Early in the Apollo 13 movie, Lovell (Tom Hanks) is showing off the Saturn V and states that a part of what has made the moon landings possible is a belief that anything is possible, "things like a computer that can fit into a single room, and hold millions of pieces of information".

According to Wikipedia's article on core rope memory and the article on the Apollo Guidance Computer, the Block II AGC had a total storage (ROM plus RAM) of 40,960 16-bit words, or in modern terms 81,920 bytes. (We sent people to the moon with less computer code than is needed on my system to list files in a directory!)

Is there any merit to the statement that the spacecraft computer could hold "millions of pieces of information", or is it simply an attempt at setting the date for when the events took place?

  • 1
    $\begingroup$ The apollo computers (there was one on the capsule and one on the LEM) were wonders of computing for their time as much for their software as their hardware. The developers were able to cram an enormous amount of functionality in considering they has so little power and memory to work with. $\endgroup$
    – GdD
    Oct 29 '15 at 8:54
  • $\begingroup$ @GdD You're getting no argument from me there! And of course, don't discount the LVDC either. $\endgroup$
    – user
    Oct 29 '15 at 9:05
  • $\begingroup$ It's also kind of unimpressive, even by 1960s standards, to fit millions of pieces of information in a single room. A few ordinary phone books probably contain over a million listings. A million printed pages of ordinary paper can fit in a large closet. $\endgroup$ Oct 29 '15 at 16:20
  • 2
    $\begingroup$ "Millions of pieces of information" probably refers to bytes. It's an ironic assertion for those who understand what it means, because today's computers can handle many orders of magnitude more information than that. "A computer that fit into a single room" almost certainly didn't refer to the Apollo Guidance Computer, but to the larger ground computers that supported the mission. $\endgroup$ Oct 29 '15 at 18:41

"things like a computer that can fit into a single room, and hold millions of pieces of information"

was not about the Apollo computer, but about the general-purpose computers that were available around the start of the Apollo program.

In 1960, the IBM 7090 could store 32 kB. In 1964, IBM introduced the System/360, which could store up to 8 MB of data.

  • 3
    $\begingroup$ Good point. Now that you mention it, indeed there is no direct reference to that being about the onboard computers. $\endgroup$
    – user
    Oct 28 '15 at 19:39
  • 3
    $\begingroup$ Also, for that matter, the reference was to the belief and not to the computers themselves. $\endgroup$ Oct 28 '15 at 22:30
  • 4
    $\begingroup$ IBM System/360 was also used to execute the simulations for the Apollo program, so it quite directly helped accomplish the moon landings. $\endgroup$
    – jpa
    Oct 29 '15 at 11:09
  • 2
    $\begingroup$ The spirit of the statement was to describe the sense of optimism prevailing in the early '60s. Not a technically precise statement. $\endgroup$
    – Hobbes
    Oct 29 '15 at 14:19
  • 2
    $\begingroup$ @user2617804 Actually to the contrary; in early computers, making efficient use of the space (both persistent storage as well as various forms of working memory) was a prime consideration. Broadly speaking, for most computers that we think of as such (excluding for example embedded systems), this lasted into the second half of the 1990s. $\endgroup$
    – user
    Oct 29 '15 at 14:25

Not the answer you're looking for? Browse other questions tagged or ask your own question.