Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!elroy.jpl.nasa.gov!decwrl!public!thad
From: thad@public.BTR.COM (Thaddeus P. Floryan)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: ST157N
Message-ID: <1894@public.BTR.COM>
Date: 24 Feb 91 02:23:46 GMT
References: <#Y-#3D=@linac.fnal.gov>
Organization: BTR Public Access UNIX, MtnView CA, Contact: cs@btr.com 415-966-1429
Lines: 44

In article <#Y-#3D=@linac.fnal.gov> gad@linac.fnal.gov (Greg A. Deuerling) writes:
>	I've just got a used Seagate ST257N with no documentation.
                                     ^^^^^^
>Can any one out there tell me how to set up the SCSI ID on this.  I have
>a ST277N also,  but the jumper block is not the same on the ST157N.
>Any help at all will be much appreciated.

From Seagate's ST125N/ST138N/ST157N Product Manual, Rev. C, page 14:

	     50-pin SCSI conn.     Config
	:::::::::::::::::::::::::  :::::

Seagate documents the "Config" jumper block as:

	  2   4   6   8  10
	+-------------------+
	| O   O   O   O   O |
	| O   O   O   O   O |
	+-------------------+
	  1   3   5   7   9

	J1- 2: jumper IN, PARITY enabled; jumper OUT, no parity
	J3- 4: no connection
	J5- 6: SCSI ID bit 4; jumper IN, bit=1; jumper OUT, bit=0
	J7- 8: SCSI ID bit 2; jumper IN, bit=1; jumper OUT, bit=0
	J9-10: SCSI ID bit 1; jumper IN, bit=1; jumper OUT, bit=0

		4 2 1	SCSI ID
		- - -	-------
		0 0 0	  0
		0 0 1	  1
		 ...	 ...
		1 1 1	  7

HOWEVER, from my notes and my recollection of installing several ST157N drives,
and confirmed by Seagate itself, the three ID jumper positions are reversed
from what the docs show; thus:

	J5- 6: is really SCSI ID bit 1
	J7- 8: is really SCSI ID bit 2
	J9-10: is really SCSI ID bit 4


Thad Floryan [ thad@btr.com (OR) {decwrl, mips, fernwood}!btr!thad ]