On 02/08/2012 10:04 PM, David Riley wrote:
On Feb 8, 2012, at 8:29 PM, Dave McGuire wrote:
Using a
SCSI controller is the way out but watch for dives over
1GB for the boot drive. I forget if that affected only the older
3100s or also the uVAX-II boot as well.
It's not an issue on the MicroVAX-II because it'll only end up
speaking MSCP to the controller, and never knows there's SCSI on
the other end. It's an issue for early integrated desktop
VAXstations because the boot ROM only uses so many bits (I forget
how many just now) to address a logical block.
I think it's actually a limitation of early SCSI commands; the 6-byte
READ command has an LBA of 21 bits (1GB if you're talking 512-byte
blocks). The 10-byte READ commands have 32-bit LBAs, which will
still only do 2TB (which ought to be enough for anyone, right?).
That's what I said...kudos for remembering the number of LBA bits,
which I forgot. This is handled in the boot ROM, though...once the
system is booted, larger-capacity drives aren't a problem.
-Dave
--
Dave McGuire
New Kensington, PA