Dedicated disks from a sparc64/-CURRENT system into an Alpha

[Nick Jones]

I'm trying to install two IDE disks that were created in dedicated mode on a
Sun Ultra5 running -CURRENT (from about a month ago) into a Compaq
Professional Workstation XPS1000 running 5.1-RELEASE.  The disks are attached 
to a Promise ATA100 PCI IDE Controller, and both devices are detected on boot 
as follows:

ad0: 58644MB <IC35L060AVER07-0> [119150/16/63] at ata2-master UDMA100
ad1: 114473MB <WDC WD1200JB-00DUA0> [232581/16/63] at ata2-slave UDMA100

The corresponding entries in fstab taken from the sparc64 installation are:

/dev/ad1f               /data1          ufs     rw              2       2
/dev/ad0d               /data2          ufs     rw              2       2

However, neither 'ad0d' or 'ad1f' exist on the Alpha, and bsdlabel simply 
returns:

willow# bsdlabel /dev/ad0
bsdlabel: /dev/ad0: no valid label found

If I put the drives back into the sparc64 box all is well, so it's not
something that's happened physically to the drives during removal and
reinstallation.

Any ideas?  This is actually the first time I've really messed with 5.x and
devfs in particular so it might be something obvious I'm neglecting to do, but
I can't see it.

TIA.

-- 

/Nick