On Wed, Jun 6, 2018 at 9:20 AM, Toby Thain via cctalk <cctalk@classiccmp.org > wrote:
> On 2018-06-06 9:48 AM, Noel Chiappa via cctalk wrote: > > (BTW, the VT11 in DEC's GT40 used bit maps for its built-in character > geneator, > > and the hardware did tiny raster zones to display them!) > > As does the PDP-1 (point plotting, 5x7 I think). > Some variants of the Type 30 display, used on the PDP-1 and other early DEC computers, included a Type 33 character generator option, which works as you describe. The computer sends two 18-bit words, which are interpreted as a 5x7 bitmap, with the leftover bit used to shift the character slightly for a subscript. The Type 30G display has the Type 33 character generator as a standard feature. The PDP-1 at the Computer History Museum has a 30G, but the character generator is not completely working. I suspect that most PDP-1 installations did not have the character generator. There is not known to be any surviving PDP-1 software that used the character generator; I wrote simple test programs we used to attempt to debug the hardware.