1. HSM was also known internally within Compaq/Digital as Ninja.

2. Another reason why AdvFS has a two-layer structure was because it was once a design requirement to support other non-POSIX file systems on top of the BAS (like VMS or MS-DOS). These requirements were never implemented.

3. A cluster in AdvFS is a set of contiguous blocks. The default cluster size is two disk blocks, or 1K.

4. The on-disk structure was (and still is) called mega-version in deference to the fact that AdvFS used to have the moniker of the megasafe file system (MSFS).

5. This number is the birthday of the original architect of AdvFS, Christian Saether (Nov 11, 1958).

6. In fact, Millsap (1992) specifically states that one of the "necessary conditions" to consider using raw disk is the unavailability of a direct I/O feature from the operating system.

7. The Tru64 UNIX 5.0 fstab(4) reference page refers to the "DirectIO" option; however, this is not implemented and will not work. The page will be corrected in a future release.