13 Feb
2015
13 Feb
'15
5:25 p.m.
Ben,
I'm planning on 8-bit paper tape for I/O, but I was in touch with a gentleman from
Brazil a few months ago that designed his architecture around 5-bit words. This allowed
him to use the Baudot code and make use of teletype equipment that can still be found
without too much difficulty. 8-bit ASR-33s are worth their weight in gold these days, but
the 5-bit model 32 (or a 28 and tape peripherals) is much more reasonable. -C
On Feb 13, 2015, at 7:14 PM, ben wrote:
On 2/13/2015 6:02 PM, Cory Heisterkamp wrote:
Tom, any reason for choosing the Harvard
architecture?
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 enough. 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
The alu has never relay been a problem with relays, but what about main
storage? Punched tape (paper/film/card) is no longer with us for I/O.
Ben.