Ray Shahan asks:
>What about an MPE shell for UNIX or LINUX?

I think you need three parts to move MPE to *nix.  First you would need the
file system.  This would give you the record oriented access, file labels
and transaction management not in standard *nix.  Once you have this, you
can start to implement Image, KSAM, message files, circular files, etc.
Second you would need the shell.  All shells are just programs, but an MPE
shell would have to implement file equations, system variables, command
parsing, redirection, program execution, etc.  You would not have to
implement the POXIX shell.  ;-) Finally, It would be nice to have an
emulator that would run MPE binaries.  I was thinking along the lines of a
Virtual MPE machine.  This would read/link/run MPE binaries along with the
libraries and execute them in a protected space.  This would allow one to
run current programs without recompiling.  Eventually, in order to do new
development, one would have to reimplement the current run-time libraries
for each development environment (Cobol, f90, C, SPLash, Image, System
Intrinsics, etc.)  That might be a large task.  One may argue that a MPE
needs to define a virtual layer of functionality to make it easier to port
to new hardware as it becomes available.  I am no MPE internals expert and
have no idea how hard that would be.  But now would be a good time to do it
while HP is maintaining the PA-RISC code for the next five years.

I have been looking at the Linux side of some of these issues.  I got a
Linux File Systems and Linux Internals book for light reading over the
holiday.  (Mental note to self, Get a life.)  But again, I really have no
clue about the MPE internals.  To get some information about writing your
own file system, Linux has an interface for a virtual file system called
VFS.  If your home grown file system follows this interface, you allow
access to other Linux programs.  For the gory details see:
http://www.linuxdoc.org/LDP/lki/lki-3.html  As for shells, the best you can
do is look at other's code.  There is a link of Shells here:
http://www.linuxlinks.com/Software/Shells/ And here is a simple .cc program
shell (it's just text):
http://www.csclub.uwaterloo.ca/u/d2moser/projects/mush/simple_shell.cc

I personally think that if HP made this an add-on product that moved MPE
users to HP-UX, that would smooth some ruffled feathers.  I would still like
to see the same product on Linux for those who want to avoid vendor lock-in
and to make it easier for Alfredo to carry his MPE machine around the globe.
Alfredo?  Hell, let's face it, who wouldn't love to carry their MPE machine
around with them?

Again, it's just a thought.

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