Subject: Re: UPDATE: Symbios 8750SP / IBM DDRS U2W boot problems
To: Jason Thorpe <firstname.lastname@example.org>
From: Joerg Czeranski <email@example.com>
Date: 05/17/1999 01:10:43
> On Mon, 17 May 1999 00:20:16 +0200 (MET DST)
> Joerg Czeranski <firstname.lastname@example.org> wrote:
> > > After adding "options SCSI_NCR_MAX_WIDE=0" to the kernel config file,
> > > it detects and uses the DDRS without problems:
> > rz0 at scsi0 target 0 lun 0 (LID=0) (IBM DDRS-34560D DC1B) (Wide16)
> So, you're saying that NetBSD negotiated Wide on the disk, then failed because
> it was connected via a narrow cable.
> ...yet Digital UNIX _also_ negotiated Wide, yet can use it even though it's
> connected via a narrow cable?
No, I'm not sure I'm saying that. :-)
I don't know whether the "Wide16" means that the disk could support wide,
or that it's switched to wide.
> A couple of comments...
> In order to make the disk work properly, I had to do some frobbing... First
> of all, I needed to set the "single-ended mode" jumper on the disk; I'm
> assuming you've already done that, since it talks to the host _at all_.
> Second, I needed to get a wide->narrow adapter that did the right thing
> with the unused signal lines; namely, pull them (and only them) to an
> active terminator. I think there's also a jumper that allows you to
> disable Wide negotiation.
The adapter had the unused lines open and the SRM console didn't recognize
the drive at all (though the same adapter worked with an UW DCAS and a
AXPpci33). I read an article in the German magazine c't about it,
they advised to connect the additional 8 data lines and a ninth line
together and via one 4.7kOhm resistor to the termpower line.
I did that, and only then was the DDRS detected by the SRM console
> Perhaps if you do the latter, the disk will (perperly) refuse to negotiate
> Wide transfers. In my case, obviously, the driver never tried.
> Now, it could be that Digital UNIX, when it detected a failed transfer
> in Wide mode, suppressed the error message, and fell back on Narrow.
> I don't know. And Digital UNIX drivers are pretty awful reading :-)
Maybe, I've never seen Digital UNIX sources. ;-)
Unfortunately the DDRS documentation doesn't mention a jumper for wide.
Only for single ended and target initiated synchronous negotiation (which
is off) and other stuff like autostart.
The host adapter came without printed documentation - I haven't checked
the contents of the windows floppy - and it doesn't have any jumpers
> Just out of curiosity, is ths a Tekram DC-390 board?
No, the stuff on the board reads:
"SYM8750SP", "FCC ID: B8JSYM8750SP",
"SYMBIOS LOGIC (c) 1996", "ASSEMBLED IN USA",
A sticker: "348-0036086A"
On the chip: "SYMBIOS LOGIC 53C985J 609-0392654 DP16007 9804N"
And I bought it as "original Symbios 8750".