Purely historic question: VT200 text graphic programming

[Grant Edwards]

On 2011-03-11, Martin Gregorie <martin at address-in-sig.invalid> wrote:

> BTW, there was no such thing as a VT-200 - there was a VT-220 text 
> terminal (which I think the OP was remembering) and the VT-240 and
> 241 terminals, which were totally different graphics terminals that
> accepted Tektronics graphics commands: comparing a VT-220 to a
> VT-240/241 would be like comparing an Epson dot-matric printer to an
> HP 7485 plotter!

The 220 and 240/241 weren't fundamentally different display
technologies they way a dot-matrix differs from a pen-plotter.  Both
were raster-scan CRT tubes (AFAICT, they used identical CRT tubes and
driver hardwar). When used in text mode, the 240 wasn't really any
different than the 220.  But, the 240 also supported a graphics mode
that allowed apps to draw using vector commands).  I remember writing
an app using the ReGIS command set to draw a clock with a moving
second hand on a 240.

Comparing a vt220 to a vt240 is like comparing a black-and-white epson
9-pin dot-matrix printer that can't do graphics with a balck-and-white
epson 9-pin dot-matrix printer than can do graphics.

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