On 8/10/2019 1:56 PM, Paul Birkel via cctech 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 > >
I wonder if, maybe, it used the same protocol as the GT40, which also had a boot-over-serial line capability. JRJ