> she made groups of operations and in the text of her note specified when they should repeat.
Does anyone know what "should repeat" means? Was the machine capable of repeating or does this mean the human operator needed to do the repeating?
Does anyone know what "should repeat" means? Was the machine capable of repeating or does this mean the human operator needed to do the repeating?
If you're interested in that kind of thing I wrote a description of the entire instruction set a while back: http://h14s.p5r.org/2012/11/punched-cards.html.
Thanks for the in-depth, and wonderfully clear write-up.
The London Science Museum built a fully working Difference Engine, to Victorian tolerances so it could have actually worked.
I heard of a project to build a modern working replica but I don't know if anything ever came of it.
It's really just a series of mathematical steps with a store of values in between. Notions that would have clearly taken it from being a series of mathematical steps, to a program, such as branching, looping, or jumping are left completely unspecified. So her 'loop' was specified literally as "here follows a repetition of operations 13-23".
In other words, "should repeat" is left an as exercise to the reader.