Re: ZoomFloppy - formatting a disk in a 2031 disk drive

From: Spiro Trikaliotis <ml-cbmhackers_at_trikaliotis.net>
Date: Sat, 26 May 2018 11:23:59 +0200
Message-ID: <20180526092359.5rd72djdgiuplata@hermes.local.trikaliotis.net>
Hello,

* On Sat, May 12, 2018 at 06:43:14PM +0200 Mia Magnusson wrote:
> Den Fri, 11 May 2018 14:55:02 +0200 skrev And Fachat <afachat@gmx.de>:
> > Am 11. Mai 2018 14:36:55 schrieb Mia Magnusson <mia@plea.se>:
[...]
> > > Are there any people around who has made the german magazine 64er
> > > modification for a 1541 to become a 2031lp?
> > 
> > Yes in fact I have made it. Never had any problems. But the 64er
> > modified the ROMs such that they only changed the 1541 IEC routines
> > to IEEE, but not all of the ROMs. So it is more of a modified 1541.
> 
> Interesting. I had thought that the ROMs were more or less the same.

They are.

But as the higher ROM is changed, the entry points into the routines
change, too. Thus, $C000-$DFFF also differes whenever an entry point to
routines in $E000-$FFFF is referenced.

The 64er magazine made sure that the routines stayed at the same place
they have in a 1540/1541, so there was no need to modify the $C000-$DFFF
ROM.

Regards,
Spiro.

-- 
Spiro R. Trikaliotis
http://www.trikaliotis.net/
Received on 2018-05-26 12:00:07

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