Does anyone have advice to help my friend who has a few-hundred-k backup ebooks on a drive somewhere? I realize a calibre-style interface for this many books is

Does anyone have advice to help my friend who has a few-hundred-k backup ebooks on a drive somewhere? I realize a calibre-style interface for this many books is out of the question, but I always felt bad that he can't easily access the material because just doing an ls or opening the directory in the file manager slows his system down. Has anyone found any solutions for this? Indexing the content isn't required, but would be an awesome plus.