[log in to unmask] posted:

> Please excuse the simplicity of this question as I'm a complete MPE
> novice.  However, a large looming project which my company has put me
> in charge of will undoubtedly make me MPE experienced in no time.

No question is too simple to post. Some just provide better straight lines
than other...

First, I'll point you to: http://www.allegro.com/papers/learnmpe.html

> However, I need to have two things clarified, and since information on
> MPE is hard to find, this forum is as good as any to start with:
>
> 1)  My understanding is that there are two distinct "modes" that run on
> MPE/iX - MPE native, and POSIX.  If an MPE native app and POSIX are
> running at the same time, can they work with each other?  I've heard
> that they are completely disjoint and cannot share information.

The short answer: MPE native apps, and "POSIX apps" work together just fine.
They can share information using any mechanism you like (message files,
pipes, sockets, IMAGE databases, flat files, KSAM files, etc.).

The POSIX standard (well, the portions available on MPE) describe: a set of
OS API's (also known as "system calls"), a set of utilities, and a shell.

POSIX is *not* a "mode".  There isn't really any such thing as a POSIX
application, file, etc.

The implementation of the POSIX API's on MPE required the addition of a
hierarchical file system (HFS) of which the traditional MPE fileset was made
a proper subset, and a new layer of file security.

The HFS is *not* POSIX; it was merely required by the POSIX API's.

POSIX compliance also affects the behaviour of some traditional C library
functions (usually in very obscure ways).  Using C, you generally specify a
compile-time macro to make the libraries behave in a POSIX-compliant mannor.

> 2)  Can MPE/iX 6.x be installed on an HP9000, or will it only work on
> an HP3000?

Only on an HP3000, even though they use the same hardware.  HP will happily
change a couple of bits in a ROM for you to turn your HP9000 into a much
better HP3000, but they will also happily bill you a lot of money to do so.
Don't attempt to do it yourself, unless you like spending long periods of
time indoors with a lot of other men, if you catch my drift.

Disclaimer: this was a quick answer, dashed off in a hurry.  Watch this
thread (possibly) for more complete answers and corrections.

---
Michael D. Hensley       | mailto:[log in to unmask]
Allegro Consultants Inc. |
408/252-2330             | Visit scenic http://www.allegro.com