James Olson wrote: > 2.4 kernel dmesg log: > hde: 6835952 sectors (3500 MB), CHS=6781/16/63, UDMA(33) > hdf: 6346368 sectors (3249 MB) w/96KiB Cache, CHS=6296/16/63, DMA > hdg: host protected area => 1 > hdg: 6346368 sectors (3249 MB) w/256KiB Cache, CHS=6296/16/63, UDMA(33) Too bad it doesn't tell you how large the HPA is, otherwise you could subtract that from the total size and look for metadata at the resulting sector... > Here is the 2.6 log: > hde: FUJITSU MPA3035ATU, ATA DISK drive > hdf: IBM-DAQA-33240, ATA DISK drive > hdg: WDC AC23200L, ATA DISK drive > hde: 6835952 sectors (3500 MB), CHS=6781/16/63, UDMA(33) > hdf: 6346368 sectors (3249 MB) w/96KiB Cache, CHS=6296/16/63, DMA > hdg: 6346368 sectors (3249 MB) w/256KiB Cache, CHS=6296/16/63, UDMA(33) I've seen 2.6 versions that do tell about HPA areas, I find it suspect that yours doesn't. Perhaps it's a bug (but it really does disable the HPA), perhaps there really is no HPA or perhaps the information has been intentionally removed from newer 2.6 kernels. Could you compare the number of sectors that Linux tells you above to the number reported by your BIOS? Just to get you up to speed on HPA: There was some discussion on linux-kernel, and the powers that be (Alan Cox) does not want to change the kernel's current faulty behaviour of automatically disabling the HPA, since that would break things for the few people that has partitions which span the HPA if they upgrade the kernel and do not manually enable the "HPA disable" thing. Most of those people supposedly have BIOSs where they can disable HPA the proper way (the ThinkPad users do, at least), but that argument didn't seem to stick. The only way forward right now that would pass the Cox barrier is a patch that change all the partition detection code to: * Know about HPA/non-HPA size of physical devices. * Detect partitions that are out-of-bounds of the non-HPA size. * Call IDE code to disable HPA when such partitions are found. Or patches that: * Change all user code to be aware of HPA versus non-HPA IDE disks. Both seems overly complex solutions compared to: * Fixing the kernel to behave itself and not disable HPA. * Provide a kernel command line flag or configuration option for those who need to disable HPA manually because they have a horrible BIOS. But that's how things are right now. > Also there is some question of the drive geometry between the different kernels. > The hdparm -g outputs differ. Maybe 2.4 does not disable HPA? 2.6 does (my best guess is that it does so because some IDE developer had a laptop which didn't allow him to disable HPA). Seems odd though, since the two logs you've given indicate that both kernels see the same number of sectors. What sector count do you get if you run fdisk on the two kernels? Blah blah. Sorry for the lengthy mail. _______________________________________________ Ataraid-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/ataraid-list
