Newsgroups: comp.periphs.scsi
Path: utzoo!utgpu!cunews!bnrgate!bwdls61!bwdls56!fortinp
From: fortinp@bwdls56.bnr.ca (Pierre Fortin)
Subject: Re: ACB-4000A help!?!?!?
Message-ID: <1991Apr16.081800.10409@bwdls61.bnr.ca>
Sender: usenet@bwdls61.bnr.ca (Use Net)
Organization: Bell-Northern Research, Ottawa, Canada
References: <41277@cup.portal.com>
Date: Tue, 16 Apr 1991 08:18:00 GMT

In article <41277@cup.portal.com>, ekalenda@cup.portal.com (Edward John Kalenda) writes:
> I have an AST 4000 disk/tape unit for which I have no docs. The disk
> works as SCSI unit 0 but I would like to have it be unit 1. If
> anybody out there has docs on the ACB-4000A, I'd appreciate help with
> the following questions. Before you say to call Adaptec, I've already
> done so without ever getting to talk to anybody but the receptionist
> and several voice mail machines.
> 
> Can the card support a second drive?

Yes.  I have two 4000A controllers online with 2 drives on the first and 1 
drive on the second.  You need to daisy-chain the 34-pin connector to both
drives, and a separate 20-pin cable from J1 to drive 1.

> How does the card know the disk parameters (heads, cylinders, etc.)?

This is a drive issue, not a controller issue in this case.

> What is the function of the jumper block that looks like this?
> 
> 	O M K I G E C A
> 	: : : : : : : : J5
> 	P N L J H F D B
                      ^ LSB of controller address
                    ^
                  ^     MSB of controller address
                ^       DMA transfer rate (max rate with no jumper)
              ^         extended command set (when replacing SASI controllers)
            ^           not used
          ^             install jumper to support drives that drop SEEK
                        COMPLETE line on the ST506/412 interface during
                        head switches.
        ^               jumper enables self-diagnostics


> 
> How about the jumper near J1:
> 
> 		R
> 	    PU     S
> 		T

These jumpers are used to select the write pre-comp for the two connected
drives.  It overrides MODE SELECT software selections.  Pre-comp is 12ns.
R-PU:  no pre-comp
R-S:   pre-comp starts at same cylinder as reduced write current (both drives)
R-T:   pre-comp all tracks (both drives)

> 
> How do I remove the onboard termination? I presume it is the resistor
> packs labelled RP4 and RP3 since they are socketed.

If this is the only controller, do not remove these terminators; otherwise, 
remove them on all but the last controller on the SCSI chain (except if using
an external terminator; in this case remove all controller terminators).

> 
> The disk is a Fujitsu M2243AS. Anybody know what the switch pack and
> four jumper blocks do?

Nope... sorry.

> 
> Always searching for more disk space at minimal cost,
> Ed
> ekalenda@cup.portal.com


Cheers,                      
Pierre Fortin       fortinp@bnr.ca         (613)763-2598