[Coco] Recovering a damaged cassette file

Thu Sep 6 10:03:09 EDT 2012

Well, one thing to watch out for is that, before the end-of-program
pointer is correctly set, any typo will trash the program by causing
an attempt to create a variable name from your typo that is stored
near the beginning of the program, overwriting the data.  So maybe
that accounts for your lack of success with the pokes.  Look at what
is stored at the address contained in $19-1A and see if it looks like
a tokenized program.

Art

On Thu, Sep 6, 2012 at 9:28 AM, Bill Pierce <ooogalapasooo at aol.com> wrote:
>
> Art, I tried the pokes below, poking in a high address in all the spots. No listing.
> Is there a flag or something that needs to be set telling basic that a program loaded successfully?
> It's been a long time since dealing with tapes, and I had cheap recorders so I had to save many tapes :-)
> I just don't remember the whole proccess, but it seems like there was something else you had to set to let basic know there was a program in memory and if it errors, this was reset.
> I not be 'memberin' things since the pockyclips.....
>
> Music from the Tandy/Radio Shack Color Computer 2 & 3
> https://sites.google.com/site/dabarnstudio/
> Bill Pierce
> ooogalapasooo at aol.com
>
>
>
>
> -----Original Message-----
> From: Arthur Flexser <flexser at fiu.edu>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Sent: Thu, Sep 6, 2012 3:33 am
> Subject: Re: [Coco] Recovering a damaged cassette file
>
>
> If the file is tokenized Basic, it shouldn't be too difficult to
> reconstruct it up to the point where the error occurs.  The format of
> each line is this:
> address of the start of the following line (2 bytes); the line number
> (2 bytes); the tokenized version of the Basic statement; zero
> terminator.  Addresses $19-1A contain the address of the program
> start, typically $2601 on a disk system or $1E01 on a cassette system
> if the default PCLEAR 4 is in effect.  ($2600 or $1E00, the byte
> before the program start, should contain a zero byte) $1B-1C contains
> the address of the program's end (one byte after the final zero
> terminator, if I'm remembering right).  The address of the end will of
> course be messed up if the program has only partially loaded;  just
> poke in some address past the end of what managed to load in.  You
> should also poke the same value into $1D-1E, $1F-20, and $21-22 so the
> variable and array storage areas come right after the end of the
> program.  (Addresses are from memory;  somebody should double check
> that this is right.)   You should then be able to list and save what's
> been loaded, if the line pointers are intact.  If the program lists
> correctly for some number of lines, and then lists garbage, look for a
> bad line pointer where the listing goes bad and poke in a value that
> corresponds to the start of the next line, one byte past a zero
> terminator.
>
> Most likely, all you'll need to do is alter the 3 pointers that start
> at $1B-C, which probably get reset to a couple of bytes past the
> program start value in $19-1A when an IO error occurs.
>
> Good luck!
>
> Art
>
> On Thu, Sep 6, 2012 at 12:14 AM, Chad H <chadbh74 at hotmail.com> wrote:
>> I've played a little bit with the .mp3 file and the .wav.  Both have the
>> beforementioned audio drop out at the end...the same place my CoCo 2 gives
>> IO error when trying to CLOAD these.  I tried the CLOADM and it errored out
>> quickly, stating ?FM error so apparently not a ML program file.  The .mp3
>> version seemed to be slightly 'deeper pitched' than the .wav version, but
>> both attempted to load same file name "LAB.GIG."
>>
>> Ran files through some filters and reshapers in Sony Sound Forge, especially
>> trying to normalize the volume at the dropout, but nothing that works yet.
>> It almost sounds like the tape may have briefly slowed down at that point
>> too..like maybe due to tape bind.  That would throw off the data timing I
>> suspect if so.
>>
>> -----Original Message-----
>> From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
>> Behalf Of Stephen H. Fischer
>> Sent: Wednesday, September 05, 2012 10:49 PM
>> To: CoCoList for Color Computer Enthusiasts
>> Subject: Re: [Coco] Recovering a damaged cassette file
>>
>> Hi,
>>
>> One point of interest, I see a difference between the
>> www.yaccs.info/MyDoD.jpg and the files
>>
>> http://www.yaccs.info/MyDoD/MyDoD.mp3
>> http://www.yaccs.info/MyDoD/MyDoD.wav
>> http://www.yaccs.info/MyDoD/MyDoD.aup.zip
>>
>> I am not sure that they are even the same audio recording.
>>
>> More data would be helpful.
>>
>> What computer, CoCo 2 or CoCo 3.
>>
>> And more about what the recording is, BASIC, Data or CLOADM?
>>
>> SHF
>>
>> Can some one please clue me into how to input the wav into VCC, I think I
>> had it right but the tape moved, AUDIO ON had no sound and nothing happened.
>>
>>
>> ----- Original Message -----
>> From: "Chad H" <chadbh74 at hotmail.com>
>> To: "'CoCoList for Color Computer Enthusiasts'" <coco at maltedmedia.com>
>> Sent: Wednesday, September 05, 2012 8:11 PM
>> Subject: Re: [Coco] Recovering a damaged cassette file
>>
>>
>> I was going to give this a try...or has someone already recovered it for
>> you?
>>
>> -----Original Message-----
>> From: coco-bounces at maltedmedia.com [mailto:coco-bounces at maltedmedia.com] On
>> Behalf Of Diego Barizo
>> Sent: Tuesday, September 04, 2012 11:07 PM
>> To: CoCoList for Color Computer Enthusiasts
>> Subject: Re: [Coco] Recovering a damaged cassette file
>>
>> I have uploaded the wav, MP3 and Audacity files
>> http://www.yaccs.info/MyDoD/MyDoD.mp3
>> http://www.yaccs.info/MyDoD/MyDoD.wav
>> http://www.yaccs.info/MyDoD/MyDoD.aup.zip
>>
>> Thanks to anyone who can give it a try.
>>
>> Diego
>>
>>
>> Luis Fernández wrote:
>>> I use the same editor
>>> wav utility can read my partial and rescue far as it goes.
>>> if you want to send me the wav and try to salvage what you have
>>>
>>> ----------------------------------------------------------------------
>>> -----------
>>> Making
>>> CoCoDskUtilPack V 1.1.3A.zip, Scan magazines and organize maltedmedia
>>> http://cococoding.com/cocodskutil/ Thank Aaron Wolfe
>>> http://www.tandycoco.com Thank Brian Blake and Stephen Fischer My
>>> personal blog: http://www.luis45ccs.blogspot.com,
>>> Excuse my English, I use google translator, my language is Spanish,
>>> I'm Spanish but I live in Venezuela
>>> ----------------------------------------------------------------------
>>> -----------
>>>
>>>> Date: Tue, 4 Sep 2012 22:07:00 -0300
>>>> From: diegoba at adinet.com.uy
>>>> To: coco at maltedmedia.com
>>>> Subject: [Coco] Recovering a damaged cassette file
>>>>
>>>> I have a program saved on tape that I would love to recover.
>>>> The problem is that the tape as a "drop" near the end of the file.
>>>> Has anyone ever been able to recover, at least partially a damaged
>>>> cassette file?
>>>>
>>>> I was thinking about just copying and pasting a good section of the
>>>> file on top of the damaged one, using Audacity ( an audio editor )
>>>>
>>>> Any suggestions on what to do?
>>>>
>>>> In case it helps, here is a screenshot of the last section of the
>>>> waveform. You can see 2 drops, a small, sharp one first, and a bigger
>>>> one almost at the end.
>>>> www.yaccs.info/MyDoD.jpg
>>>>
>>>> Thanks to all,
>>>>
>>>> Diego
>>>>
>>>>
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