Hi,

    If this is the same 9500 you have wrote about before and these devices are on
the mesh then it almost does not matter, since the mesh under NetBSD is NOT
synchronous capable at this time (unless that has been recently fixed). You are
not losing performance until you start talking about hanging non LVD devices on an
LVD bus. This will disable Fast-40 for all devices on an LVD bus. The only problem
you could bump into on the mesh is if you have a non-sync device on it and it is
using a large portion of the bus bandwidth that could be more efficiently used by
a faster device (3.3 MB per sec Vs 10 MB per sec).

                    kevin

P.S.:    Funny thing. In its current incantation (sync @ 6.25MHz on external and
async on internal), NetBSD on the 8500/8600/9500/9600 machines are actually faster
on the external bus, with appropriated devices.

Ben Harris wrote:

> In article <3C6DF98F.3020506@mac.com> you write:
> >2. I'm curious about the notations SCSI1 and SCSI2 on these
> >devices: Mac OS hides a lot of these details. The dribes at sd0
> >and sd1 are both internal, so it's not like they have different
> >connectors to clue me in. So are most of these devices SCSI2, ie
> >twice as fast as the original equipment IBM drive at sd0? Or is
> >this referring to something else?
>
> It refers to the command set that the device supports, which isn't directly
> related to what speed it works at, though of course devices using the newer
> command set will also tend to support faster transfers.
>
> > Am I losing performance by
> >having a SCSI2 device on that internal bus (though a circa 1995
> >machine is going to be SCSI1 on both buses, I assume).
>
> I'm not sure.  In NetBSD-current, SCSI drivers report what transfer rate
> they're using in a standard way, which makes it easier to see what's going
> on.  In any case, I'd expect the internal bus to be faster.
>
> --
> Ben Harris                                                   <bjh21@netbsd.org>
> Portmaster, NetBSD/arm26               <URL:http://www.netbsd.org/Ports/arm26/>