Re: [gentoo-user] ~amd64 compatibility with modern cpus

[Florian Philipp]

Am 14.12.2012 17:18, schrieb felix@×××××××.com:
> Something went haywire with my 8 or 9 year old dual Opteron ~amd64
> system last night.  I may have a bricked system.  I haven't given up
> yet, but I may have to buy a replacement system.  I have external USB
> drive backups, but the only other computer I have right now is an old
> Mac laptop which can't read Linux LVM partitions.
>
> Questions:
>
> 1.  I don't remember, and can't look up, the make.conf processor
> flags I emerge with.  But it is dual Opterons, and ~amd64.  How
> compatible could that be with modern Intel CPUs?  I know Intel
> adopted the extra registers of the AMD64 instruction set, but are
> there other differences which would prevent an Opteron system from
> running as is under an Intel processor?  Maybe AMD still sells
> Opterons, and I will be stuck with building a system.
>

I guess your Opterons used -march=k8. Except of 3dnow, this should be
compatible. You might be lucky.

> 2.  Is it feasible to buy some commodity box, like from Dell, with an
> Intel processor, and plug in my two SATA SSD drives and get a console
> boot?  I don't give a fig right now about any GUI interface, and even
> Internet is not the problem.  If it will boot and run emerges, I can
> import the source files for X and Ethernet and other peripherals via
> USB stick.  But SATA drivers ...
>

Yep, SATA drivers will be the biggest issue. Hope you had and will have
AHCI.

> 3.  My kernels always have just about every driver compiled in as
> modules, an old habit from when I used to swap in PCI cards like
> crazy.  I don't remember now how many SATA drivers are built in and
> how many are modules; if the commodity box needs SATA drivers which
> aren't built in, that could get tricky.  Are there boot command line
> options to preload certain modules?  Might not do me any good.  I
> think I could scrape by with USB modules, but not SATA.
>

Not possible. You need an initrd or a new kernel. How about compiling a
new kernel on a different box and using a memory stick for grub + /boot?

> For the curious, here is wat happened.  When I left off last night,
> the USB keyboard was only recognized when I unplugged all other USB
> devices, and the system hung at the grub point, with a blank screen.
>
> A reboot failed because it couldn't find the root=/dev/sde drive.
> But the USB keyboard was working because I used it in grub to select
> a new 3.7.0 kernel (had been running 3.6.8).
>
> A second reboot ignored the USB keyboard and generated an ATA error I
> had never seen before for every ATA drive and some I don't have, all
> the way up to ATA13 before I rebooted it again.  I haven't got it to
> boot even this far since, so I can't regenerate that error.  There
> was a 5 second or so delay between these errors, making me think the
> ATAnn designator might not be different drives, just retries.
> [...]

Could be your south bridge. If you want to keep the system, try a
different board.

Regards,
Florian Philipp