CRT displays [was: computer graphics in the 1950s]

Philip Belben philip at axeside.co.uk
Mon Oct 20 14:41:08 CDT 2008


>> They actually scan to the upper left corner of each character, then 
>> sweep out the 5x7 dot matrix for that character, before adjusting the 
>> x,y deflection to the upper left corner of the next character.
> 
> I seem to recall the DEC VT11 (and thus GT40) did something similar. When 
> it displayed a character it scanned a little raster at the appropriate 
> place on the screen and used a normal dot-matrix character generator to 
> turn the beam on and off.

The Tektronix 4052 and 4006 (and presumaby 4051 and 4012) do this. 
These machines all have storage-tube vector displays, but when you want 
to display text, scan a little dot matrix of the character.  The 4052 at 
least can put this little dot matrix at any addressable point on the 
screen, not limited by the character block spacing or even (AFAIK) the 
dot matrix spacing.

(The 4014 and 4054, iirc, drew the characters in a line draw font, which 
meant they could be scrolled or rotated.  I don't have either... yet)

Philip.



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