Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!rutgers!sri-unix!hplabs!tektronix!tekcrl!vice!tekfdi!videovax!stever
From: stever@videovax.Tek.COM (Steven E. Rice, P.E.)
Newsgroups: comp.sys.amiga
Subject: Re: Daisy-chaining drives?
Message-ID: <4086@videovax.Tek.COM>
Date: Fri, 5-Dec-86 12:30:54 EST
Article-I.D.: videovax.4086
Posted: Fri Dec  5 12:30:54 1986
Date-Received: Sun, 7-Dec-86 23:56:02 EST
References: <812@ulowell.UUCP>
Reply-To: stever@videovax.Tek.COM (Steven E. Rice, P.E.)
Organization: Tektronix Television Systems, Beaverton, Oregon
Lines: 35
Summary: The documentation says you need external power.

In article <812@ulowell.UUCP>, Peter G. Trei (OC.TREI@CU20B.COLUMBIA.EDU)
writes:

> . . .  At the end, when we were packing up,
> we tried daisy-chaining a second external drive onto one of the
> machines.
> 
> We ran into problems: Workbench showed df2: as 'BAD'. c:info
> showed df2: as 'unreadable'. c:list put up a requestor with 'Non-Dos
> disk in df2:' c:format ran ok during the format stage, but verify
> failed. (We did not try reading that disk in another drive). We could
> not write to the disk in df2:.
> 
> Some people suggested that the power supply was not up to it; but
> I am under the impression the it is supposed to be able to run up to 3
> externals. Anyone have any idea what we did wrong?

When I was setting up my Amiga system, I read the documentation for the
pieces.  It is my recollection (I don't have the documentation in front
of me) that all the pins on the external disk unit are passed through,
*except* power (pin 9???).  (The select lines are barrel-shifted so the
first disk in the chain is df1:, the second df2:, and the third df3:,
but this is not important here.)

The reason given for *not* passing power through is to avoid overloading
the internal power supply.  If you want to use more than one external
drive, it will be necessary to get a box that provides the power to
each of the additional drives.  (I believe I saw a product of that sort
advertised in the Amiga Hardware Review that came a couple of months
after I sent in my registration cards.)

					Steve Rice

----------------------------------------------------------------------------
{decvax | hplabs | ihnp4 | uw-beaver}!tektronix!videovax!stever