In the vt100, setup menu “B” had an interlace on or off setting. I just looked it up.
Sent from my iPhone > On May 20, 2024, at 10:51, Paul Koning via cctalk <cctalk@classiccmp.org> > wrote: > > > >> On May 20, 2024, at 1:37 PM, Wayne S via cctalk <cctalk@classiccmp.org> >> wrote: >> >> Young , hah. No i’m old 70. >> The pc monitors, not Tv, always had a setup menu. Even the Vt100 series let >> you choose interlace if you needed. > > VT100? I don't think so. And yes, it has a setup menu, but that's setup of > the terminal functionality, not the monitor part. > > The earliest monitors could only handle one format. A major innovation was > "multisync" where the monitor would determine the horizontal and vertical > sweep rate and line count, and display things the right way. The first PC I > owned had one of those, and as far as I can remember it had nothing that one > would call a "setup menu". > > The reason interlace matters is not the very slight slope of the scan line in > analog monitors, but rather the fact that alternate frames are offset by half > the line spacing of the basic frame, so each frame sweeps out the gaps in > between the lines scanned by the preceding frame. It matters to get that > right, otherwise you're not correctly displaying consecutive rows of pixels. > In particular, when doing scan conversion (from analog format to a digital > X/Y pixel raster) you have to offset Y by one every other frame if interlace > is used, but not if it isn't. > > paul > >
