Installing an OS over the existing OS

[gene heskett]

On 2/18/23 04:43, gene heskett wrote:
> On 2/18/23 04:29, Phil wrote:
>>
>> On 16/2/23 15:50, Aaron Rainbolt wrote:
>>> On 2/15/23 23:44, Phil wrote:
>>
>> I decided to give option 3 a go. I removed the HDD and installed the 
>> OS onto the disk as an external USB drive connected to my working 
>> laptop. I wasn't sure if this would work and, after returning the HDD 
>> to the non-working laptop, I was surprised when it booted but with a 
>> grub rescue prompt and an unknown filesystem error.
>>
>> I'm not sure what I should enter but tried the following:
>>
>> set root=(hd0,6)
>>
> partition 6 is fairly likely to be too far into the disk for grub to 
> reach. I believe from past experience, that grub may have a limit as to 
> how many sectors it can reach into a disk. Something like 3.something 
> gigabytes into a big disk.  For that reason I have always put the boot 
> partition as the first working partition, after any efi stuff if 
> present.  Has that limitation been removed in grub > 2 ? IDK.
> 
Looks like it has been addressed, from pinfo grub:
Support Logical Block Address mode
      In traditional disk calls (called "CHS mode"), there is a geometry
      translation problem, that is, the BIOS cannot access over 1024
      cylinders, so the accessible space is limited to at least 508 MB
      and to at most 8GB. GRUB can't universally solve this problem, as
      there is no standard interface used in all machines.  However,
      several newer machines have the new interface, Logical Block
      Address ("LBA") mode.  GRUB automatically detects if LBA mode is
      available and uses it if available.  In LBA mode, GRUB can access
      the entire disk.

LBA has been available for quite some time now.  I'll get me coat.
>> set prefix=(hd0,6)/boot/grub
>>
>> I then restarted the laptop but was greeted with the same grub rescue 
>> prompt.
>>
>> Where to from here?
>>
> 
> Cheers, Gene Heskett.

Cheers, Gene Heskett.
-- 
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