FreeBSD 7.x hang-on-boot on Dell 1950

[Zaphod Beeblebrox]

I have a dell 1950 here on the floor.  Since "1950" seems to refer to a lot
of things with a lot of configurations, I'm going to attempt to narrow that
down a bit.

It's got 2x 2.33Ghz dual core pentiums (stepping 06-0F-6 according to the
bios) in it and it has an SAS RAID card that FreeBSD recognises.  I've
upgraded the BIOS to 2.6.1.  It has two SAS 70G drives in a RAID 1
configuration and it has a DVD (although it will only boot from CDs).

If it helps, it's between 2 and 3 years old, I think.

If I allow the machine to boot normally, it stopps after checking the floppy
(there is no floppy) with the following message:

fdc0: <floppy drive controller> port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on acpi0
fdc0: does not respond
device_attach: fdc0 attach returned 6

If I boot the machine without ACPI, it seems to stop at the same place
(stopping after having checked the ata controller, which checks right before
the floppy)

If I boot the machine verbose, I get no more information --- it stopps at
the same place.

I have tried this (so far) with 7.2-R and 7.1-R.  Both do the same thing.