Date: Tue, 22 Aug 1995 14:51:55 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, terry@cs.weber.edu Cc: freebsd-hackers@FreeBSD.org, msmith@atrad.adelaide.edu.au, roberto@keltia.frmug.fr.net Subject: Re: Install issues (was: State of the union speech Message-ID: <199508220451.OAA23697@godzilla.zeta.org.au>
next in thread | raw e-mail | index | archive | help
>I agree on the label's wanting to "go away". But I think that since >the disklabel is on a logical physical device, it's important; that's >because the disklabel is the critter that exports the terminal device that >is represented as a logical array of disk blocks and that's where the >file systems go. >This is exactly what he wants to do, it's just that a filesystem goes >on the logical physical device and gets mountes as well. There should be an ioctl to set the in-core slice table. This would be easy to implement. >> >The PowerPC under a PReP/OpenFirmware implementation assumes a DOS >> >partitioning scheme, but uses the sector offset field rather than the >> >C/H/S field -- 4GB worth of 512 byte sectors, or 2TB of disk. >... >This is actaully a very clean implementation. >The point I was making, though is that they assume this on *every* disk, >even floppies. If it has the signature, it has a partition table on >it, wierd as it may seem to have a floppy with a partition table. The So does FreeBSD :-). Oops, I never committed the changes for slices on the floppy driver because everyone would have to change their floppy device minor numbers to the standard scheme used for hard disks. Anyway, it's inconvenient to have sliced floppies. >In general, it's necessary to abstract the difference between terminal >devices, which are allowed to have file systems on them, top level >... >This approach has the advantage of working for the existing partition >and slice handling, the vnconfig device, AND the exportation of a >contiguous chunk of disk as a device AND extended partitions, all OTOH, uniformity requires the platform-dependent intermediate devices (slices) to be available on all real devices although the platform may only require them on some real devices. >without ruining the distintions in the kernel that cause some of the >current install problems (ie: WD1007). These problems are only indirectly related to slices. Given 4 different wrong ways of obtaining the geometry: 1) from the device 2) from the BIOS geometry in the boot info (this way is wrong mainly because we don't have a robust way of mapping BIOS drive numbers to device names) 3) from the DOS partition table 4) from the label, I decided to standardize on 1), but 1) doesn't work for the WD1007. Previously the driver used all of 1), 3) and 4) and finished up using 4). The geometries given by 1), 3) and 4) may all be different. This was confusing. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199508220451.OAA23697>