If you post a wishlisted book, there's only one person who wants it ; the person lets it time out, and in the meantime several of the same book are posted, do you go to the back of the FIFO line or would you become #1?  Thanks.  Pat

Since the FIFO position is not visible to the member who posted the book, the only ones who know for sure are the PBS programmers ... but if I were designing this system, I would go by the date the book was originally posted. We know they do have this data because it shows up on your bookshelf.

Usually in a system like this one there's no reason to store a position like "3 of 10". For a computer it's much easier to calculate the 3 and the 10 when you need to display them than it is to update the record of everyone who's in line each time the line moves.

If the book request times out, you return to the sendout FIFO line in the order you were in before.  Presumably #1, unless someone else who was on Vacation Hold or something is the actual #1 slotholder and they came back, and you'd default to #2 when you returned in that case.  You don't go to the back of the sendout FIFO line.

Thanks.  Pat