On Mon, Nov 28, 2016 at 10:05 PM, Tony Duell <[email protected]> wrote:
> My guess is that EPROMs of that time were not fast enough for the 8X305 to > run > flat out. Bipolar PROMs were too expensive in the capacity needed. So > they copied the code into (fast enough) SRAM at startup. > AFAIK, at the time the IRMA II was made, 2K*8 fast(ish) bipolar PROMs were not much different in price from the 2K*8 static RAMs they used. I think the purpose most likely was to allow choice of different firmware at runtime, either for different feature sets, or for diagnostics.
