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Path: utzoo!watmath!clyde!cbosgd!ihnp4!houxm!houem!marty1
From: marty1@houem.UUCP (M.BRILLIANT)
Newsgroups: net.micro.trs-80
Subject: Again: What makes the Model 4 work?
Message-ID: <408@houem.UUCP>
Date: Mon, 11-Nov-85 17:02:18 EST
Article-I.D.: houem.408
Posted: Mon Nov 11 17:02:18 1985
Date-Received: Tue, 12-Nov-85 04:57:20 EST
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 26

As long as sob@neuro1.UUCP (Stan Barber) has replied on the net
to my question about how to access the special features of the
Model 4 when I only have a cassette system, let me continue:

Stan says "... you can push info out to certain ports to make
things happen.... but it is hard to use 64K of ram that is empty. 
Once you do the ROM swapout, there is no way to load the ram with
anything....  You cannot use the 4 in III mode with the 80x24
screen without a special driver to cause all the video mapping to
happen right....  Sorry this is such a downer."

OK, no problem!  I just want 80x24 for my terminal emulator.  It
has its own screen driver, it uses ports for RS-232, and I can
copy a keyboard driver.  The Model III screen and keyboard maps
are in the part of the address space that goes away in Model 4
mode, so I have to know what to do instead.  But I have the source
for the terminal program.  I can hack what I need, load it from
cassette in Model III mode, let it swap into Model 4 mode, and run!

So, I'm still asking Stan or anybody else: what info goes through
what ports to get into, use, and get back from Model 4 mode?

		M. B. Brilliant		houem!marty1
		39 McCampbell Road
		Holmdel, NJ 07733	(201)-946-8147
		AT&T-BL Holmdel, NJ	(201)-949-1858