Nifty feature in VMS alias mechanism

[Joe Buck]

In article <1122 at ttrdc.UUCP> levy at ttrdc.UUCP writes:
>(Which prompts another aside on VMS; why oh why is there a SET FILE/ENTRY
>under VMS if DELETE-ing the extra entry blows away the file data itself,
>leaving any other entries for that file invalid?  Why isn't a link count
>kept a la the UNIX (TM of AT&T) OS even if VMS doesn't have inodes?)

VMS does have the equivalent of inodes; they're blocks in the index
file, pointed to by the FID.  The index file looks very much like the
inode list of Unix.  It would take very little work to add a link
count to the index block and change $DELETE to Unix behavior.  There
are a couple of barriers to making the behavior identical -- for one
thing, the filename (but not the directory name) is stored in the
index block, but this is mostly relevant when a lost file is
recovered (because, say, a user blew away a directory entry with SET
FILE/REMOVE).  But VMS could handle links properly without that much
effort, and users wouldn't notice the change.
-- 
- Joe Buck 	{ihnp4!pesnta,oliveb,nsc!csi}!epimass!jbuck
  Entropic Processing, Inc., Cupertino, California