10 Aug
2019
10 Aug
'19
3:03 p.m.
The VT20 design team was, iirc, John Kirk for the video, and me for
the Unibus interface in the first version. The one with the slick
one shown here,
http://bitsavers.org/pdf/dec/terminal/vt20/vt20_2.jpg
The /05 based package was after my time, I don't remember much about
how it was deployed.
The boot device called using the boot strap board was variable, and I
don't recall anything beyond an RK05
based system (booting the RK) for the versions in the lab on 1-2 in the mill.
It was for the Typeset 11 team, and then the TypeSet.DecSet team/Product line.
bob
On Sat, Aug 10, 2019 at 2:56 PM Paul Birkel via cctech
<cctech at classiccmp.org> wrote:
The DEC VT20 terminal apparently included a PDP-11/05 with a direct mapped
character display and was intended for text editing and typesetting. It
seems to have been followed by the VT21, and then VT71/VT72, all three based
on an LSI-11 (KD11-F). There's a real lack of documentation about these
online, although the VT72 does have a print set.
Apparently the VT20 used the M792-YK as its bootstrap; the Field Guide is
silent regarding the boot device and M792 documentation stops earlier in the
series of variants.
According to the VT72 print set, it used the MRV11-VC (M9942-YC; described
in the Field Guide as a "bootstrap/diagnostic module") for its bootstrap but
is also silent regarding the boot device. In interestingly, the Field Guide
also describes a MRV11-AA (M7942-TB) as a "M7942 with VT52 emulator, VT71
bootstrap".
For async. communications the VT20 used a DL11-B (M7800 (EIA)). the VT72 a
DLV11-F (M8028).
Looking in a DEC "Options and Modules" listing I see VT20 bundles including
Typeset-11 and DECset-11, and it appears that the VT20 could be configured
with two displays & serial lines in a single 11/05.
So . is the boot device in these systems the remote host via the serial
line? What protocol would that have been? Something native to Typeset-11
and DECset-11?
paul