bill@camco.Celestial.COM (Bill Campbell) (01/27/91)
I would like to be able to use an external SCSI tape drive on several systems, but think there may be a problem with termination resistors. The problem is that there are both internal and external devices. As I understand it the internal hard drive and external tape should be terminated and the terminators should be removed from the host adapter. +-----------------+ +-------------+ +--------------+ | HARD DISK |___| 1542 |___| TAPE DRIVE | | (terminated) | | Untermin. | | (Terminated) | +-----------------+ +-------------+ +--------------+ Can I get away with removing the terminator from the tape drive so that there are only two terminators in the system? I don't whan to have to take the system apart to R&R terminators from the 1542 every time I need to use the tape. Thanks Bill -- -- INTERNET: bill@Celestial.COM Bill Campbell; Celestial Software UUCP: ...!thebes!camco!bill 6641 East Mercer Way uunet!camco!bill Mercer Island, WA 98040; (206) 947-5591
david@talgras.UUCP (David Hoopes) (01/30/91)
In article <708@camco.Celestial.COM> bill@camco.Celestial.COM (Bill Campbell) writes: > [stuff deleted] > >Can I get away with removing the terminator from the tape drive >so that there are only two terminators in the system? I don't >whan to have to take the system apart to R&R terminators from the >1542 every time I need to use the tape. > The terminators must be at the end of the chains. You might be able to buy and external scsi terminator and plug it in when the tape drive was removed. Warning. Don't go plugging and unplugging these cables while the system is powwered on. -- --------------------------------------------------------------------- David Hoopes Tallgras Technologies Inc. uunet!talgras!david 11100 W 82nd St. Voice: (913) 492-6002 x323 Lenexa, Ks 66214
gouwv1@idca.tds.PHILIPS.nl (J. van der Gouw) (01/30/91)
In article <708@camco.Celestial.COM> bill@camco.Celestial.COM (Bill Campbell) writes: **** stuff deleted ***** >As I understand it the internal hard drive and external tape >should be terminated and the terminators should be removed from >the host adapter. > > +-----------------+ +-------------+ +--------------+ > | HARD DISK |___| 1542 |___| TAPE DRIVE | > | (terminated) | | Untermin. | | (Terminated) | > +-----------------+ +-------------+ +--------------+ > >Can I get away with removing the terminator from the tape drive >so that there are only two terminators in the system? I don't >whan to have to take the system apart to R&R terminators from the >1542 every time I need to use the tape. **** stuff deleted ***** No you can't get away with removing the terminators on the external tape drive. According to the SCSI spec you must have terminators on both ends of the SCSI chain. However there are terminator blocks available (at least here in Europe) which you can connect to the external connnector of the AHA-1542. In that case you only need to take the system apart once and remove the internal terminators. Jos. ============================================================================= Jos van der Gouw Tel. : 31-55-432353 Philips Information Systems FAX : 31-55-432103 Apeldoorn The Netherlands. =============================================================================
kusumoto@chsun1.uchicago.edu (Bob Kusumoto) (01/31/91)
I'm not sure about having a tape drive and hard drive on the same SCSI
bus (well, it works on my sparcstation but not on my novell server) but
we got one external SCSI terminator which seems that you can plug into
a SCSI port and allows you to plug another port on top of it so that if
it's being chained through, it's not terminated but if it isn't, it's
terminating.
(ie: card<=====>SCSI_device<> terminated.
^ terminator
card<=====>SCSI_device<><====>SCSI_device[]
^ terminators ^
^ terminated here.)
It's kinda hard to explain if you don't look at it. Think of it as some
kind of serial adapter except it's for terminating SCSI buses. This way,
you can disconnect the 2nd device without fear not having the SCSI bus
being broken (although you're software or computer might disagree :-).
Cool idea if you ask me though.
Bob
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