[Coco] Coco Digest, Vol 55, Issue 35

[carl j england]

> Message: 1
> Date: Sun, 20 Jan 2008 10:10:49 -0600
> From: Roger Taylor <operator at coco3.com>
> Subject: Re: [Coco] Recovering Fast Cassette Saves
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Message-ID: <20080120161053.7BFB57D114 at qs281.pair.com>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
> 
> You can save and load tapes in 2mhz mode if the device would allow 
> for it.  I used to use a Sony MD Walkman (minidisc recorder) and it 
> 
> worked fine.  I've never seen a tape deck able to do this.  Maybe 
> it's the audio tapes themselves, but I remember using a VCR in SP 
> mode a Long time ago and it worked.
> 
> 
> 
> 
> 
> At 08:28 AM 1/20/2008, you wrote:
> >Rogelio Perea wrote:
> >
> >>Was browsing the December 1985 issue of The Rainbow and came 
> across a 'hint'
> >>from a Ryan Devlin (Louisville KY). According to his note, the 
> following
> >>string of commands would allow a Basic program to be loaded back 
> into the
> >>CoCo *after* the program had been saved to tape with the CoCo in 
> high-speed
> >>mode:
> >>POKE 143,8:POKE 149,24:POKE 145,4:CLOAD
> >>The days when I relied with cassettes to do my CoCoing are long 
> gone, but
> >>during those times I did save a couple of programs forgetting to 
> kick back
> >>the CoCo into its normal speed. I took those files as 'lost' 
> saves, trying
> >>to retrieve the file keeping the CoCo sped up proved unreliable.
> >>Just curious at what the line above does. Is it altering a timing 
> loop?.
> >>
> >>-=[ Rogelio ]=-
> >
> >Those are the bytes that contain the 1200/2400Hz partition time, 
> >upper limit of 1200Hz, and upper limit of 2400Hz.
> >
> >Seems to me it would be much easier to just read the tapes in Fast 
> 
> >mode, but maybe that doesn't work.
> >
> >--
> >Coco mailing list
> >Coco at maltedmedia.com
> >http://five.pairlist.net/mailman/listinfo/coco
> 
> 
> 
> 
the high-speed poke for the coco1&2 (65495) only altered the speed of the
coco when it was accessing the code in ROM.  since the write to cassette
and read from cassette used different code (and a different ratio of ROM
to RAM) the write and read speeds did not match.  you could save and load
at the "real" high speed poke (65497), but the coco1&2 lost the screen
display and it wasn't really useful.  the coco3 "normally" ran in the all
RAM mode and the GIME chip allowed the screen to display using the "real"
high speed poke, so there was no problem saving and loading files at
double speed.  (i did experiment with saving and loading at high speed on
my coco1 and had no problems other than having to type POKE65496,0
blindly after the cassette motor stopped)

but that is why it is so difficult to load a file that has been
accidently saved at high speed.