ENIAC ....

On 2011 Jan 24, at 1:09 PM, Tony Duell wrote: I'm not fully acquainted with the Antikythera device but, it was composed of >30 gears, with some sort of differential mechanism in there. It solves a couple of equations in parallel. I'm not completely clear on how complex those equations are, i.e. whether they are more than a single simple relationship each, but it wasn't a simple device, it was more than a rotary slide rule. For the sake of discussion, here are some incremental definitions of 'computer' (not to say that these are the only possible definitions): 1 - something that performs a computation/calculation 2 - something that executes a program automatically (solves an equation where the equation is more than one simple arithmetic operation) 3 - something that is programmable (can solve a wide variety of equations) 4 - a stored-program (/universal) machine By some standards, something that fits *only* in category 1 is a calculator, e.g. a slide rule is an analog calculator, an adding machine is a digital calculator. Parallellism adds another level of complexity in the characterisations. And if one has some appreciation for the history of mathematics and logic, one know it becomes another argument as to what constitutes a computation or calculation. The following categorisations could be made: 1: EDVAC, ENIAC, Harvard Mark 1, ABC, Antikythera, adding machine, slide rule 2: EDVAC, ENIAC, Harvard Mark 1, ABC, Antikythera 3: EDVAC, ENIAC, Harvard Mark 1 4: EDVAC It may be one could argue the Antikythera is in a grey area between 1 and 2. Depending on your definition, one can call the Antikythera Device a fixed-program analog computer. - One can pick or choose a definition and declare their device a computer to suit one's purposes if one is so inclined. Things become a little more controversial when one declares somebody else's device not a computer, unless you're being completely clear about what definition you're working with.