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From: ags@pucc-i (Seaman)
Newsgroups: net.micro.apple
Subject: Re: hires_question
Message-ID: <394@pucc-i>
Date: Tue, 14-Aug-84 11:23:28 EDT
Article-I.D.: pucc-i.394
Posted: Tue Aug 14 11:23:28 1984
Date-Received: Thu, 16-Aug-84 01:18:31 EDT
References: <494@bunker.UUCP>
Organization: Purdue University Computing Center
Lines: 20

The "double-density" hi-res mode is a hardware feature of the Apple //e.
No modification is required.  All you need is the Apple extended 80-column 
board (the one with 64K on-board memory, for a total of 128K).  Double 
density probably also works with the Apple //c, but I can't say for sure.  
It definitely does not work with the II+, and there is no simple hardware 
modification that will make it work.

One exception:  If you have a //e with a "Revision A" motherboard (manufactured
within the first month or so after the //e was released) you may need a
hardware modification, which your Apple dealer will handle for free.  You
must have the Extended 80-column board in order to get the modification.

The only software I have heard of which makes use of double-denity hi-res
graphics is Apple Pascal 1.2.  The Apple //e Reference Manual and the
Extended 80-column Card User Manual describe how double-density mode works
(i.e. what soft switches to set, and how the memory is mapped).
-- 

Dave Seaman			My hovercraft is no longer full of 
..!pur-ee!pucc-i:ags		eels (thanks to my confused cat).