OK, so the client creates a list in memory or in a file and refreshes it manually.

i didnt think it actually scanned the folder each time.

for the exception of limeware (due to its non-native coding) most of the clients (morpheus, bearshare, etc..) load fairly quickly. I'm assuming each load of the program must create a new list, or atleast refresh the list. how do they get all the file attributes (name, size, etc..) so quickly?