[OpenBIOS] OpenBIOS: reality check
Aaron M. Gowatch
aarong at wired.com
Sun Mar 1 11:36:48 CET 1998
On Sun, 1 Mar 1998, David Woodhouse wrote:
> Not so. At least on the SX164 we have, it knows about the filesystem. Anyway,
> the phrase "the location of which is described by values stored on the first
> 512 byte sector" sounds suspiciously like understanding disk partitions to me.
Ahh... the Windows NT AlphaBIOS that runs on the PC164. Its a lot like
the Windows NT ARC firmware, but it is not SRM.
What does reading raw sectors off of a disk have to do with partitions?
Before any disk has partitions or even filesystems on it, it has sectors.
Do you think the MBR is a partition? You store these values in the first
512 byte sector of raw disk and you read them.
> The SRM firmware understands at least FAT, and possibly also NTFS partitions.
> Certainly it's capable of loading second-stage bootloaders like "LINLOAD.EXE"
> from a FAT floppy disk. I believe that even the emergency firmware update is
> managed from a FAT floppy.
Again, the Windows NT AlphaBIOS, tailored specifically for running Windows
NT, has support for these filesystems. It is not SRM. I dont see the
point in developing such OS specific BIOS extensions.
> Making new filesystems just so that the BIOS can access them easily is not
> practicable. Neither is the idea of dedicating a partition to BIOS extensions.
> Simple read-only filesystem support can be kept fairly small, and is going to
> be required by UNIX people to load either the second-stage bootloader or the
> kernel itself.
Agreed, creating new filesystems is probably not practical. But saying
that a filesystem is required in order to boot UNIX is entirely false.
The concept of reading sectors directly from disk independent of
partitions or filesystem is not a new one. I'd suggest that you read the
SRM Firmware HOWTO:
OpenBIOS -- http://www.linkscape.net/openbios/
openbios-request at linkscape.net Body: un/subscribe
Problems? dcinege at psychosis.com
More information about the openbios