Just nailed my BIOS & Vista partition

[Jim Cornette]

Hadders wrote:
> Tim wrote:
>> On Sun, 2006-12-17 at 11:29 +0900, Hadders wrote:
>>  
>>> Okay, so Grub clearly upset Vista by "switching"/"hiding" things.
>>>     
>>
>> The hide option modifies the partition tables on the drive - changing
>> the partition *type* from one that the system might read, to a hidden
>> type.  Perhaps your other OS didn't like the type?
>>
>> I'm not sure of the value of hiding a partition.  It shouldn't be
>> necessary for booting from another drive.  You should just be able to
>> select the drive to boot from.  If you find some things insist that they
>> must be on drive 0 when they're on drive 1, there's the map option to
>> pretend they're plugged in the other way around.
>>
>> map (hd0) (hd1)
>> map (hd1) (hd0)
>>
>> (If I recall correctly...  Consult the grub info file to be sure.)
>>
>>
>>   
> wicked! that's fixed the Vista problem too.
> A quick scan of the device with fdisk showed that it has a "hidden NTFS 
> partition", changing it back to "7" HPFS/NTFS and voila, I'm back in 
> business, now I understand what Grub did.
> Thanks heaps!
> 
> Now, the question is what does the map command do? just a memory swap? 
> or something actual?
> 
> Thanks
> 

There are hexadecimal codes which drive 0 and drive 1 use for drive 
recognition through BIOS. The command does what it says and switches the 
identity so the OS sees hd0 as hd1 and hd1 as hd0.

Someone might have a more technical explanation.
Jim

-- 
Computers can figure out all kinds of problems, except the things in
the world that just don't add up.