[TUHS] The birth of the Z3

[Clem Cole]

On Fri, May 11, 2018 at 6:21 PM, Dave Horsfall <dave at 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
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