Re: For comment: draft BIOS use document for the kernel

H. Peter Anvin
2001-06-22T19:05:44Z

Followup to: <Pine.LNX.3.95.1010622135228.3929C-100000@chaos.analogic.com>
By author: "Richard B. Johnson" <root@chaos.analogic.com>
In newsgroup: linux.dev.kernel
>
> On Fri, 22 Jun 2001, Alan Cox wrote:
>
> > > I could not find any reference to BIOS int 0x15, function 0x87, block-
> > > move, used to copy the kernel to above the 1 megabyte real-mode
> > > boundary. I think this is still used.
> >
> > I dont think the kernel has ever used it. The path has always been to enter
> > 32bit mode then relocate/uncompress the kernel, then run it
> >
>
> Then how does 1.44 megabytes of data from a floppy disk (that won't
> fit below 1 megabyte), that is accessed in real-mode, ever get to
> above 1 megabyte where it can be decompressed?
>
> I think LILO copies each buffer read from a below 1 Megabyte buffer
> (which is the only place the floppy can put its data via the BIOS),
> to above 1 megabyte using the BIOS block-move function.
>

This is done by LILO, which isn't part of the kernel. SYSLINUX, for
example, enters protected mode directly (like the kernel itself does).

-hpa
--
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