Adobe bridge creates "Adobe Bridge Cache.bc" and "Adobe Bridge Cache.bct" - which can be assigned to a global thumbnail file or can reside in the directory containing the images. If you have multiple directories (for example, I just shot six theatre productions and each production is in it's own directory), bridge can walk all of the sub-directories and create the appropriate .bc and .bct files in each directory.
Presently, before I create by backup DVDs I run Adobe Bridge to create these thumbnail files. After they are backed up to DVD, the access speed is quite excellent.