SPARCClassic won't boot cdrom

Michael Thompson michael.99.thompson at
Sun Aug 2 13:53:22 CDT 2015

> From: Benjamin Huntsman <BHuntsman at>
> Subject: SPARCClassic won't boot cdrom
> Hi all!
>    I recently acquired a SPARCclassic, which is my first bit of Sun
> hardware.  Having an awful time getting it to boot from the CD-ROM.  I have
> tried a bunch of different terminators and several different cables, but
> whenever I try to boot I get this:
> ok boot cdrom -s
> Boot device: /iommu/sbus/espdma at 4,8400000/esp at 4,8800000/sd at 6,0:d  File
> and args: -s
> The SCSI bus is hung.  Perhaps an external device is turned off.
>    Any ideas as to what might be wrong here?  The thing does not seem to
> send any commands to the CD-ROM, as the LED never comes on and I don't hear
> it doing anything...
> Thanks!
> -Ben

The terminator on the end of the SCSI bus needs to be powered. Without
power on the terminator the bus will hang. Sometimes the power comes from
the SPARC through the SCSI cable, but not all SCSI cables pass the power.
Sometimes there is a jumper or switch on the last drive to enable SCSI
terminator power.

Michael Thompson

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