[Info-vax] Itanium emulator (was Re: OpenVMS.Org quick poll)

[Stephen Hoffman]

On 2012-08-20 14:37:58 +0000, Keith Parris said:

> On 8/17/2012 8:04 PM, John E. Malmberg wrote:
>> The
>> SKI emulator would have to be further enhanced.  Based on the
>> description on the project page, the SKI emulator appears to be only
>> emulating the user mode instructions, not the stuff needed for the VMS
>> kernel to run.
> 
>  From http://ski.sourceforge.net/, first paragraph:
> "ski supports the full instruction set of the architecture, including 
> privileged instructions and associated semantics."

Read further on that page; like the comment that the Software 
Developer's Manual (SDM) 2.2 stuff may not be supported.  SDM 2.3 is 
current, and what the future Itanium processors (those currently 
constructed of unobtainium) might bring along is not known.  SDM 2.2 
was from 2006 IIRC.

When last I looked, Ski was an instruction emulator, and not a system 
emulator; it wasn't emulating I/O devices, providing virtual 
networking, etc.  (This may be what John was referring to.)

I do appreciate the "We've 'papered over' some fixes for the various 
Linux syscall routines. What we need to do is go over all of them to 
make sure we're not lying to userspace *too* badly." humor that's one 
of the two currently-open bug reports against Ski, too.   And given 
there are a total of two (old) bugs listed, which doesn't make it look 
like a very active project.  Last update to Ski predates Tukwila, too; 
it's definitely not exactly an active project.

Put another way, Ski looks to be a non-starter as an emulation 
platform.  It's, well, dead.

Could somebody pick it up?  Sure.  The GPL2 also means there'll be some 
wrinkles around a commercial provider basing any products on Ski, too.

> 
>> Now you have a x86 VMS emulator
>> that can run Alpha, IA64, and native X86-64 all at the same time.
> 
> Given that Simh VAX emulation code is well-proven and readily available 
> in open source form, you could use the same approach to execute VAX 
> executable images as well.

True.   Though backporting code to 32-bit and V7.3 APIs might be more 
pain than backporting to Alpha, where that's available.


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