Hi,
On Fri, Feb 22, 2013 at 3:36 AM, escape <esc...@front.ru> wrote:
> On 22.02.13 03:22, Rugxulo wrote:
>
>> If you just want 64-bit support *and* DOS support (but not necessarily
>> in the same program, which would be hard, if not "almost" impossible),
>> your best bet would be DOSEMU (x64) or VirtualBox with latest (Nehalem
>> Westmere-ish) hardware cpu VT-X support enabled.
>
> Just curious. Current 64-bit mode was developed by AMD, and later
> adopted by Intel for use in their own processors.
I'm no engineer, so take it with a grain of salt. But 2003 was when
the first 64-bit AMD Opteron servers appeared while Intel didn't add
support to their Xeon servers until 2004. It wasn't until 2006 (Core
2?) that all Intel and AMD home machines supported 64-bit. (EDIT:
Wait, some late-model Pentium 4s also had it [nocona?].) Even VIA's
latest and others like latest Intel Atom support AMD64 nowadays.
> All current AMD
> processors, except cheapest Semprons, even E-series intended for
> netbooks, support AMD-V virtualization, which was introduced a little
> later, than Intel VT-x, but turns out to be more effective and simpler
> to implement in software. In the same time, not all Intel processors
> support VT-x, which Intel uses to segment its market.
>From what I've heard, yes. AMD has similar but incompatible
virtualization. I don't remember the abbreviations that Linux's
/proc/cpuinfo uses (svm?). AMD was "Pacifica" and Intel was something
else. (EDIT: Wikipedia says "Vanderpool" and "vmx".)
Yes, AMD supports "paged real mode" while only with Nehalem Westmere
did Intel support similar ("unrestricted guest mode execution", "real
mode and big real mode", or whatever). This is in addition to other
weird changes (EPT). IIRC, Win8's Hyper-V (64-bit only?) requires EPT,
but Win7's XP Mode does (no longer) require any VT-X at all.
> Support for VT-x
> may even vary between different versions (as identified by Intel's sSpec
> Number) of the same model number. To differentiate between them, while
> making a decision, you must refer to a complete list on the Intel
> website. Not to mention, that in addition to AMD-V, all current AMD
> processors support ECC RAM.
Yes, it's confusing. IIRC, things like Core i3 don't have VT-X, but
again, it may vary depending on model.
In fairness, as long as we still have traditional BIOS support, it's
probably "easier and faster and most compatible" to just reboot
entirely to "real" DOS, as I know DOS386 is waiting to scream at us!
;-)
> Nevertheless for "64-bit support *and* DOS support" Intel is a "best bet"?
No idea, kinda doubt it, but anyways .... The PS4 was just announced
two days ago, and apparently it will be a special AMD 8-core x86-64
with AMD GPU and 8 GB of RAM. I can't say I blame them, it's fairly
popular and ubiquitous, probably easier than messing with the Cell
cpu(s).
BTW, things in the worldwide market are going to get further messy
when ARM actually starts producing (if not already) their 64-bit
architecture, support for which has already been added to a few GNU
tools.
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