The first computers were UNIVAC and ENIAC, which were vacuum chambers as big as a room. The first official computer was the ENIAC (Introduced in 15 February 1946), which was the first programmable, electronic, general-purpose digital computer. UNIVAC (introduced in June 14 1951), on the other hand, was the first general-purpose electronic digital computer for business applications in the USA. Both machines used vacuum tubes and could perform about 1,000 calculations per second. However, while producing tremendous calculations per second they were inefficient in terms of input energy as they were power-hungry. Further the input for data was in the form of punch cards and the instructions which were given to the computer were in the form of bundles of punch cards that had to be inserted into the device making it much slower than the 2nd generation computers we are familiar with. However, today we instead of vacuums we see transistors; microscopic devices that can store a single on or off state. Over the years this technology has gotten smaller, and thus faster with modern consumer transistors only being 7nm in size, allowing several billion to be placed in a computer (APPROX. 15.3 billion in the Xbox Series X).