On September 20, 2011 at 02:00 henry@AegisInfoSys.com (Henry Yen) wrote:
A few (dozen) years ago, I was treated to a interesting demonstration where a coworker poured an oily fluid containing tiny metallic flakes on a patch of tape. The "bits" on the tape could be clearly seen by the naked eye, and could be decoded (ever so slowly!) using a magnifying glass.
Magnetic Tape Developer, you can still buy it (see link below). I remember playing with the stuff back in the days when punch cards were still your friend. I suppose it wouldn't be that hard to make your own but I think the liquid was a fast-drying light solvent or CFC, not oily, so it'd dry, you could read it, and then shake/wipe/dust it off. It was supposedly handy for recovering physically mangled tapes, it wasn't that rare for a tape to just get jammed in a drive and get so crumpled it wouldn't go thru a drive any more and you didn't have a backup tho usually at that point you dug out the original punch cards and re-created the data set or whatever, had the data re-keyed (that means punched back onto punchcards, or even key-to-tape, from its pencil+paper source) because using tape developer would be too expensive in terms of people-hours. Or you just applied to law school and hoped for the best. http://www.cardserv.asia/joomla/index.php?option=com_content&view=article&id=21&Itemid=10 or http://tinyurl.com/6kak4o7 -b