PartitionMagic question

[Iavor Raytchev]

I am installing FreeBSD on a laptop with Windows XP Pro. I created empty 
space with PartitionMagic and installed FreeBSD there making the FreeBSD 
partition with the FreeBSD partition utility in the install.

I took the drive geometry from PartitionMagic as the BIOS does not tell 
it (ThinkPad X30). The installation went well and both OS boot well.

When I run PartitionMagic it reported 3 errors - different LBA and CHS 
values - the errors are on the first sector of the FreeBSD partitions 
and on the first sectors of the next two partitions (seeing from the 
LBA). PartitionMagic says in all 3 cases that the LBA and CHS values are 
different. In all 3 cases the CHS value is the same - 15483887 (drive 
geometry is 5168/240/63). After PartitionMagic repairs the errors 
everything is OK. Both OS boot well.

My questions are -

a) does somebody know why the errors appear?

b) is the installation safe after the errors are fixed?

PartitionMagic is listed officially as installation preparation utility 
and I assume it should be safe to use it afterwards, apart from touching 
the FreeBSD partition.