apple moving to x86
John Baldwin
jhb at FreeBSD.org
Fri Jun 10 16:41:26 GMT 2005
On Jun 9, 2005, at 7:21 PM, Stephen Hurd wrote:
> John Baldwin wrote:
>
>>
>> On Jun 8, 2005, at 10:30 PM, Stephen Hurd wrote:
>>
>>>
>>>> As there is FreeBSD port to the PowerPC and its peripherals, this
>>>> machine will make a very interesting target for FreeBSD: combine
>>>> the x86 code base with the PowerPC drivers and get a real hot
>>>> machine.
>>>
>>>
>>> The *really* hot machine is going to be the OSX ABI supported under
>>> FreeBSD and running Aqua. I betcha this happens FAST.
>>
>>
>> I doubt it would be fast at all if it even happens. Unlike Linux,
>> svr4, and ibcs2, OS X is not just a POSIXish UNIX kernel. It also
>> includes mach so there would have to be a lot of emulation to support
>> that. OS X also tends to define its interface not at the kernel
>> syscall level but at the library API level (from what I have heard),
>> which means that it might require having custom versions of the base
>> system frameworks ala Wine which would be an enormous amount of work.
>>
> But the ABI support is about emulating the kernel ABI, not about
> emulating the kernel. Since the *nix userland is mostly FreeBSD
> afaik, the ABI must be pretty darn close already. If the interface is
> via libraries, that makes it MORE likely not less to happen fast...
> unless I misunderstand something. ABI emulation doesn't replace the
> libraries. You'd still need a copy of OSX to run OSX binaries that
> used the shared libs (Just like all the other ABI emulations).
Two things. First, OS X's kernel ABI includes things like Mach IPC,
etc. that would require a good bit of code to emulate. Secondly, since
OS X's ABI is at the library level, they are freer to change the kernel
ABI within a 10.x "branch" making it harder to get an ABI that will
work with all versions of Panther or Tiger for example.
--
John Baldwin <jhb at FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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