[TUHS] DECtapes under the UNIX room floor

[Paul Winalski via TUHS]

On Wed, May 6, 2026 at 3:59 PM Clem Cole via TUHS <tuhs at tuhs.org> wrote:

> On Wed, May 6, 2026 at 2:13 PM Phil Budne via TUHS <tuhs at tuhs.org> wrote:
>
> > I wonder: Was the VAX 11/780 the first DEC system that came with an
> > RTC/TOY clock out of the box?
> >
> Sort of.  It was not battery-backed up, which is why both VMS and UNIX
> require the time to be set.  IIRC first Vaxen to have a battery to cover
> the TOY on a power outage,  were the Mayflower machines  (uVax and
> VaxStation systems).  The J-11-based systems had a TOY, as did the 23+ (not
> the 23).
>
> On the 11/780 there was an optional battery backup available that allowed
the PDP-11/03-based console subsystem to maintain the TOY clock when the
system is powered down.  The 11/75
0 also had an optional battery backup for the TOY clock.

TOY clock battery backup was not available on the 11/730.  This prompted
Dick Hustvedt, chief VAX/VMS development engineer, to play a brilliant
April Fools prank.  On April 1 the VMS Group's 11/730 had a new
peripheral.  It was a sundial on a stand.  There was a photocell positioned
at the 12 o'clock position.  The sundial was plugged into the 11/730's
UNIBUS adapter.  On the sundial was a very authentic-looking (it was made
using the actual fonts and layout) DEC marketing brochure claiming the
device to be an "SD730 Fixed Head Solar Horologue".  This device could
detect noon and set the 11/730's TOY clock accordingly.

-Paul W.