Re: Big hard drives

[Ignatios Souvatzis <is%jocelyn.rhein.de@localhost>]

On Fri, Apr 09, 1999 at 12:41:00PM +0000, Patryk ?ogiewa wrote:
> Hi everyone.
> 
> Does anyone know the exact specifications of the (in)famous 4GB hard drive
> limit?
> 
> AFAIK it is the matter of the number of addressable blocks but what are the
> _exact_ limits? Drive size? Partitions size?

Several different.

For one, the classic IORequest interface can only reach the first
4*1024*1024*1024-1 bytes of the drive.

As a consequence, partitions containing Amiga bootblocks MUST BE COMPLETELY
WITHIN the first 4GB.

Other than that, NetBSD can address 4*1024*1024*1024* (fs fragment size) 
blocks using BSD FFS partitions.

I won't comment AmigaOS usage here. THere are 2.5 different approaches to make
AmigaOS work with >4GB drives.

> Why do I ask here? Since I've heard that NetBSD has no problems accessing the
> drives above the limits, I want to use All the HDD space that can be accessed
> from AmigaOS - for AmigaOS and all that is above the limits for NetBSD.
> 
> Could someone confirm or deny if I am right thinking this way? And give me
> clues about the exact limits or at least what exactly causes them so I could
> calculate them myself.

Uhm, you'll damage the disk if you use unmodified HDTOOLBOX with unmodified 
drivers on a big disk.

Other than that, your root partition must be below 4GB, so that the ROM can
access the bootblock, and the kernel on behalf of the bootblock.

        -is