Mike Belshe ([log in to unmask]) wrote:
 
: While portability is nice because it allows us to expand our application
: base, it is also a problem in that applications written specifically
: for UNIX are generally not optimized for an MPE environment.
 
I'll concur with the technical arguments that Mike makes,
which suggest that UNIX code ported to MPE will necessarily
run slower than it did on UNIX, unless you optimize the code
for MPE.  I will, however, offer one additional thought.
 
Virtually every example that Mike offers relates to C code
ported to MPE via POSIX.  In my experience, few UNIX
applications (at least few commercial UNIX applications) are
built this way.  It's far more likely for a commercial UNIX
application to be built on top of a portable DBMS (like
Oracle), or 4GL (of which there are dozens).  This means
that Mike's comments apply more to the porting of
application development tools (which tend to be written in C
and which may leverage POSIX) than to the porting of the
app's themselves.
 
Generalizations are always dangerous, but when you port a
4GL or other application development tool to a new platform
(such as a 3000), you are probably going to do a lot more
optimization than you will if you are porting a single
application, because you'll be able to leverage your
optimization efforts across many app's (instead of just
one).
 
Just some thoughts.....  And in the absence of any hard
benchmark data, is anybody out there running Oracle VII on
both UNIX and MPE?  Is there a discernable difference in
performance?  (I know that the engineers who did the port
wanted to make it run faster on MPE, but to date I haven't
seen any proof that they succeeded).