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From: dzimmerman@gnh-tff.cts.com (Daniel Zimmerman)
Newsgroups: comp.sys.apple2
Subject: Re: Would you believe?
Message-ID: <1991Jun22.103639.6381@crash.cts.com>
Date: 22 Jun 91 10:36:39 GMT
Sender: root@crash.cts.com
Organization: Crash TimeSharing, El Cajon, CA
Lines: 36

jeffb@world.std.com (Jeffrey T Berntsen) writes:
> mattd@Apple.COM (Matt Deatherage) writes:
> 
> >All ROM space is reserved for Apple and may not be used by third-party
> >developers for any reason.
> 
> Huh?  I thought Apple had published specifications for using part of this
> space as a ROM disk.  Am I imagining things?
> 
> -----------------------------------------------------------------------------
> Jeffrey T. Berntsen                 | Looking for a good .sig
> jeffb@world.std.com                 |
> -----------------------------------------------------------------------------

I seem to remember that Apple reserved certain parts of the ROM addresses, but
left the rest open... From the "Technical Introduction To The Apple IIGS", by
Addison-Wesley - Page 18, "In addition to expansion RAM, the memory expansion
cards can also have up to a megabyte of ROM. The additional ROM occupies
memory from bank $FD downward to bank $F0. Portions of the top two banks of
expansion ROM are allocated for system firmware expansion. The remaining
expansion ROM is supported as a ROM disk - permanent storage for applications,
which the system handles like disk files..."

I don't know if that has changed since the ROM 3 came out (and used those 2
top banks to double the ROM size, I believe, but I could very well be wrong),
but at least in 1986, when the "Technical Introduction" was written, ROMdisks
were supported by Apple..

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