>On Tue, Aug 03, 1999 at 02:44:47PM -0800, Grant Stockly wrote:
>>
>> What do you mean?  If I were to make a file system image to load into RAM
>> from ROM (like the install disk) then it woudldn't need disk info, or would
>> it?
>>
>> Doesn't NetBSD use the info it gets when it scans the IDE busses?
>
>Here's how things work (I think :):
>-  the boot loader computes a checksum of the first sector(s) of each disk
>   the bios knows about. It passes this to the kernel, along with the
>   bios # of the boot disk.
>- when looking for the boot device (once all disks have been probed, just
>  before starting init) the kernel computes the checksum of the first
>sector(s)
>  of each disk it knows. This way it can map back its disks (wd0, wd1, sd0
>...)
>  back to the bios disks # (what is conventionally called C:, D:, E:, F:).
>
>It needs to do this mapping back in order to find the boot device, because
>all what the boot loader can tell it is that he booted from X: (where
>X can be any of C,D,E,F).
>On my system at home, depending on bios config C: will be wd0 or sd0.
>
>Now, if you boot a kernel with en emmbeded ramdisk you don't need this:
>just put:
>options         MEMORY_DISK_HOOKS
>options         MEMORY_DISK_IS_ROOT     # force root on memory disk
>in your kernel config file, as well as:
>pseudo-device   md    1

But I want to have a hard drive connected to this device (for mass temp
storage).  Could I disable the BIOS checksum thing?

Grant