(off topic) surprising results with unterminated tape drives

[Jim Bryant]

what percentage of backups were failing?  Failure on fresh or resaonably fresh tape should be next to nil.

the drive still needs terminated, noise can sometimes be low...or high...transients aren't called transients for nuttin.

after someone recently kicked loose the negative battery connection to my icom ic-706 mk2 in my car, i found that it will transmit 
on hf at 100 watts output with only a positive battery connection.  is this healthy?  no.  do you want to run with only a positive 
connection?  no.

just because it works, don't mean it ain't broke.

James E. Leinweber wrote:

> short version
> --------------------
> Can the combination of active negation by SCSI-fast devices plus
> SCSI-3 controllers backing down from unsustainably high transfer
> speeds tend to hide termination problems?
> 
> long version
> --------------------
> I recently discovered, to my shock and horror, that a small cabal of
> student-age hardware techies at our shop had been putting tape drives
> into high end PC systems without bothering to terminate them.  A
> typical scenario which I just fixed this afternoon would be:
> 
>   Adaptec 29160U2W SCSI card <-50 pin cable->Quantum DLT 4000 tape
> 
> They were blithely ignoring boot time warnings about undertermination
> on the grounds that the tape backups "were working OK".
> 
> I'm unpersuaded; _all_ of said systems have a history of mysterious
> failures of nightly tape backups, with much pointless troubleshooting
> of everything - drives, cables, and PCI slots - except the missing
> terminators :-)
> 
> But, they were getting a surprising high percentage of backups which
> where the data on tape apparently do compare favorably with the
> original data on disk.  Being a software guy who originally met up
> with SCSI in the SCSI-1 Centronics connector days, when lack of
> termination was a certain kiss of death, I'm a bit puzzled as to how
> they got away with it.


jim

-- 
          ET has one helluva sense of humor!
     He's always anal-probing right-wing schizos!
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