building my own relay computer

Tom Sparks tom_a_sparks at
Fri Feb 13 22:02:08 CST 2015

On 14/02/15 11:02, Cory Heisterkamp wrote:
> Tom, any reason for choosing the Harvard architecture?
it may have some Modified Harvard architecture
the computer is NOT Stored-program based, it may have a small (128/256
byte) CPU styled cache

> I'm currently in the middle of a relay computer build so I'll toss in
my 2 cents.
> The most important thing I hit on early is to define the instruction set,
> work out a number of potential applications/uses on paper (or excel),
> and step through each instruction to make sure the machine is capable
> You'll probably discover a number of efficiency improvements you can
make to the hardware while doing so,
> and a few "hardware subroutines" worth adding.
> You can also baseline how long a program will take to run if you
settle on a clock rate, and determine if there's a better way to do it. 
> Ultimately, relay computers are SLOW. Don't take 6 cycles to do what
could be accomplished with a couple extra relays and a single pulse.
> Well thought out HW and instructions will pay big dividends when the
soldering iron comes out. -Cory
good point, I am prototyping the computer design in software and
software in 6502 assembly

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