3 ms·
As the Z3 cannot perform conditional branches I assume it was difficult or impossible for the hardware at the time to do anything other than move the tape in a
by longwave 8y ago
As the Z3 cannot perform conditional branches I assume it was difficult or impossible for the hardware at the time to do anything other than move the tape in a linear sequence in a single clock cycle. A stored-program computer that uses a program counter to point to the current instruction (the position on the "tape") seems to be a significant step forward.
- blattimwind 8y agoThis seems to me like a far more salient distinction than how the program is stored. Instruction pointer and explicit branching. The Z3 is still (in a theoretical sense) Turing-complete, even without branching instructions (exponential path construction).
- Squonk42 8y agoExtract from http://www.inf.fu-berlin.de/inst/ag-ki/rojas_home/documents/1997/Universal_Computer.pdf http://www.inf.fu-berlin.de/inst/ag-ki/rojas_home/documents/... "We can therefore say that, from an abstract theoretical perspective, the computing model of the Z3 is equivalent to the computing model of today's computers. From a practical perspective, and in the way the Z3 was really programmed, it was not equivalent to modern computers."
- gnufx 8y agoRight. If I recall correctly a proof it was potentially Turing complete is relatively recent and obscure, so it's difficult to consider it a general purpose computer like the SSEM. Credit to Zuse, like the pre-war Polish cryptographers, anyhow.