> hoss karoly or charley wrote: > > how about the metal stickers supplied with the floppy disks ? > > it's a thin metal layer with adequate glue to keep it anywhere > > Not quite anywhere. For instance, I've never been able to get them to > stick to the floppy disks. Heh--I see I'm not the only one. Personally, what I used to like for write- protection was "Scotch" tape until I discovered that on newer drives it didn't work. Oh well... I wonder whether anyone produces any materials that are transpar- ent to UV but opaque to anything else. I have confirmed that a mini-maglite (flashlight) will stop a 16C622 if it is aimed from a distance of about three inches and it will start to affect the comparators shortly before that. Room light seems to affect the comparators as well, though in this particular application I was using a high-impedance (about 1meg) input and so the light may just have changed the input impedance. Using the comparator as a 0-5v DAC, the light affected the count by about 1% (about 50mv). For some app- lications this may not be too bad; for others, this would be crippling.