[Coco] Reading floppies with CRC error?

[Kandur]

Sounds good, I may try that.
As a first step, just want to dump the raw data into a binary file.
Later I can analyze it and hopefully extract the useful data.
This 5.25" floppy is 80tracks, DS, DD, 96tpi, 300rpm, os-9 format.
http://qdv.pw/coco/?p=128 

Kandur

Tuesday, August 19, 2014, 3:03:29 PM, you wrote:
> Sorry, my earlier reply was not even trying to answer your question...

> Yes, having one out of a backup set fail, is frustrating.  Since you've
> gone this far, you might get lucky tweaking the pre-amp (if one is
> available) of the floppy head?  I've not done something like that in
> decades...

> I'm not personally aware of something under OS9 which would try to "guess"
> what the sector contains and use that rather than giving up with the CRC
> error.

> Perhaps make an image, outside of OS9, hex edit it to recalc the CRC value
> and put that back into the image?

> Hope some of these thoughts might be useful; but, you've likely already
> considered them... I've been outside of OS9 too long.

> sk
> On Aug 19, 2014 5:45 PM, "Kandur" <k at qdv.pw> wrote:

>> Nick, you are talking about 'now' and the 'future',
>> I agree with you 100%, but my probem is from the 'past'.
>> In the good old days of the Coco-3's birth year, we had no
>> SD memory cards, or DVDs, cheap HDs were were just a dream.
>> We used, what we had, floppies. Interestingly, 24 out of 28
>> floppies remained in excellent conditions, two had signs of wear
>> and only one was bad. My guess is, that that one was an
>> overused, worn out floppy when I made the archive.
>> Shouldn't have used it, my fault.
>> Anyway, I used to have a program, that rescued bad floppies.
>> It just kept reading everything non stop, garbage and all.
>> Later I had one like this to read bad CDs.
>> This diskette had some Sculptor database and
>> procedure files of my music collections' catalogs.
>> Not terribly important, just somehow don't feel like
>> writing the missing procedure sources again.

>> Kandur

>> Tuesday, August 19, 2014, 11:56:05 AM, you wrote:
>> > On 20/08/2014 2:30 AM, Kandur wrote:
>> >> Reading floppies with CRC error?
>> >> http://qdv.pw/coco/?p=253

>> >> Kandur


>> > Floppies with those sort of scratches on the surface are a lost cause.
>> > The disk media has deteriorated over the years that the magnetic
>> > material has become flakey and unreliable to store data on.

>> > While you may be able to recover some files off it, I ask myself the
>> > question... is it worth it when almost all programs are available as a
>> > DSK disk image?

>> > Personal data is another story but that is why magnetic media needs to
>> > be periodically backed up onto new media every so often...but who goes
>> > to that bother?

>> > I don't even use a floppy drive anymore. My CoCo is floppy'less. I've
>> > invested in a controller that uses SD memory cards and I run disk
>> > images. Backups are easily performed by copying the entire SD card to a
>> > directory on my PC.

>> > It also has Drivewire support.

>> > Best investment I ever made for my CoCo.

>> > Nick

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