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From: John H Meyers on 29 Mar 2008 18:59
On Sat, 29 Mar 2008 17:25:38 -0500:

> I neglected to mention that I would like a menu label builder program
> for my HP 49g+. I assume the program Raymond Del Tondo referred to
> will not work on the HP 49g+ because it uses a different processor.
> Is that correct?

The architecture of the HP49G+/50G series calculators
emulates the original HP "Saturn" processor,
in a lower-level system which is transparent to the user.

Thus, the platform does not give the user a new ARM-based computer
to play with, but gives instead a continuation of the same
original "RPL" calculator operating system
(with enhancements, of course, in Filer, CAS,
and new hardware such as larger screen, USB, and SD cards).

The independent "HPGCC" project is, on the other hand,
based on "breaking through" the existing barrier
between the "hidden ARM OS" and the emulated original "Saturn,"
in effect giving you a new platform.

If some of Raymond's programs are not portable to the 49/50 series,
it is because of differences between series
even in the "Saturn" level OS,
which also exist in parts of the OS which Raymond himself rewrites.

What direction would the series have taken if Raymond
had been playing on Bill Wickes' original all-star team? ;-)

Just tunnel into any nearby parallel universe to find out.

Best wishes from http://www.mum.edu
and http://www.maharishischooliowa.org

..
From: mnhollinger on 29 Mar 2008 21:21
On Mar 29, 6:59 pm, "John H Meyers" <jhmey...(a)nomail.invalid> wrote:
> On Sat, 29 Mar 2008 17:25:38 -0500:
>
> > I neglected to mention that I would like a menu label builder program
> > for my HP 49g+.  I assume the program Raymond Del Tondo referred to
> > will not work on the HP 49g+ because it uses a different processor.
> > Is that correct?
>
> The architecture of the HP49G+/50G series calculators
> emulates the original HP "Saturn" processor,
> in a lower-level system which is transparent to the user.
>
> Thus, the platform does not give the user a new ARM-based computer
> to play with, but gives instead a continuation of the same
> original "RPL" calculator operating system
> (with enhancements, of course, in Filer, CAS,
> and new hardware such as larger screen, USB, and SD cards).
>
> The independent "HPGCC" project is, on the other hand,
> based on "breaking through" the existing barrier
> between the "hidden ARM OS" and the emulated original "Saturn,"
> in effect giving you a new platform.
>
> If some of Raymond's programs are not portable to the 49/50 series,
> it is because of differences between series
> even in the "Saturn" level OS,
> which also exist in parts of the OS which Raymond himself rewrites.
>
> What direction would the series have taken if Raymond
> had been playing on Bill Wickes' original all-star team?  ;-)
>
> Just tunnel into any nearby parallel universe to find out.
>
> Best wishes fromhttp://www.mum.edu
> andhttp://www.maharishischooliowa.org
>
> .

So the ARM OS uses different code to give the user the same functions
as the original HP "Saturn" processor?
Why did HP choose to use the ARM OS and why did they deem that it
remain hidden?
From: TW on 29 Mar 2008 21:55
> So the ARM OS uses different code to give the user the same functions
> as the original HP "Saturn" processor?

Not exactly. Some of the key functions actually call ARM routines
that greatly speed up operation. Things like garbage collection can
happen many times a second, so that is a routine that was replaced
with an ARM version.

The rest of the system is an EMULATOR that runs essentially the same
OS that was found in the 49G. As far as code goes, most programs are
blissfully unaware that they aren't being run on native hardware.

> Why did HP choose to use the ARM OS and why did they deem that it
> remain hidden?

The reason for this is simple - time and money. It was much quicker
and more economical to release an upgraded and slightly faster version
then to spend years developing something new. It also meant that
essentially all of the stuff on hpcalc.org would run on the new
unit.

HPGCC launhes out of the emulation, runs directly on the processor,
and returns to the emulator.

TW

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