Note also "quick". With CGA I remember when I issued a "DIR" in the DOS prompt I could follow the lines with my eyes as the line of output was appended. It took maybe more than a second to scroll through one full screen. Talking about speed :). Of course this didn't happen with some fancy graphics card, which was probably the main culprit in the lack of speed.
Csaba On Mon, Sep 9, 2013 at 1:40 PM, Michael Chaney <[email protected]>wrote: > The "quickly flying light dot" is how the picture was drawn on a CRT, so > it didn't have to do anything special. The light pen simply reported to > the video card "I saw the dot", and the board would then store somewhere > the exact x/y position that it was drawing when the pen fired. This is how > the gun for the NES worked, as well as various other such instruments for > other computers. I remember the C64 having such, also. > > It probably wasn't a great idea to stand that close to a CRT for extended > periods of time. > > Michael > > > On Mon, Sep 9, 2013 at 3:00 PM, Jack Coats <[email protected]> wrote: > >> The other day I ran into my doc's about CGA displays, including the >> lightpen input. The light pen was a photo transistor and a switch >> that signaled the CGA board the light pen was pressing on the glass >> screen. The CGA display actually did the scanning (with a quickly >> flying 'light dot' to find the pen position) and reported it back to >> the computer through the CGA display card. >> >> Now back to your daily dose of non-bone-kives-and-bear-skin-technology. >> >> -- >> -- >> You received this message because you are subscribed to the Google Groups >> "NLUG" group. >> To post to this group, send email to [email protected] >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/nlug-talk?hl=en >> >> --- >> You received this message because you are subscribed to the Google Groups >> "NLUG" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > > > -- > Michael Darrin Chaney, Sr. > [email protected] > http://www.michaelchaney.com/ > > -- > -- > You received this message because you are subscribed to the Google Groups > "NLUG" group. > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/nlug-talk?hl=en > > --- > You received this message because you are subscribed to the Google Groups > "NLUG" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/groups/opt_out. > -- -- You received this message because you are subscribed to the Google Groups "NLUG" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/nlug-talk?hl=en --- You received this message because you are subscribed to the Google Groups "NLUG" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
