[Coco] Cryptic BASIC program

[Arthur Flexser]

Officially, Tandy took the position that in order to use 64K, you needed to
use OS-9.  64K was not supported under Basic.  However, there were ways to
take advantage of the presence of 64K without OS-9.  One was to copy the
ROMs to RAM, and use that either to modify the ROM code or to use unused
areas of the space in high memory not taken up by ROM code for other
things.  Telewriter-64 and some other word processors switched out the ROMs
(as OS-9 does) and used the space for storing text.  There were some third
party programs that enabled 64K memory to be used for Basic programming.
One was KEY264K, which allowed you to switch between 32K banks which both
contained Basic programs.

Art

On Sun, Sep 27, 2015 at 6:55 PM, Salvador Garcia <
ssalvadorgarcia at netscape.net> wrote:

>
>
> Since I am  master of misunderstanding this is entirely possible.  Then
> this program was only useful once to verify that the computer was set to
> 64K. I did not have to run it every time I started the CoCo.
>
> How were the 64K used? Or better said, how was the Ram used? Since part of
> the address space went to the ROM(s) what happened to the RAM that was
> addressed in the same space os the ROM(s)?
>
> Thanks, Salvador
>
>
>
> -----Original Message-----
> From: Arthur Flexser <flexser at fiu.edu>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Sun, Sep 27, 2015 2:04 pm
> Subject: Re: [Coco] Cryptic BASIC program
>
>
> 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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> > list
> > Coco at maltedmedia.com
> >
> https://pairlist5.pair.net/mailman/listinfo/coco
> >
> >
> >
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