Re: hdprefix - Load etherboot directly from a harddrive

Hi Marty,

Yes, Experimental tag would be probably be a good idea :-)

Like floppyprefix replaces the bootblock on the floppy, hdprefix just 
replaces the bootblock on one of the harddrives primary partitions, 
*not* the MBR.

It uses INT13 AH=02h; standard BIOS calls (CHS) for re-reading the MBR, 
1. sector of the disk (not a problem).
If your BIOS supports LBA (INT13 ah=42h), it will use LBA for the rest, 
otherwise it will stay with standard calls.

This means (I guess), that if your BIOS does not support LBA, the 
etherboot-image must be within the infamous 528MB limit. If your BIOS 
supports LBA, I read somewhere that the limit is about 137GB. I think it 
is the same method as GRUB is using!?!

Perhaps someone else here knows more regarding limits with standard and 
LBA BIOS calls?

~Per


Marty Connor wrote:
> On Jul 30, 2005, at 5:19 AM, Per Dalgas Jakobsen wrote:
> 
>> Hmm, perhaps I should hint that the patch has been uploaded ;-)
>> http://sourceforge.net/tracker/index.php? 
>> func=detail&aid=1247871&group_id=4233&atid=304233
>> ~Per
> 
> 
> Per,
> 
> Thank you very much for this patch.  It seems like quite useful  
> functionality.
> 
> Now normally I'd tend to want to put it in the development branch, but  
> since that branch is not yet ready for release, I think this should go  
> into 5.4.1, with perhaps an "Experimental" tag, to alert people that it  
> is new.
> 
> As I'm testing 5.4.1 I'll give it a try.  It looks like it just  
> replaces the boot blocks on an HD partition.
> 
> Are there any limitations we should be aware of (things like "Must be  
> within the first N GB of the disk" or "requires fairly modern BIOS") ?
> 
> All in all it looks quite useful, and the patch seems to be unlikely to  
> break anything else, so I'd be inclined to include it.
> 
> Can some other developers take a look and make any comments?
> 
> Thanks,
> 
> Marty


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