> From:         David Brodbeck <g...@gull.us> 
> Date:         Wed, 20 Oct 2010 14:58:40 -0700 
> Message-id:   <aanlkti=zo1ojzcqs4xyezvmkonmt6uv_vmqki0hik...@mail.gmail.com> 

David Brodbeck wrote:
> On Wed, Oct 20, 2010 at 1:10 PM, Arthur Chance <free...@qeng-ho.org> wrote:
> > On 10/20/10 20:46, Bob Hall wrote:
> > Getting back to reality, although I never did it (fortunately), a friend of
> > mine who was about a decade older than me (I'm mid/late 50s) had the
> > experience of programming microcode on a machine by inserting brass slugs
> > for 0s and ferrite slugs for 1s on a pin board. Anyone got any idea what
> > that was? He was (UK) military so maybe it wasn't a generally known box.
> Don't know about that one, but some early desktop calculators (and I
> think some early computerized phone switching systems) used etched PC
> boards as ROM.  The HP 9100 had 32K of ROM on a 16-layer PC board
> using this method.

Some Hasler (a Swiss co.) leased telegraph message switching systemss M150
had that too. I designed some cards with DIL switches, After 1975 I think.

Julian Stacey: BSD Unix Linux C Sys Eng Consultants Munich http://berklix.com
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