12 Dec
2025
12 Dec
'25
8:49 p.m.
It's been a while since i last wrote to the list. I have been reading up a
lot on early cnc systems.
While recently picking up some left over tech from a shutdown machine shop,
spotted a early cnc system with some kind of minicomputer attached. Looked
to have some kind of tape drive and paper tape punch. It looked like it was
stored under a leaky roof, ball of rust, it looked too far gone to salvage
anything useful.
Sadly phone was dead at the time and i did not get pictures.
Reading up on wikipedia, Data General Nova and Dec PDP 11 mini computers
are mentioned as used in early cnc.
Are there any surviving cnc systems, details, or software for the pdp 11?
I am interested to know a bit more how the hardware was interfaced. I have
pdp 11/34 systems for example, not sure if the external machine hardware is
directly wired into the unibus with a/d cards, or if some kind of external
hardware controller is driven by the pdp.
I have not found much info on any software used for this purpose.
Any accounts of how this worked or other interesting stories / info much
appriciated.
Thanks,
Devin D'Amico
12 Dec
12 Dec
9 p.m.
I think the answer would be with what kind if interface was available on the cnc machine.
Weren’t most of them just serial ?
The pdp could be made to interface to anything.
Sent from my iPhone
On Dec 12, 2025, at 18:50, devin davison via cctalk
<cctalk(a)classiccmp.org> wrote:
It's been a while since i last wrote to the list. I have been reading up a
lot on early cnc systems.
While recently picking up some left over tech from a shutdown machine shop,
spotted a early cnc system with some kind of minicomputer attached. Looked
to have some kind of tape drive and paper tape punch. It looked like it was
stored under a leaky roof, ball of rust, it looked too far gone to salvage
anything useful.
Sadly phone was dead at the time and i did not get pictures.
Reading up on wikipedia, Data General Nova and Dec PDP 11 mini computers
are mentioned as used in early cnc.
Are there any surviving cnc systems, details, or software for the pdp 11?
I am interested to know a bit more how the hardware was interfaced. I have
pdp 11/34 systems for example, not sure if the external machine hardware is
directly wired into the unibus with a/d cards, or if some kind of external
hardware controller is driven by the pdp.
I have not found much info on any software used for this purpose.
Any accounts of how this worked or other interesting stories / info much
appriciated.
Thanks,
Devin D'Amico
9:30 p.m.
On Fri, Dec 12, 2025 at 9:50 PM devin davison via cctalk
<cctalk(a)classiccmp.org> wrote:
It's been a while since i last wrote to the list.
I have been reading up a
lot on early cnc systems.
While recently picking up some left over tech from a shutdown machine shop,
spotted a early cnc system with some kind of minicomputer attached. Looked
to have some kind of tape drive and paper tape punch. It looked like it was
stored under a leaky roof, ball of rust, it looked too far gone to salvage
anything useful.
About 15 years ago, we had a Bridgeport Series II CNC mill with an
original DEC LSI-11 processor board stuffed into a slot in
all-Bridgeport hardware. In addition to manual operation on control
switches, it had a Remax paper tape reader and a serial port to slurp
up G-code.
Because the PDP-11 only had 16K of RAM, you had to either run jobs
from paper tape (which nobody wanted to punch in this century) or
dribble the G-code in a manner described as "drip feeding". Given
that a lot of modern designs coming out of your CAM engine are upwards
of a megabyte, that's a lot of dripping.
In the end, it was more trouble than non-technical folks wanted to
deal with so it was scrapped for the price of scrap steel. I was
allowed to strip whatever I wanted - I kept the PDP-11 CPU and the
Remex reader.
I have no idea specifically what programs were used in the 1970s to
generate the G-code (though G-code can and was written up by hand).
-ethan
13 Dec
13 Dec
1:44 a.m.
30 years ago we had a G-code tape editing system for our Trumpf punch press
that was an 11/03 and a Teletype. When they scrapped the punch press I
didn't take the 11/03. :-(
On Fri, Dec 12, 2025, 10:32 PM Ethan Dicks via cctalk <cctalk(a)classiccmp.org>
wrote:
On Fri, Dec 12, 2025 at 9:50 PM devin davison via
cctalk
<cctalk(a)classiccmp.org> wrote:
It's been a while since i last wrote to the
list. I have been reading
up a
lot on early cnc systems.
While recently picking up some left over tech from a shutdown machine
shop,
spotted a early cnc system with some kind of
minicomputer attached.
Looked
to have some kind of tape drive and paper tape
punch. It looked like it
was
stored under a leaky roof, ball of rust, it
looked too far gone to
salvage
anything useful.
About 15 years ago, we had a Bridgeport Series II CNC mill with an
original DEC LSI-11 processor board stuffed into a slot in
all-Bridgeport hardware. In addition to manual operation on control
switches, it had a Remax paper tape reader and a serial port to slurp
up G-code.
Because the PDP-11 only had 16K of RAM, you had to either run jobs
from paper tape (which nobody wanted to punch in this century) or
dribble the G-code in a manner described as "drip feeding". Given
that a lot of modern designs coming out of your CAM engine are upwards
of a megabyte, that's a lot of dripping.
In the end, it was more trouble than non-technical folks wanted to
deal with so it was scrapped for the price of scrap steel. I was
allowed to strip whatever I wanted - I kept the PDP-11 CPU and the
Remex reader.
I have no idea specifically what programs were used in the 1970s to
generate the G-code (though G-code can and was written up by hand).
-ethan
9:39 a.m.
On 12/12/25 20:49, devin davison via cctalk wrote:
It's been a while since i last wrote to the list.
I have been reading up a
lot on early cnc systems.
While recently picking up some left over tech from a shutdown machine shop,
spotted a early cnc system with some kind of minicomputer attached. Looked
to have some kind of tape drive and paper tape punch. It looked like it was
stored under a leaky roof, ball of rust, it looked too far gone to salvage
anything useful.
Sadly phone was dead at the time and i did not get pictures.
Reading up on wikipedia, Data General Nova and Dec PDP 11 mini computers
are mentioned as used in early cnc.
Are there any surviving cnc systems, details, or software for the pdp 11?
One early iteration of the Bridgeport BOSS CNC control used
an LSI-11 with all the CNC program in ROM. Later versions
used a 68000.
I have an Allen-Bradley 7320 CNC control, that uses their
7300 16-bit CPU. I replaced that unreliable system with a
PC running LinuxCNC back in 1998 and never went back. The
7320 has been taking up space in my basement since then, but
I don't have the heart to scrap it.
Jon
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days inactive
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days old
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5 participants
participants (5)
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devin davison -
Ethan Dicks -
Jon Elson -
Michael Thompson -
Wayne S