[TUHS] speak and speech synthesis

[Douglas McIlroy via TUHS]

> Also, Doug, you wrote technical report 14, which seems canonical about
> how speak worked. Is that the best source you or anyone else knows of
> vis a vis v6's implementation?

That''s the only documentation I know of. I also have C source and
driver tables for
several points in time. I cam pass them to tuhs if needed.

Doug

On Tue, Sep 15, 2026 at 12:47 AM Will Senn via TUHS <tuhs at tuhs.org> wrote:
>
> In a similar investigation to my graphics dive, this time into speech
> synthesis, I found that |/dev/vs| talks to the synthesizer through a
> DC-11. I’m trying to determine the interrupt/vector assignment for that
> device—specifically the Federal Screw Works Votrax interface.
>
> There is quite a bit of useful material scattered across UNIX V4 through
> V6. From that, I can reconstruct the system generically: add the |vs|
> driver to the kernel, create |/dev/vs|, add PCM audio support to SIMH,
> and translate the historical phoneme stream into approximate speech
> based on what can be pieced together from the source and documentation.
> This "should" work and get speak working...
>
> I’d prefer, though, to reproduce the original interface somewhat more
> faithfully. The V4/V6 |vs.c| sources give the CSR address (|0174150|)
> and the receive/transmit interrupt routines (|vsrintr| and |vsxintr|),
> but I haven’t yet found the actual interrupt vector assignment used for
> the Votrax/DC-11 installation.
>
> If anyone has an old kernel configuration, |mkconf| entry, low-core
> |l.s|, hardware note, or other documentation showing how the Screw Works
> Votrax interface was actually vectored, I’d be very interested in seeing it.
>
> Also, Doug, you wrote technical report 14, which seems canonical about
> how speak worked. Is that the best source you or anyone else knows of
> vis a vis v6's implementation?
>
> Thanks,
>
> Will
>