DEC PDT-150 software

Ethan Dicks ethan.dicks at
Mon Jul 11 12:12:27 CDT 2016

On Sat, Jul 9, 2016 at 4:54 PM, Brendan McNeill <brendan at> wrote:
> Greetings
> I have a restored and (I think) functional PDT-150 with dual 8” floppy drives but no software.  I do have some blank 8” diskettes but no real means of transferring an operating system or (say) a word processing program onto them.

This reminds me to ask, since I also have a PDT-150... there's
vtserver for larger machines
( - 192K of RAM
required) that can be used to image 8" floppies on a bare machine.
Every few years, I keep tossing around the idea to bang out a
less-feature-rich vtserver client with only one device driver loaded
and target a machine with 56Kbytes (or 60Kbytes - PDT-150) but I've
never sat down to check the level of effort, or if it's just worth
starting from scratch with an RX (or RL or RK) target and make a new
app and client.  The advantage of reusing the vtserver server part is
that it's been in use for long enough to find the obvious bugs, and
the limitation of 16-bit block counts (32MB) isn't an issue for most
1970s media, even up to RK07s.

Once you have a working RT-11 system, things like Kermit are handy
enough for moving files, but I think we are still lacking in the
"bootstrapping a small machine" department.  For me, since I have
alternatives, the "simpler" option is to turn a MicroPDP-11
(w/256Kbytes or more) into an RX01/RX02/RL01/RL02 imaging machine and
just use vtserver.  I still dream of a bare-metal solution for 64KB
machines, since that _is_ viable for a small RT-11 rig.


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