J. Andrew, On 1/1/09, J. Andrew Rogers <[email protected]> wrote: > > > On Jan 1, 2009, at 2:35 PM, J. Andrew Rogers wrote: > >> Since "digital" and "analog" are the same thing computationally ("digital" >> is a subset of "analog"), and non-digital computers have been generally >> superior for several decades, this is not relevant. >> > > > Gah, that should be *digital* computers have generally been superior for > several decades (the last non-digital hold-outs I am aware of were designed > in the late 1970s).
Ignoring the issues or representation and display, I agree. However, consider three interesting cases... 1. I only survived my college differential equations course with the help of a (now antique) EAI analog computer. Therein, I could simply wire it up as the equation stated, with about as many wires as symbols in the equations, without (much) concern for the internal workings of either the computer or the equation, and get out a parametric plot any way I wanted. However, with a digital computer, maybe there is suitable software by now, but I would have to worry about how the computer did things, e.g. how fine the time slices are, etc. Further, I couldn't just "throw the equation at the machine" with a digital computer much as I could do with the analog computer, though again, maybe software has caught up by now. 2. Related to above and mentioned earlier, electrolytic fish-tank analogs have long been used to characterize electric and magnetic fields. While these may not be as accurate as digital simulation, they are in TRUE walk-around 3-D representation, and changes can be made in seconds with no need to verify that the change indeed reflects the intended change. This is another example where, at the loss of a few "down in the noise" digits, you can be SURE that the model indeed simulates reality. The same was long true of wind tunnels, until things got SO valuable (and competitive) that it was worth the millions of dollars to go after those last few digits. 3. Conditioning high-speed phenomena. Transistors are now SO fast and have SO much gain that they have become nearly perfect mathematical components. Most people don't think of their TV tuners as being analog computers, but... Steve Richfield ------------------------------------------- agi Archives: https://www.listbox.com/member/archive/303/=now RSS Feed: https://www.listbox.com/member/archive/rss/303/ Modify Your Subscription: https://www.listbox.com/member/?member_id=8660244&id_secret=123753653-47f84b Powered by Listbox: http://www.listbox.com
