[Coco] Cryptic BASIC program

[Arthur Flexser]

You probably misunderstood the Radio Shack guy, who likely was telling you
that running the program would verify that the machine indeed had 64K.  (It
actually checks only that one aspect of installing a 64K upgrade, moving a
jumper, was done, not that the RAMs are good.)   Or else the Shack guy
himself was confused, which would not be unusual, even back then.
(Nowadays, you can just assume they know nothing about computers.)

Art

On Sun, Sep 27, 2015 at 2:45 PM, Salvador Garcia <
ssalvadorgarcia at netscape.net> wrote:

>
> Thanks all for your feedback and explanation of the code.
>
> Although I understood all that was explained, I am not sure exactly what
> effect this small program has when I run it. I remember the Radio Shack guy
> telling me that I had to run it in order for the CoCo I to recognize all
> 64K; however, given the 1600/16000 discrepancy, I am not sure what the code
> as given actually does. I need to get more stuff done, but if I have time I
> will unpack the CoCo I and try out both versions of the code to see if I
> can detect any difference.
>
> Again, thanks, I appreciate your time in effort in helping me out.
>
> Salvador
>
>
>
> -----Original Message-----
> From: Arthur Flexser <flexser at fiu.edu>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Sat, Sep 26, 2015 10:56 pm
> Subject: Re: [Coco] Cryptic BASIC program
>
>
> On Fri, Sep 25, 2015 at 11:18 PM, Darren A <mechacoco at gmail.com> wrote:
>
> >
> > It
> is not a good substitute for a real RAM test program. It merely checks
> > the
> jumper setting which Basic uses at initialization time to decide how to
> >
> configure the SAM chip.  I'm not sure if the CoCo will even boot correctly
> >
> when the SAM is configured for the wrong type of RAM chip.
> >
>
> I recall you could
> fool a 32/64K CoCo 1 into setting the SAM for 4K by
> pressing the reset button
> with shift and break held down, so
> apparently CoCo Basic will tolerate a wrongly
> set SAM configuration in at
> least some cases.
>
> (This was the basis of the
> shift-break-reset method of breaking out of a
> copy-protected program, allowing
> certain special methods of removing the
> copy protection to be employed.  Not
> usable with Color Basic 1.2 (?) and
> above due to the elimination of checking for
> the 4K possibility in later
> versions of Basic's warm start routine.  After
> shift-break-reset, most
> commands give an out-of memory error in the 4K
> configuration, but CLOADM
> and EXEC work, so you can regain control of the
> machine and switch back to
> 64K SAM mode.)
>
> Art
>
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