[X4U] Very weird disk corruption - pleas for help!

[Stroller]

On 26 Mar 2008, at 05:36, Jim Robertson wrote:
> ...
> Any ideas what I should try next?

This has got to depend on whether you need any data that's on the drive.

If so, then I would try booting the laptop in firewire target mode &  
trying to see if you can see the partitions from another machine.

If not, then why haven't you tried the original MacBook Pro system  
disk? I don't know whether I can start the computer from it, either,  
but it's got to be worth a try.

It seems to me there are two possibilities:
- you've got disk corruption that is confusing the MacOS boot-manager.
- you've got an unrelated hardware problem - maybe the motherboard is  
hosed. Maybe this caused your initial booting problems, or maybe it's  
just completely unrelated. This might seem unlikely, but it does happen.

If you had a 2.5" SATA hard-drive lying around it would be easy to  
prove or disprove the latter scenario. If you can install MacOS on a  
brand new hard-drive using this machine then you know the problem is  
corruption on the original drive, but if you can't install MacOS on a  
new drive then it'd appear to be some other hardware problem. If it  
DOES turn out to be the latter case then you'll be glad you've  
diagnosed this early, as doing so would save you a lot of time.

The former case - disk corruption that is confusing the MacOS boot- 
manager - is in principle easy to solve, assuming you don't care  
about your data. All you need to do is to erase the partition table &  
job's a good 'un. Having said that, "easy" depends upon the tools  
available to you. I would pull the laptop's hard-drive (mind you,  
this is easier on my plastic MacBook than it is on a MacBookPro),  
plug it into some other machine and use `dd if=/dev/zero of=/dev/ 
$drive` - the operation can be cancelled within seconds with Ctrl-C  
because the partition table is zapped in moments, and when the drive  
is replaced in the machine it will be recognised as unformatted and  
without partitions.

If you're able to to be apathetic about the data on the drive then  
another way to remove the partition-table would be to boot with a  
Linux CD. I would imagine Ubuntu might well support Intel Macs these  
days and as long as you're able to boot to that (I would doubt that  
it would be bothered about existing partitions the  way one of  
Apple's CDs might be) then you can do the dd thing I described above.  
I assume your DiskWarrior disk doesn't have any tools for erasing the  
drive.

I hope I've been helpful - if you need the data of the laptop (I  
wouldn't, because I don't keep anything important on my laptop) then  
I wish you'd've told us & saved me typing out these suggestions.

Finally, PLEASE DO NOT CROSS-POST TO MULTIPLE MAC MAILING LISTS. This  
is not usenet!! When you post a question to a mailing-list you're  
asking readers to help you. But when you cross-post, readers do not  
have the benefit of seeing all the other replies (those made to the  
other list), so they could be wasting their time repeating  
suggestions that have already been made (or made & dismissed) on the  
other list. In future, please choose only ONE mailing list to post  
to, and only follow-up to the other (with a summary of what's been  
done, tried & suggested already) if you don't get your problem solved  
within a few days.

Stroller.