SUMMARY: Disconnected command timeouts

From: Ahmon Dancy (
Date: Fri Jul 07 1995 - 06:31:12 CDT

I received many responses to my problem of Disconnected command timeouts.

WARNING: /iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000 (esp0):
Disconnected command timeout for Target 3.0

Target 3 is an HP-C1533A tape drive.

Most of the responses recommended checking SCSI cables and terminators but
(except for the internal drives and cables) I had done so prior to posting
the help request. We're using high quality cables and terminators. I can
vouch that replacing low quality cables high better cables can solve many
SCSI problems. Unfortunately it didn't solve mine.

My best help came from:
misawa@physics.Berkeley.EDU (Shigeki Misawa) (Bevis King)

With their help I came to the following solutions/conclusions:

I checked the tape drive owner's manual and checked to see what the maximum
transfer rate was. The manual indicated 7.5Mbps/sec (Async). I ran
'scsiinfo' on the host machine and it indicated that the transfer rate was
negotiated to be 10Mbps/sec. Shigeki suggested that I call HP and make sure
I had the lastest firmware revision of the drive (On the same note, the
man page for the esp driver alos says that disconnected command timeout message
indicates a firmware problem on the target). Unfortunately I do have the
latest firmware revision but the guy at HP suggested that I call their BBS
and download the "Dithy Python" patch which makes the tape drive act like
a Python tape drive (which, apparently, Solaris 2.4 is more familiar with).
I haven't done this yet because of what I'll discuss below.

Before calling HP I had tried a few other things. I checked out
/kernel/drv/st.conf (the scsi tape device configuration file). I read over
the man page a few times and found a way to increase the timeout time for
the device. So far this has worked for me so I am satisfied. However,
if it fails again, I will resort to the Python patch.

Other ideas:
Play with /kernel/drv/esp.conf to disable disconnected commands.
Play with /kernel/drv/esp.conf to adjust the maximum transfer rate for
 the target.


Thanks for your help, everyone!

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