In organizing my Epicurean and other material, I am wondering if people here (especially the professional research librarians 
) have any suggestions for computer technology.
My specific question arises today in saving a PDF that covers several important topics. I'd like to "Tag" that PDF with key words so that at a later date in another program I can search by keyword and file all files everywhere related to that topic.
Also, I don't want to get tied into a specific computer operating system that would keep me from moving to another computer and having access to the tags indefinitely.
Anyone know such product?
Does anyone have experience with using Zotero or Mendeley other research assistant software do this?