENIAC (one-time setup)
├─ Design calculation flow
├─ Wire panels for ballistic equations
├─ Connect function tables
└─ Test configuration
Day 1 (after setup): Run calculations
├─ Input: velocity, angle, environmental factors
├─ ENIAC divides trajectory into 100 steps
├─ Calculates position at each step
│ (Each calculation: 0.0002 seconds)
│ (100 steps × 20 operations = 0.4 seconds)
├─ Output: Complete trajectory
└─ Punch results to cards
Total Time: 30 SECONDS per trajectory
Error Rate: 0% (if programmed correctly)
Speed Improvement: 3,600× FASTER than humans