AIC7902 SCSI aborted command

[Wilko Bulte]

On Mon, Aug 04, 2003 at 04:10:15PM -0400, Don Bowman wrote:
> From: Justin T. Gibbs [mailto:gibbs at scsiguy.com]
> > > After ~200 hours of operation a PC spit out this message:
> > > 
> > > Copied 18 bytes of sense data offset 12: 0xf0 0x0 0xb 0x0 
> > 0x0 0x40 0xff 0xa
> > > 0x0 0x0 0x0 0x0 0x47 0x3 0x8 0x0 0x0 0x0
> > > (da0:ahd0:0:0:0): WRITE(06). CDB: a 0 40 ff 80 0
> > > (da0:ahd0:0:0:0): ABORTED COMMAND info:40ff asc:47,3
> > > (da0:ahd0:0:0:0): Reserved ASC/ASCQ pair field replaceable unit: 8
> > > 
> > > The system has a single U320 15KRPM seagate 18GB drive in it.
> > > No other messages are present.
> > 
> > This means that the target saw a CRC miscompare on a packet.  CAM
> > retried the command and it succeeded.  CRC errors are not unheard
> > of in U320 configurations, but at only 200 hours of load, that is
> > a little too often for comfort.
> > 
> > I believe you mentioned before that you were using an extremely
> > short cable in one of your configurations.  Be aware that there
> > is a minimum cable length suggested by the SCSI spec.  This
> > varies depending on the capacitance rating of your cable, but
> > the shortest length allowed is 10cm (cables with less capacitance
> > need larger spacing).  If your cable is shorter than this, you might
> > consider trying something longer.
> 
> Me & my trusty ruler re-measured the cable, and straightened out,
> it is 10.4" tip to tail, which matches the spec. I was foolishly
> thinking of the folded length.

It isn't too folded I hope? In the sense that you sometimes
find flatcables stashed in miniscule cutouts in cases etc. Not
too good for signal integrity either.

-- 
Wilko