In 1959 the whole computer industry was on the cusp of the conversion from vacuum tubes to transistors, but it was not like jumping off the cliff. The vacuum t

In 1959 the whole computer industry was on the cusp of the conversion from vacuum tubes to transistors, but it was not like jumping off the cliff. The vacuum tube predecessor to the 7090 was the 709. Vacuum tubes were unreliable because they burned out frequently. The transistor machines were a huge step forward in reliability and the 7090 was at least 20 times faster. Once the transistor machines came out the vacuum tube ones were dead. I imagine BofA was faced with the decision of a year's delay to get the new systems and rewrite the software or go ahead with what they had. Those were the days where every new machine required a rewrite of all your software. OTOH there wasn't very much of it. ERMA had only 4000 bytes of memory and the 7090 had 32K 36 bit words. Processors for satellites are entirely different animals. They have to be radiation hardened. It's not a matter of waiting for generation x of the x86 to prove itself. Commercial processors flat out wont work in high radiation environments.