[Coco] CoCoRX

[John W. Linville]

I'm not sure that is a realistic failure scenario, but I guess it
could be possible...  Still, all you would get is a random crash and
only if the mysterious writer overwrote code that still gets executed
and even then it depends on what value gets written.

YMMV, but I would favor the methodical test with the program hosted
in ROM.

John

On Fri, May 29, 2015 at 12:14:48AM -0400, Dave Philipsen wrote:
> Mmmmm....it's impossible to overwrite ROM.  A program could run just fine in ROM while bad hardware is trying to overwrite the ROM but can't. The same program program fails miserably when you run it from RAM.  It's not always easy to find RAM errors because you have to write different bit patterns and even different contents into 'adjoining' cells but programs are generally unforgiving and have a nice variety of bit patterns in their opcodes.  A single bad bit of memory that holds a program will sometimes rear its head more quickly than a methodic test of the same memory.
> 
> Dave Philipsen
> 
> > On May 28, 2015, at 5:10 PM, John W. Linville <linville at tuxdriver.com> wrote:
> > 
> >> On Thu, May 28, 2015 at 04:25:14PM -0400, Dave Philipsen wrote:
> >> You could write the program in position independent code and offer on option for it to copy itself from cart ROM to internal RAM and run it from there....just an idea....or it could copy itself to RAM in the same position and then switch over to 64k mode....
> >> 
> >> I'm sure you could get enough people to contribute code to make it work.
> > 
> > What would be the purpose of doing that?  You would already need to
> > test the RAM before it makes sense to do that, and the ROM would have
> > to work for the program to run at all...?
> > 
> > John
> > -- 
> > John W. Linville        Someday the world will need a hero, and you
> > linville at tuxdriver.com            might be all we have.  Be ready.
> > 
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-- 
John W. Linville		Someday the world will need a hero, and you
linville at tuxdriver.com			might be all we have.  Be ready.