Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!dlyons
From: dlyons@Apple.COM (David A. Lyons)
Newsgroups: comp.sys.apple2
Subject: Re: Unidisk 3.5" boot from a ][+
Message-ID: <43427@apple.Apple.COM>
Date: 29 Jul 90 21:55:55 GMT
References: <1990Jul28.065320.8921@xrtll.uucp>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 30

In article <1990Jul28.065320.8921@xrtll.uucp> frankl@xrtll.uucp (Frank Lemire) writes:
>I have a (real) Apple Unidisk 3.5, and I also have the unidisk controller 
>card. now my problem is, that no matter where I put my two drive controller
>cards (I have two 5.25s) my ][+ ALWAYS boots from the 5.25.
> 
>I've fixed this for the time being just by formatting the 5.25" with a
>DOS 3.3 disk and just having the hello program boot slot #5 (my 3.5)
> 
>Can anyone suggest what I could do to fix this problem and have my ][+ 
>boot the 3.5 first?

Your solution sounds pretty reasonable already.  Short of re-burining
your II+ monitor ROM, I don't have a better answer.

There is a reason machines before the enhanced IIe don't automatically
boot from SmartPort devices--I don't remember the details right now, but
it's in a ProDOS 8 Technical Note or Apple II Miscellaneous TN somewhere.

I believe it had to do with Apple II UCSD Pascal getting confused, thinking
anything that looked just like a bootable 5.25 controller card must
actually *be* one, so one of the ID bytes on the UniDisk card is different.
ROMs in the enhanced IIe and later no longer check that last ID byte.
-- 
David A. Lyons, Apple Computer, Inc.      |   DAL Systems
Apple II Developer Technical Support      |   P.O. Box 875
America Online: Dave Lyons                |   Cupertino, CA 95015-0875
GEnie: D.LYONS2 or DAVE.LYONS         CompuServe: 72177,3233
Internet/BITNET:  dlyons@apple.com    UUCP:  ...!ames!apple!dlyons
   
My opinions are my own, not Apple's.