Purely historic question: VT200 text graphic programming

[Martin Gregorie]

On Fri, 11 Mar 2011 19:32:53 +0000, Grant Edwards wrote:

> 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.

Sorry if I wasn't clear: I was intending to compare APIs rather than the 
display mechanisms - I am aware that both text terminals and vector 
graphics terminals are raster devices, not vector like oscilloscopes.  
What I was getting at is that the API used to cause graphics or text to 
be output on a dot-matrix printer is totally unlike that used to draw to 
same representations on a pen plotter.


-- 
martin@   | Martin Gregorie
gregorie. | Essex, UK
org       |