[Info-vax] Alpha emulator for OSX

[johnwallace4 at yahoo.co.uk]

On Monday, 8 February 2016 13:18:44 UTC, Johnny Billquist  wrote:
> On 2016-02-08 13:10, johnwallace4 at yahoo.co.uk wrote:
> > On Monday, 8 February 2016 10:20:06 UTC, li... at openmailbox.org  wrote:
> >> On Mon, 8 Feb 2016 00:10:48 -0800 (PST)
> >> Arie de Groot via Info-vax <info-vax at rbnsn.com> wrote:
> >>
> >>> Op donderdag 4 februari 2016 07:50:15 UTC+1 schreef li... at openmailbox.org:
> >>>> On Wed, 3 Feb 2016 21:32:52 -0600
> >>>> "Craig A. Berry via Info-vax"
> >>>>
> >>>> What commercial Alpha emulators run on anything but Windows and 64-bit
> >>>> Linux?
> >>>>
> >>>
> >>> vtAlpha runs on X86 without the need for an extra OS like Windows or
> >>> Linux. Or OSX for that matter. Everything you need is included in the
> >>> product. Install it on an X86 host (or a virtual equivalent in any of the
> >>> popular VM products) and you are set. If you like to know more:
> >>> vtalpha.com.
> >>>
> >>> For the record: we are the makers of vtAlpha. This is not a shameless
> >>> plug but I felt all alternatives should be mentioned.
> >>>
> >>> Arie de Groot
> >>> AVTware
> >>
> >> Hi, thanks for the info. I didn't respond to Vaxman's post earlier because
> >> I didn't want to get involved when I have no money to spend on this (no
> >> commercial need).
> >>
> >> I am a VMS hobbyist (barely) and not looking for a commercial solution but
> >> I was interested in this issue for two reasons. One as a hobbyist I would
> >> like to be able to run VMS Alpha which I currently cannot because I don't
> >> have Windows or 64 bit Linux. The second is I think being able to host an
> >> emulator on non-Intel hardware would be very useful. And sometimes that
> >> trickles down into a non-commercial freebie for hobbyists.
> >>
> >> For example, I have been advocating VMS should be moved to POWER hardware
> >> instead of Intel. A platform independent Alpha emulator would make that
> >> more possible. SPARC is also a good platform. I think more choices are
> >> better and running a premium OS (VMS) on premium hardware is better than
> >> running it on fast/cheap/bad hardware (Intel).
> >>
> >> I understand the value of running bare metal and that is also obviously a
> >> very smart and good option. More choices are almost always better! Thanks
> >> for the info.
> >>
> >> --
> >> RSA 4096 fingerprint 7940 3F02 16D3 AFEE F2F8  ACAA 557C 4B36 98E4 4D49
> >
> >
> > You mention bare metal. Arie says "vtAlpha runs on X86 without the
> > need for an extra OS like Windows or Linux." He doesn't say "bare
> > metal" here, but the term is used on their website.
> >
> > Unless something has changed since the last significant discussions
> > I remember on this topic (several years ago), vtAlpha runs on top of
> > a cut down Linux (it'd be unrealistic to expect it to run on random
> > x86 systems *without* an underlying OS, or at least a HYPErvisor).
> 
> I know of a PDP-11 emulator that can do just that. Runs on the bare 
> metal x86. Really. No OS at all involved.
> 
> > So it may not fit everyone's definition of "bare metal". Others may be
> > perfectly happy with a setup like that. Take your pick.
> 
> Agreed. Running under Linux does not fit my definition of "bare metal".
> 
> 	Johnny
> 
> -- 
> Johnny Billquist                  || "I'm on a bus
>                                    ||  on a psychedelic trip
> email: bqt at softjar.se             ||  Reading murder books
> pdp is alive!                     ||  tryin' to stay hip" - B. Idol

I don't think I quite said that an emulator *couldn't* run on
a bare x86 (whatever one of those might actually be defined as).

I do take your point, but what I actually said was "it'd be
unrealistic to expect it to run on random x86 systems". Once the
emulator has to start coping with the variability of IO, memory
management, etc, in the unstable world of x86, life gets
tedious.

That variability (others might call it incompatibility) is part
of why people invented Hardware Abstraction Layers and such.

Put an actual OS (in full fat or in slimmed down or HYPErvisor
flavour) on top of the HAL, and life gets complicated and
potentially unpredictable, as contributors here are clearly
aware.

All good fun.