what to do when grub lapic trick does not work?

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28 Oct 2014 15:52 #52483 by ArcEye

There is also one section that says that CPU is not identified and that no microcode is downloaded.


I am surprised at that, from what I read the C7 is basically an old Celeron chip
The kernel is built with microcode as a module, including Intel, AMD and generic old interface, maybe it needs to be built in for your CPU to be recognised?
It does not seem compatible with your hardware.

Anyway I would forget the Wheezy based distro and try installing the Ubuntu 10.04 based one.
I know it supports some non standard CPUs like Vortex and whilst it is SMP it is not a PAE kernel.

If that does not work, there is still the Ubuntu 8.04 based distro which does not require LAPIC. It also is a uni-processor build and will be better suited to your CPU.

As far as I recall the requirement for LAPIC support in the kernel is a RTAI thing. The older version of RTAI with 8.04 did not require it.

But now even if you build a UP kernel, as I did for my P4 workshop machines, you have to enable LAPIC in the kernel config or the later RTAI will not work

regards
The following user(s) said Thank You: MrkiMedo

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28 Oct 2014 18:10 #52488 by MrkiMedo

I am surprised at that, from what I read the C7 is basically an old Celeron chip


Oh no, C7 is somewhat similar to celeron in capabilities (or lack of them), but under the hood is completely different beast. C3, Eden (the one other poster had), and C7 are early attempts of VIA to enter the i86 compatible processor market. They acquired Nextgen company that had clean room prototype or early product of processor that could execute i86 instructions, and VIA had necessary licences for the bus so they could sell it. It would definitely not be able to use microcode from Celeron since internal architecture is different.

The kernel is built with microcode as a module, including Intel, AMD and generic old interface, maybe it needs to be built in for your CPU to be recognised?
It does not seem compatible with your hardware.

Anyway I would forget the Wheezy based distro and try installing the Ubuntu 10.04 based one.
I know it supports some non standard CPUs like Vortex and whilst it is SMP it is not a PAE kernel.

If that does not work, there is still the Ubuntu 8.04 based distro which does not require LAPIC. It also is a uni-processor build and will be better suited to your CPU.

As far as I recall the requirement for LAPIC support in the kernel is a RTAI thing. The older version of RTAI with 8.04 did not require it.

But now even if you build a UP kernel, as I did for my P4 workshop machines, you have to enable LAPIC in the kernel config or the later RTAI will not work

regards


I think I will pass this computer to be the browsing machine in the cottage house, and I will buy some bigger boxed PC with parallel port and Intel PIII or P IV processor. They seem to run for $20 in local classifieds and hopefully after one or two, I will find one that installs on the first run.

Thank you!

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28 Oct 2014 18:29 #52490 by ArcEye
Probably a good idea.

Don't get a PIII, the performance will be poor, a 2.4-2.8GHz P4 is quite good with 1GB RAM
If it has integral video chip, you may need an AGP card to take the video overhead off the system
(I use Matrox cards that cost about £5 each from ebay)

wiki.linuxcnc.org/cgi-bin/wiki.pl?Latency-Test gives some starters

Just be also aware if going for an older machine, it too will probably run much better on 8.04 than 10.04, because it is uni-processor.
Only some of the very late P4s were dual core.

regards

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