Re: Netra X1 - Fast Data Access MMU Miss

[Eduardo Horvath <eeh%NetBSD.org@localhost>]

On Tue, 8 Feb 2011, Maurizio Caloro wrote:

> Hello Martin
> equal, if i boot from Netbsd 5.1 Sparc64 CD-Rom or Harddisk i become this 
> message. Please you know this Error?

The "Fast Data Access MMU Miss" error is the PROM telling you that 
something attempted to access a memory location that was mapped into the 
PROM.  This happens before the MMU is taken over by the kernel.

We need to determine where the fault is occurring to be able to diagnose 
it.  Try adding the "-vV" flags to the boot command.  That should 
increase the verbosity of the boot process and give a better idea where 
things are failing.  Can you send us a log of the boot messages?

> 
> with meny reset-all or reset -x i have from 50 try possibilites to Boot one 
> time correct. 
> 
> with ideea i have damaged disk i buy a new one.

If the problem happens with both the disk and CDROM then the problem is 
unlikely to be fixed by replacing the disk.  

Now the old bootblock and ofwboot only understand ffsv1 and expect to find 
the filesystem superblock at an 8KB offset from the start of the 
disk/partition.  (The newer multi-format boot block also understands lfs 
and most of ffsv2, but I don't think that's made it to 5.1.)  

If the bootblock finds a superblock at the 8KB position but the rest of 
the filesystem has been overwritten, either by a different partition or a 
RAID volume, it will get confused and generate this error.  If you have 
nothing else on the disk you can try zero-ing out the first 64KB or better 
yet 128KB and then reinstall NetBSD on that disk and see if it fixes the 
poroblem.

Eduardo