whatdoyouwant

I’m an old man, too long out of school.  I wonder why I keep trying to invent and reinvent my own filing system of tags, subjects, file names, folder names, etc. There have been a host of highly developed pre-digital filing and retrieval systems in every kind of discipline, legal, medical, technical, business, library, science and even art.  Anyone know of a pre-digital classification system that has been put into to digital use? Even into an app?