Re: i386 boot1.c peculiarity while studying code

[Antoine LECA <antoine.leca.1%gmail.com@localhost>]

On 2015-01-08 22:47Z, David Laight wrote:
> On Wed, Jan 07, 2015 at 02:39:11PM -0500, William D. Jones wrote:
>> However, boot1.c proper calls a wrapper function for open ob() three times: 
>> line 80, 90, and 106. [...]
> 
> It should check for a disklabel and look for the offset of the root fs.
> However sysinst might have a non-obvious restriction that the root fs
> has to be at the start of the partition.
> If there isn't a valid label it assumes the root fs is at the start
> of ths mbr partition.
> 
> There is a hack for raidframe where it look for a valid filesystem
> 64 sectors further down the disk.
> I don't remember a 2nd fallback.

The first try is for a potential filesystem at the start of the "slice"
(MBR partition if you prefer) from which the boot1 code was loaded.
As David recorded correctly, the 2nd try is to deal with raidframe metadata.
The third try is for the 'a' partition as located by the disk label.

The comments seem pretty clear to explain all this.


Antoine