Subject: Re: partition bookkeeping
To: Oleg Polyanski <firstname.lastname@example.org>
From: Bill Studenmund <email@example.com>
Date: 09/23/1999 12:33:17
On 23 Sep 1999, Oleg Polyanski wrote:
> >>>>> "IS" == Ignatios Souvatzis writes:
> IS> Maybe I should add that for normal booting, root devices tend to not
> IS> change their name all the time, so having the sysadmin edit fstab once
> IS> at installation or reconfiguration time is good enough.
> >> Consider my disk has name `sd0' (because it was detected first during
> >> the kernel booting). Later I will add ZIP drive and IT will get the name
> >> `sd0' and hard disk will become `sd1'. Bad surprise, manual intervention
> >> required. Something like `/dev/scsi/dsk/c0d0p0' as root fs unique
> >> identifier will help.
> IS> If you insist to make your boot drive scsi id 1, and not having any
> IS> fixed disk scsi id 0, you can still wire down the sd unit of your root
> IS> disk in your kernel configuration.
> OK, here are excerpts from my `dmesg' output:
> NetBSD 1.4K (TINDERBOX) #1: Sat Sep 18 15:08:22 MSD 1999
> cpu0: family 6 model 5 step 1
> cpu0: Intel Pentium II (Deschutes) (686-class)
> pciide0 at pci0 dev 7 function 1: Intel 82371AB IDE controller (PIIX4)
> pciide0: bus-master DMA support present
> pciide0: primary channel wired to compatibility mode
> atapibus0 at pciide0 channel 0
> sd0 at atapibus0 drive 1: <IOMEGA ZIP 100 ATAPI, , 23.D> type 0 direct removable
> sd0: drive offline
> sd0: 32-bits data port
> pciide0: primary channel interrupting at irq 14
> sd0(pciide0:0:1): using PIO mode 3
> pciide0: secondary channel wired to compatibility mode
> atapibus1 at pciide0 channel 1
> ncr0 at pci0 dev 16 function 0: ncr 53c875 fast20 wide scsi
> ncr0: interrupting at irq 10
> ncr0: minsync=12, maxsync=137, maxoffs=16, 128 dwords burst, large dma fifo
> ncr0: single-ended, open drain IRQ driver, using on-chip SRAM
> ncr0: restart (scsi reset).
> scsibus0 at ncr0: 16 targets, 8 luns per target
> sd1 at scsibus0 targ 1 lun 0: <SEAGATE, ST52160N, 0285> SCSI2 0/direct fixed
> sd1(ncr0:1:0): 20.0 MB/s (50 ns, offset 15)
> sd1: 2069 MB, 6536 cyl, 4 head, 162 sec, 512 bytes/sect x 4238282 sectors
> sd2 at scsibus0 targ 2 lun 0: <SEAGATE, ST36530N, 1206> SCSI2 0/direct fixed
> sd2(ncr0:2:0): 20.0 MB/s (50 ns, offset 15)
> sd2: 6208 MB, 9006 cyl, 6 head, 235 sec, 512 bytes/sect x 12715920 sectors
> So, what you mean when you say `you can still wire down the sd unit
> of your root disk in your kernel configuration'?
What we mean is that if you add
sd0 at scsibus0 targ 1 lun 0
to your kernel config and rebuild, then sd0 will ALWAYS be drive 1 on scsi
bus 0. You should probably also add
ncr0 at pci0 dev 16 function 0
scsibus0 at ncr0
So that you're certain that sd0 is always target 1 on the scsi bus off of
the ncr scsi adapter in that particular PCI slot.
You could then add scsi controllers in any other slot, add 3 other zip
drives (2 ide busses w/ 2 targets each), and sd0 won't move around.
If you change scsi controllers, or move that scsi bus to a different
controller, sd0 will no longer show up. If you leave sd* at scsibus?
target ? lun ? in the file, then the drive will show up at some other sd
That's what we mean about wiring devices down. You can get the same effect
of cXtYlZpQ if you want, but you also get something much more flexabile.