View source for 1.2.3 Early Electronic Computers (ENIAC, UNIVAC)

== Chapter 3: Giant Brains in Rooms: Early Electronic Computers ==
This chapter dives into the era of the first true electronic computers—machines so large they filled entire rooms, yet they changed the world forever. The development of these machines was often driven by urgent, high-stakes needs, demonstrating how external pressures can accelerate technological innovation.

=== ENIAC: The Super-Sized War Calculator ===
The ENIAC (Electronic Numerical Integrator and Computer) was born out of urgency during World War II. The U.S. Army needed to quickly calculate "firing tables" for artillery—complex mathematical calculations to figure out where shells would land. Doing this by hand was slow and prone to errors. So, in 1941, work began on a machine to automate these calculations. This military imperative provided immense resources and a clear, high-stakes goal, accelerating its creation and pushing boundaries beyond what might occur in peacetime.   

ENIAC was enormous, often filling entire rooms. It was composed of many individual panels, and its "brain" was thousands of glowing vacuum tubes. These tubes acted like super-fast switches, turning electrical signals on and off. ENIAC was incredibly fast for its time, performing calculations in hours or minutes that would have taken weeks or months by hand. It could perform 5,000 simple addition or subtraction operations per second.   

However, this new electronic technology brought its own set of problems. To change what ENIAC did, engineers had to manually rewire it using cables and switches. This was a huge job that could take weeks, unlike typing code on a keyboard today. All those vacuum tubes made it massive, consumed a huge amount of electricity, and generated a lot of heat, meaning it needed an elaborate cooling system. Additionally, vacuum tubes were not very reliable and failed frequently, so ENIAC required constant maintenance. This illustrates that technological progress often involves trading one set of limitations for another, and that the initial phase of a new paradigm is often clunky and unreliable before refinement.   

Despite its challenges, ENIAC proved that electronic computers were possible and incredibly powerful. Its success inspired new ideas, particularly the concept of storing instructions inside the computer's memory. This "stored program" idea was a profound conceptual leap, enabling true flexibility and general-purpose computing by allowing a single computer to run many different applications without being physically rebuilt for each one. It also sparked the development of easier ways to program, leading to early programming languages like FORTRAN and COBOL.   

=== UNIVAC: The First Computer for Business and Beyond ===
The UNIVAC (UNIVersal Automatic Computer) was another groundbreaking electronic computer, developed by John Mauchly and Presper Eckert, two of the same people who worked on ENIAC. The UNIVAC was special because it was one of the first general-purpose computers and, importantly, the first commercially successful computer. This meant it was built to be sold to businesses and organizations, not just for scientific or military use. This marked a crucial shift in the computer's role from a specialized tool to a general-purpose machine for data processing in everyday industries.   

The first UNIVAC I was delivered to the U.S. Census Bureau in 1951 to help process the huge amounts of data from the 1950 census. It became widely famous in 1952 when it accurately predicted the outcome of the presidential election, showing the public just how powerful these machines could be.   

Like ENIAC, early UNIVACs used vacuum tubes, but they also pioneered the use of magnetic tape for storing and inputting information. This was a significant development. Magnetic tape allowed the UNIVAC to handle huge amounts of data, such as over a million numbers on one reel, and to read and write information incredibly fast—at a rate of ten thousand decimal digits per second. This highlights a new focus beyond just raw computation; machines needed to efficiently manage and process vast amounts of data, laying the groundwork for database systems and information management central to today's digital world.   

UNIVAC was designed to handle large amounts of both numbers and words, and to do it automatically with very little human help. This made it perfect for tasks like managing insurance records, doing payroll, or analyzing market research. It demonstrated to businesses how technology could make them more efficient and productive. UNIVAC also featured important early software, including FLOW-MATIC, which influenced the development of the COBOL programming language. This was another step towards making computers easier to program, showing that the evolution of software was just as vital as hardware advancements in unlocking the computer's full potential. While UNIVAC was a leader in the early 1950s, it eventually lost its top spot to other companies like IBM. However, its innovations, especially in magnetic tape and commercial applications, paved the way for the computer industry as it is known today.