On Fri, May 11, 2018 at 6:21 PM, Dave Horsfall <dave@horsfall.org> wrote:

Way back on this day in 1941, Conrad Zuse unveiled the Z3; it was the first programmable automatic computer as we know it (Colossus 1 was not general-purpose). The last news I heard about the Z3 was that she was destroyed in an air-raid...

This pretty much started computing, as we know it.

Again be careful -- we don't want to go down that rat hole. There has been always been an argument since it (as well as Atanasoff and Aiken's machines all) lacks a conditional branch. Although, I do believe some one the UK proved the Z3 to be Turing complete; but the argument will always be there.

What I tell people is that Babbage theorized the computational device and Lady Ada extended the theorized to general programmability (to play music I believe) but it was never built and she and Babbage argued a bit about it. The Loom folks demonstrated that the idea programmability was possible. Zuse put the two idea together and reduce it practice.

But .. until we also include a conditional branch the ability to do self modify code we don't really have the machine with think of as the automatic programmable computer.

Check out: http://page.mi.fu-berlin.de/rojas/1993/Who_invented_the_computer.pdf its a fun read.

There is a nice table in it:

Machine Memory & CPU Separated Conditional Branching Soft or Hard Programming Support Self Modify Indirect Addressing

Babbage yes yes soft proposed no

Zuse yes no soft no no

Atanasoff yes no hard no no

Aiken Mark1 no no soft no no

ENIAC no partial hard no no

Manchester yes yes soft yes no