First off, I highly recommend the movie. Great story, fine acting - Big Bang's Sheldon as you've never seen him before - and a fascinating dollop of computer history.
The 7090 was one of IBM's first transistor-based computers, and was intended for just the scientific computing that NASA needed for the Mercury and Gemini space missions. Before that NASA relied on human computers, teams of people armed with mechanical calculators, that performed the calculations needed to figure out where, for example, a space capsule would land so the US Navy would be close enough to pick it up before it sank.
That was okay for the early missions, which were suborbital-cannon shots really - up and down trips like those planned for the first commercial space flights by Virgin and others. But life is a lot more complicated when you're traveling at 17,000 MPH and need to hit a 20 mile square target. Thus NASA became an early adopter of IBM's latest technology.
Enter the computer
Problem #1: no one knew how to make the new computer work. There were only a few thousand electronic computers on the planet in 1961, and they weren't user friendly. Fortran and Cobol were the most popular high-level languages. Basic was yet to be invented.
The 7090 was six times faster than its tube-based predecessor, the 709. It ran on 50,000 discrete transistors - integrated circuits had only just been invented - and there probably isn't a computer today of any sort with so few transistors. It ran on a 36 bit word and used 6 bit characters.
Even getting the beast into the computer room was a problem: it was bigger than the doorway. And IBM's legendary sales force was focused on business applications, not space travel.
That's when one of the heroines of the story, Dorothy Vaughn, who'd been supervising the human computers, stepped up, taught herself Fortran, and got the system working. She also got her team new jobs, working on the 7090.
The economic imperative
Much is made, in the movie, of the incredible speed of the 7090: 24,000 calculations per second! While there probably isn't a $2 microcontroller that is that slow today, compared to a room full of people with adding machines, it was stupendous - which made it worth the almost $500,000 (today's money) monthly rental that IBM charged.
The Storage Bits take
Hidden Figures is highly recommended for techies of all levels. As the pace of technological change has accelerated, we can all relate to people struggling to learn and adapt as they apply new tools to new problems.
Computers are part of the fabric of modern culture now, with over 1 billion smartphones sold. But it wasn't that long ago that they were alien beings, kept in pristine glass houses, and attended by a priesthood of IT workers versed in the arcane voodoo of EBCDIC, JCL, 1600 bpi tape, line printers, and card readers.
Hidden Figures humanizes this lost world with an appealing true story and a great sub-plot from the early days of computers. Even your non-techie significant other will like it!
Courteous comments welcome, of course.