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Path: utzoo!mnetor!seismo!rutgers!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: mount vs. 3.5" drives
Message-ID: <2061@cbmvax.UUCP>
Date: Tue, 30-Jun-87 18:50:08 EDT
Article-I.D.: cbmvax.2061
Posted: Tue Jun 30 18:50:08 1987
Date-Received: Thu, 2-Jul-87 01:00:45 EDT
References: <384@esunix.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 23

in article <384@esunix.UUCP>, blgardne@esunix.UUCP (Blaine Gardner) says:
> Keywords: why
> 
> A question that has occured to me while trying to get an 80 track 5.25"
> drive to work on my Amiga: Why don't 3.5" drives have to be "mounted"?
> 
> What "magic" is there in the 3.5" drives that allows them to be
> automatically recognized by the system, that the 5.25" drives don't
> have?

Neither drive has to be mounted if it has an Amiga recognition circuit on
it, as do both the C-A 3-1/2" drive and the C-A 5-1/4" drive.  On startup,
the system polls drives DF1: and beyond for a string of 32 bits on the RDY
line.  An 80 track drive sends the string "FFFFFFFF", a 40 track drive sends 
the string "55555555", and if no drive is in that slot the "00000000" string
is returned.  If there's interest (when I've got a few more minutes), I'll
post how this can be done with simple hardware.

> Blaine Gardner @ Evans & Sutherland
-- 
Dave Haynie     Commodore-Amiga    Usenet: {ihnp4|caip|rutgers}!cbmvax!daveh
"The A2000 Guy"                    BIX   : hazy
	"Catch a wave and you're sittin' on top of the world" -Beach Boys