Path: utzoo!mnetor!uunet!husc6!linus!necntc!ames!ucbcad!ucbvax!hoser.berkeley.edu!bryce
From: bryce@hoser.berkeley.edu (Bryce Nesbitt)
Newsgroups: comp.sys.amiga
Subject: Re: Serial port expansion
Message-ID: <22440@ucbvax.BERKELEY.EDU>
Date: 8 Jan 88 07:44:39 GMT
References: <197@imagine.PAWL.RPI.EDU> <4918@well.UUCP>
Sender: usenet@ucbvax.BERKELEY.EDU
Organization: The Logic Foundation
Lines: 41

In article <4918@well.UUCP> ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab) writes:
>	I project that this would slow down internal device transactions
>minimally...

Or not at all.  Recall that OpenDevice() fills in the io_Device field with
the device pointer.  After the open, calls would go directly to the 
proper device.  The only (tiny) assumption here is that a programmer
must not assume that all units of a device have the same io_Device.


>	I think this is a better approach as it avoids going behind Exec's
>back (it doesn't mess around with Exec's (probably private, don't-mess-with-
>these) lists).  Comments?

Leo is talking about the suggestion bart** made and I picked up that fools
the system in a controlled way.  Basically the first "serial.device" would
be linked AHEAD of the next in the device list.  When "OpenDevice"
chains down looking for the "serial.device" it finds yours first.
The old, dumb device is LAST in the chain.

	Let's keep this discussion going.  I'm not yet fully satisfied
	with any of the proposals as of yet.  Getting close, however.


** bart is the "Manager of Amiga ROM Software".  Messing with this should
not be a problem.  It was presented to me as either "approved" or
"approvable" by Commodore.


Please people!  Before you make the next comment on this, check out
the AutoConfig spec.  Also read the file called "drivers.doc".  You should
find it in the file "ReadMe1.2:Autodocs/autodocs.arc".  This is one
of the disks from the V1.2 Native Developer update kit.


>Leo L. Schwab

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