Messages in this thread | | | Date | Sat, 13 Sep 2003 20:05:33 +1400 | From | Matt Domsch <> | Subject | Re: 2.7 block ramblings (was Re: DMA for ide-scsi?) |
| |
On Sun, Sep 14, 2003 at 05:26:54PM -0500, Alan Cox wrote: > On Sad, 2003-09-13 at 17:11, Matt Domsch wrote: > > system-unique disk signature to the boot disk (int13 device 80h) > > "BOOT" or something - we've got 4 bytes available in the msdos label > > for it > > int 13 is still available during the 16bit boot up phase of the kernel. > It does strike me as playing with fire, but an alternative approach > might work. Read the first 4K off the boot disk, stuff it somewhere > temporary and then in 32bit compare it with the disk starts..
This is essentially what we are proposing, only instead of reading 4K, read 1 sector and stash the 4-byte disk signature where we can get at it later, and export it via edd.o for comparison later. This much is easy, as the empty_zero_page has 512 bytes free for reading the sector in setup.S, and 4 bytes we can use to stash the signature until setup.c runs where we can copy it somewhere safe. Then export it via edd.o through /proc (2.4) or /sys (2.6).
The thing that writes the signature to disk can be anything that can issue int13 calls. Right now we do it in a FreeDOS app, but a special loadlin/syslinux/isolinux used for OS installation may be simpler and not require a FreeDOS environment be run ever.
-Matt
-- Matt Domsch Sr. Software Engineer, Lead Engineer Dell Linux Solutions www.dell.com/linux Linux on Dell mailing lists @ http://lists.us.dell.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |