Path: utzoo!attcan!uunet!decwrl!elroy.jpl.nasa.gov!usc!apple!blob
From: blob@Apple.COM (Brian Bechtel)
Newsgroups: comp.sys.mac.hardware
Subject: Re: IIfx SCSI termination question
Message-ID: <42859@apple.Apple.COM>
Date: 11 Jul 90 14:19:13 GMT
References: <2155@esquire.UUCP>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 29

baumgart@esquire.dpw.com (Steve Baumgarten) writes:

>I know people keep asking this with alarming regularity, but does
>anyone know the correct way to terminate the SCSI chain in a IIfx:

>	1. With only an internal drive.
>	2. With both an internal drive and an external tape drive.

>Apple is woefully negligent in this area; although the IIfx comes with
>"Technical Info" and "Setting up Your IIfx" manuals, neither of them
>address the question.  

I disagree.  Appendix A of "Setting up Your IIfx" contains complete
instructions on termination.  

If you have an internal drive from Apple, it's already terminated.
Don't add any additional termination.  If the drive is by some other
company, contact that company for termination information.  You do need
special termination; see Technical Note 273 for much more detail.

The basics of SCSI termination are:
 * One terminator at the beginning of the chain
 * One terminator at the end of the chain
 * No terminators anywhere else.
With that in mind, put the black terminator that came with the IIfx on
the last device in the SCSI chain.  You can put the terminator either
in-line with the last cable, or on the adjacent connector.

--Brian Bechtel		blob@apple.com		"My opinions, not Apple's"