Apollo Guidance Computer

Brent Hilpert hilpert at cs.ubc.ca
Sun Sep 21 14:56:00 CDT 2008

Dan wrote:
> Yes, but I think part of this hobby is also having some level of
> authenticity.
> Although many of the original parts can't be available, some level of
> hardware consistency is maintained.
> Another group redesigned the ENIAC into a FPGA chip.
> Part of an engineer's job is to design within constraints, you lose that
> when using advanced technology.
> Eliminating this factor when trying to replicate a system is making it
> too easy.
> Besides what fun is for all to stand around the table and look down on
> one lonely FPGA chip ?

Chuck Guzis wrote:
> On 21 Sep 2008 at 10:42, bfranchuk at jetnet.ab.ca wrote:
> > But that is what made it special - the components at the time.
> > They have 3 input NOR's in tiny logic, so do smaller PCB's
> > if you want a smaller system. :)
> One could also make use of transistor arrays to recreate the original
> RTL part.  Given that there were some 5000 of these packages in the
> original (IIRC), that might make for a project a bit too large to
> chew.  Given that integration is used to decrease this package count
> by 9/10ths, what's the problem with substituting some programmable
> logic?  How is that "less authentic" than substituting MSI TTL for
> SSI RTL?  One could use the extra space in the rack to store a six-
> pack of one's favorite beverage. :)

I'd say it's just a matter of preference of where one wants to draw the line.
Just for the sake of discussion, I'd suggest using SMD CMOS 4025 triple 3-input
NOR gates, or 7410 triple 3-input NAND gates with negative logic, to fairly
closely mimic the original implementation. (Might depend on whether wire-AND
connections were used much in the original.)

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