I found this link to a slide show called A Complete history of Mainframe Computing by R. Arzoomanian. The pictures are fantastic. I thought this tidbit was very remarkable: “In fact, by the time it was retired in 1955, it was estimated that the ENIAC by itself did more calculations than all of humankind did up to 1945.”
However I have to take issue with some of what the author says and claims. First off, I use as my reference a book called “Bit By Bit An Illustrated History of Computers” by S. Augarten. Some things Mr. Arzoomanian says are actually errors, such as when he claimed that the ENIAC cabinets were 49 feet high. Perhaps he meant 49 feet long.
The author calls them the “two heroes”, but gives their names as Mauchly and Presper, which is his first name, not his last name, which is Eckert.
But I take exception to the claim that he makes over and over that the vacuum tube computers were unreliable. Yes, they used a lot of heat producing tubes. But the engineers early on learned that if the plate voltage was reduced, the lower power meant a greatly increased lifetime. Also, the operators ran tests on the computers during maintenance time, and if they found a problem with marginal tubes, they fixed it, so during regular operation there were very few problems with the computer. Referring to tubes, the author said,
“However, they used a lot of power, got very hot, and were very unreliable. These were tradeoffs he and others had to live with and were unfortunate characteristics of the computers built from them.”
He uses the word very twice and the word unfortunate, and I have to take him to task for that. He failed completely to say the one positive thing about tubes (valves), and that was they were not subject to the physical limitations of mechanical devices and could operate at speeds far exceeding mechanical relays, and so ushered in the advent of the modern electronic computer. Without tubes we would not have had the opportunity to develop the hardware and most importantly the software that modern computers use.
In the comments, someone brought up the computers that Konrad Zuse made in Germany during the war. The early generations of Zuse’s computers were electromechanical, they used relays, not tubes. The relays were much slower and somewhat prone to errors if they were operated too quickly. Zuse used 35 mm film for the punched tape.
In the last decade, the British declassified information about Colossus, the computer they used for deciphering the German encrypted radio messages. This was kept a secret for over fifty years, and only recently have they claimed that the Colossus was the first electronic computer. Mr. Arzoomanian had the audacity to call his document “The complete history..” but he totally forgot to even mention this and several other mainframe computers. We ran a Honeywell Bull mainframe for decades, and used it with PC or IBM Plug Compatible (Bus and Tag) peripherals. He also didn’t mention that his “heroes”, Eckert and Mauchly, lost in court to Atanasoff’s ABC computer when it was determined in court that Atanasoff had built the first computer, not Eckert and Mauchly.
I have to thank the author for showing all those old pictures of mainframes, because most people have never seen this important part of computer history. But I highly recommend that the reader take this document with a large number of grains of salt, and refer to a more accurate document such as that which I referred to at the beginning. A good place to start would be Wikipedia. After reading the remaining photo descriptions, I then saw that the author was working in the IBM mainframe environment and it’s obvious that he would be biased towards that brand of mainframe.