Summary of sd0c not recognized by 4/330

From: Steve Lee (
Date: Wed Feb 07 1990 - 16:50:52 CST

Last week I asked help for the problem of an external disk sd0c not
recognized by 4/330 while the other external disk sd4c is seen. Here is
the summary.

1) The symptom 1 & 2(sd0 not seen at the boot time) is still there. The
system only goes out to search for that disk at the first attempt to use
that disk. I don't know if this is because sd0 has special meaning to
the system. Some said the SCSI controller in 4/330 can take only 4 SCSI
devices. Is it true? (I have 2 internal disks, a tape, and 2 external
disks on the same SCSI controller.)

2) Symptom 3 apparently was my mistake to use the raw device on the
mount command (most of the persons pointed out this also).

3) However, the entry in fstab was using the block device alright. But,
the system still hung at the boot time if /dev/sd0c and /dev/sd4c were
both in fstab. And if I removed the /dev/sd0c from fstab and boot the
system, then manually mount the file system, it occasionally hung. Even
it mounted ok, it would fail at the cp from sd4 to sd0.

4) Jack Wade from Z Microcomputers came out here and spent 3 hours with
me to find out the only possibility is the length of the SCSI cable.
Although the vendor of the disk said the SCSI controller could take up
to 18 feet of the cable, it might be unstable like in my case.
Yesterday, I replaced a 6 feet SCSI cable with a shorter one from Jack,
and tried a numerous test (copy, mount, reboot, ...), not a single fail.

Thank you to all who replied.

        Michael Maiten from Energetic Systems
        Rick Ord form UCSD
        Mark Plotnick
        Robert L. Krawitz from Thinking Machine Corp.
        Sven Ole Skrivervik from S-Data at Norway
        William Ang from MIT
        Stephen Carr from Icad, Inc.
        Fabrice Cuq from UCLA
        Robert Iskander from Sun Microsystems

Steve Lee

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