[OT] Can Vista run on others than x86 and x86-64

Hi,

i want to ask a OT question here since i
think, i will get the best answere here. I
remember the NT basis (NT4) being able
to run on different processor architectures,
because of the majority of the os (excluding
hal and other core components) written
in C. Are the Vista Kernel Components and/or
Usermode parts still able to run on other
architectures with a costumized kernel/hal layer
or has this definitly been dropped from the OS
architecture,...


Regards

Kerem

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Windows 2008 (Vista SP1) also has IA64 (Itanic) flavor.

 

Hi Alexander,

thanks for the information. What i was talking
about, was whether the Operating System is
still developed that way, that it can run on
exotic Processors for which compilers are
available. I mean is the Hardware Abstraction
Layer still modularizable/exchangeable as it was
on NT4,...long time ago,...

Regards

Kerem

--

 

The hardware abstraction layer was never as much of the special glue as
various authors implied. There were definitely always significant portions
of the kernel conditionalized on a per processor basis. In general the OS
is still built so it could be moved to another architecture, but like any
"portable" OS this is not a small effort. And like always with NT, there
is a little-endian byte order requirement.


--
Don Burn (MVP, Windows DDK)
Windows Filesystem and Driver Consulting
Website: http://www.windrvr.com
Blog: http://msmvps.com/blogs/WinDrvr
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Hi Don,

Yes, that was the answer i was looking for,...

I know,...

Ok, i see,...

I was asking this, because maybe someday there
will be very powerfull processor, possibly totally
different than the IA Architecture, i mean who knows,
so the operating system must be as portable as possible.
So MS ist still going the way coding the os "portable",...
Thats good to hear,...

Regards

Kerem

--
-----------------------
Beste Grüsse / Best regards / Votre bien devoue
Kerem Gümrükcü
Latest Project: http://www.codeplex.com/restarts
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"This reply is provided as is, without warranty express or implied."

 

That requirement is more than just NT. Every version of Windows ever
produced (1/2/3, 95/98/ME, NT, and even CE) requires little-endian
hardware.

Well, the Itanium is "totally different than the IA Architecture", so I'd
say that day is today.

 

Thanks for your reply,...

Regards

K.

--

 

exotic Processors for which compilers are

Windows code base was never supporting big-endian CPUs, but yes, Windows is
portable (to little-endian at least).

HAL has nothing to do with ports to other CPUs. Ports to other CPU are done
using macros in the kernel source.

HAL is about "CPU-surrounding framework" like timers, interrupt controllers,
hardware shutdown etc.

The Windows kernel binary is the same for all machines with this CPU
architecture (except the build options of PAE/noPAE and SMP/noSMP, I think
the latter is dropped from Win6 completely).

So, the Windows kernel binary cannot contain any code for particular
CPU-surrounding hardware like timers. HAL is the separate binary which
contains all this code - interrupt controllers (and the implementation of
IRQL), timers, hardware shutdown, interprocessor interrupts etc. Just look
at the list of HAL exports.

 

That requirement is more than just NT. Every version of Windows ever

IIRC some flavours of ARM, including the one used in iPaq devices, are
big-endian, and WinCE runs there for sure.

 

I believe ARM has both LE and BE modes.

 

Am I wrong that Platform Builder/eVC++ for ARM uses big-endian mode?

 

You are wrong. Windows CE requires that the ARM be set in little-endian
mode.

Originally, Windows NT was planned to have big-endian support. There was
even a processor enumeration for it. Those plans were quickly dropped.

 

IIRC, that was the Intel i860, the first CPU NT ran on. Back in the early
90s, I did firmware & software for an i860-based coprocessor board. I
implemented the firmware and most of a SVR4-based kernel before the project
was cancelled for lack of funds. The i860 was one of Intel's rare misses --
a RISC core surrounded by a floating-point unit reminiscent of Floating
Point Systems' vector processors for DEC VAX.

 

Yes. While double-checking this, I cam across a fascinating web site that
describes a part of this story I never knew:

http://www.winsupersite.com/reviews/winserver2k3_gold1.asp

When it became clear that the i860 was not going to ship, the NT team
switched to a MIPS R3000 chip, in big-endian mode. So, the very first
computer to run Windows NT was a big-endian system!

It wasn't until shortly after that that they moved to the i386, swallowed
the little-endian pill, and the rest is history.

 

When it became clear that the i860 was not going to ship

i860 was more-or-less widely used as a 3D graphics processor, the role now
played by GeForce and Radeon.

It was used this way in some high-end expansion boards for usual PCs, in
some Silicon Graphics machines and IIRC in NeXT.

It was never widely successful, being beaten by other RISC CPUs like Alpha
in speed, and then abandoned by Intel in favour or Pentium.