Bob queries:
> I remember that a long time ago (MPE IV) that there was a
> performance penalty for running programs that lived on
> private (user) volumes.

MPE/V's "Private Volumes" were a bit of a kludge hung on the side of an OS
which was not originally designed for them.

MPE/iX's "User Volumes" facility was designed into the OS from day 1, and
there is no penalty that I'm aware of for using them.

On MPE/V, you had some information on normal system discs, and some on
private volumes, and there was extra work to get to the private volumes
stuff.  On MPE/iX, *everything* is in a "volume set".  Your user volume set
is just like the system volume set (except that it probably has a shorter
name :-)

Generally there is a performance *advantage* to creating user volume sets on
MPE/iX, since Transaction Management is done on a volume set by volume set
basis and having more than one volume set means that your XM I/O is spread
out across multiple disks and your user data XM does not interact with
system XM stuff.

G.