🚀 go-pugleaf

matthews@rainbow.rmii.com (Don Matthews) wrote:
>Joerg Erdei (a8101gbb@vm.univie.ac.at) wrote:
>: ralphs@tesser.com (Ralph Shnelvar) wrote:
>: >My guess is that your drive is supplying termination -power- (not just
>: >termination resistance) and by powering down the device you are
>: >causing a power fluctuation.
>: >
>: Nearby all todays SCSI devices provide termination power to the bus,
>: at least all of mine do. This should not do any harm to the bus, as
>: long as it is done according to the SCSI specification. I wonder	if
>: that is a more common problem, for till now I've never heard of this.
>
>: Joerg Erdei
>
>I think both you and Ralph are on the right track.  I'll bet all the problems
>described in this thread could be traced to the *source* of terminator power.
>It is true that most devices supply power.  And, in fact, the SCSI-2 spec
>states that it is mandatory for initiators to supply it and optional for
>targets to supply it.  Yet, responsible target manufacturers do it anyway.
>
>But what happens in the field is this ... all suppliers of terminator power
>have a fuse, and this fuse can easily be blown, especially if hot-plugging
>is involved (so I've heard, although it's never happened to me).  But the
>fuse can blow even if you're not hot-plugging.  It could turn out that in
>each of the problematic systems, term power was only being supplied by the
>device that is later being powered down, and that could explain why the bus
>doesn't then function.
>
>Best Regards,
>Don Matthews
>
If it is that way, the easiest solution is to get SCSI Sentry II from APS.
It is not only an excelent active terminator, it also provides termination
power through a seperat power supply, so it does not matter wich drive is
does or does not provide termination power.

Joerg Erdei

I am not related to APS in any way. I am just a satisfied user of their	
terminators and cables.