Glenn asks:

> Stan writes:
> > I forgot to add...the other major difference is that NM code can address
> > a heck of a lot of code/data: many, many gigabytes (1 to 4 gigabytes easily,
> > and thousands of 4 gigabyte chunks with slightly more work ... far far far
> > more than HP-UX (or most any other machine)).
>
> But...but...but...How can machine instructions -- the same instructions
> used both by MPE and by HP-UX -- be compared to an OS?  Is this really
> just saying that HP-UX does not take full advantage of the underlying
> hardware??

HP-UX *barely* uses any of the addressing capability of PA-RISC.

MPE/iX uses all of it!

With MPE/iX, you can HPFOPEN/longmapped a thousand files, each of
4 GB.  Since you get back a virtual address for each file, that gives
you 4 TB of data addressability!  (Admittedly, segmented into 4 GB
chunks, and admittedly somewhat difficult to use from languages that
don't support 64-bit pointers (COBOL/iX, FORTRAN/iX, gcc, RPG/iX,
BusinessBASIC/iX)   (Said differently, only HP C, Pascal/iX, and SPLash!
can handle 64-bit pointers natively.)

HP-UX roughly looks like a 2-GB system space and a 2-GB process local
space ... sort of like a VAX ... and that's *all*.  You can't get
access to other spaces.

HP, of course, has never tried to use this addressing capability as
a competitive advantage.  After all, it might take away sales from HP-UX :)

HP has announced they're working on files > 4 GB.  One would assume that
when that ships, you'll be able to have many "large files" open at a
time...giving you many chunks of linear address space much larger than
4 GB!

Now...if only I had a TB of disk storage!  (and a way to back it up :)

--
Stan Sieler                                          [log in to unmask]
                                         http://www.allegro.com/sieler/