[Coco] Copy Protection
Steve Ostrom
smostrom7 at comcast.net
Wed Jun 30 18:44:28 EDT 2010
----- Original Message -----
From: "Robert Gault" <robert.gault at att.net>
To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
Sent: Monday, June 28, 2010 10:19 PM
Subject: Re: [Coco] Copy Protection
> The code for *.BAS is essentially the same code found on any of the Tandy
> OS-9 system or games disks. It permits Disk Basic 1.0 to run the
> equivalent of the Disk Basic 1.1 command DOS.
> In the case of these game disks, *.BAS is loading some ml code from the
> disk to memory at $2600. If the bytes at $2600-$2601 are OS, then the code
> at $2602 is run.
> Since regA is loaded with $22, it is track34 which is being loaded into
> memory. That means if you have Disk Basic 1.1, you can start the programs
> by entering DOS instead of RUN"*".
>
> --
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> Coco at maltedmedia.com
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>
Robert, so if I just typed "DOS" the program will load and run the same way?
Geez, now I feel really dumb. That means the copy protection was removed
somehow prior to the disk being made. I still wonder what was used, and how
the directory was changed to show center adjusted text followed by the real
directory. That was a sweet touch! I'll use CDM to examine the directory
track in more detail.
Thanks!
-- Steve --
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