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

[Michael Mol]

(Admittedly quick and dirty response)

On Fri, Dec 14, 2012 at 11:18 AM,  <felix@×××××××.com> wrote:
> 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'm not aware of any currently-sold AMD or Intel x86 processors
(except, *maybe* Atom) which don't handily support x86_64. You should
have no problem here.

>
>     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 ...

Depends on if you have the necessary drivers installed, but yes, it's
a recoverable scenario. You might need to boot a live CD and compile
and install a kernel with the right drivers. It'd be like installing
Gentoo fresh, but skipping 95% of the handbook.

>
>     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.

NAFAIK. I'd just use the Gentoo live CD image.

>
> 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.
>
>     It booted a rescue DVD, but without the keyboard it was kind of pointless, and it hung after showing two lines which I believe are unrelated other than a place marker (generating xxx key, generating RSA key).
>
>     The keyboard wasn't even recognized by the BIOS.  I finally disconnected every USB device, all the ubs, and then the keyboard worked.
>
>     But when I left it last night, it wouldn't even bring up the grub screen.  All the BIOS screens show the usual disk drives.
>
> The system was working perfectly fine before all hell broke loose.  The keyboard was recognized during grub the first time, but after that only if all other USB devices were disconnected.  The disk drives acted funny during the boot, first with the unknown root- device error, then with the funky ATA errors, and finally with not even bringing up grub.
>
> I will try some more desperate tricks today, like reconnecting the USB pile to see if it at least boots the disks again - is my choice between disks and keyboard?  I will find out.  My best guess right now is that booting 3.7.0 is what clobbered things; whether I added a option which loaded bad firmware, or 3.7.0 is broken, I have no idea.  It could well be something unrelated to 3.7.0.  My goal for today is to try to get keyboard and disk working, then boot with 3.6.8.

Pull out an old PS2 keyboard. Sometimes, that's the easiest way to get
things going.

--
:wq