Apple II disk Grrr.....

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IFW
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Re: Apple II disk Grrr.....

Post by IFW » Sat Feb 10, 2018 6:04 pm

Cosmo wrote:
Mon Feb 05, 2018 6:07 pm
I am reading the original factory pressed disks as:

Code: Select all

dtc -dd0 -p -a8 -f"TitleName/TitleName_" -i0 -g2 -y -i8 -l8 -t10
Have you checked whether your drive requires -dd01 or -dd1 to switch the filtering to DD mode?
It can matter a lot for A2 disks and with the incorrect mode some dumps may end up unusable... what you need is to find the correct DD mode.
Short version: filtering specifically intended for HD disks does not tolerate flux reversal periods that are longer than what a HD MFM encoded data should contain, and turns up the AGC. This in turn introduces fake flux reversal signals, rendering the data read full of errors - there is no way to recover the real, DD flux reversals.
The density mode (-dd?) matters a lot on some drivers, not a big difference on others, and on some drives it does not work at all... so it's always a good idea to test first what works best on YOUR drive. (even different steppings of the same manufacturer/model might behave differently)

Rakki
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Re: Apple II disk Grrr.....

Post by Rakki » Sun Feb 11, 2018 9:22 pm

Cosmo, here are instructions how to test -dd0 / -dd1 for your drive:
https://forum.kryoflux.com/viewtopic.ph ... 8101#p8101

Cosmo
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Re: Apple II disk Grrr.....

Post by Cosmo » Thu Feb 15, 2018 8:26 am

Rakki & IFW
Tested the "Victory Road-Ikari Warriors 2" orignal with these parametres and the folder size was as:

dtc -dd0 -p -a8 -f"TitleName/TitleName_" -i0 -g2 -y -i8 -l8 -t10 -> 33.1MB
dtc -dd1 -p -a8 -f"TitleName/TitleName_" -i0 -g2 -y -i8 -l8 -t10 -> 28.9MB

With DD0 error with tracks 20,34
With DD1 No errors on tracks at all.

So i should be useing DD1 setting instead then?

Rakki
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Re: Apple II disk Grrr.....

Post by Rakki » Thu Feb 15, 2018 11:50 am

Yes, DD1 is correct for DD disks in your case. DD0 works better for 5.25” HD floppies.

IFW wrote ”This is due to the reduced noise level from unformatted tracks in DD mode.”. Smaller size stands for DD in this case.
Last edited by Rakki on Thu Feb 15, 2018 1:49 pm, edited 1 time in total.

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IFW
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Re: Apple II disk Grrr.....

Post by IFW » Thu Feb 15, 2018 1:40 pm

...and last, but not least, do you have all the tracks for side 0/1? (check the log/output, they should both contain logical track 0) There are 2 different flippy mod types and they require different physical track offset parameters otherwise some of the early tracks will be missing (due to head offset present in double sided drives).

Feel free to post a test image of a double-sided flippy disk if needed.

ZrX
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Re: Apple II disk Grrr.....

Post by ZrX » Thu Feb 15, 2018 2:51 pm

It's a drive I flipped. :)

Cosmo
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Re: Apple II disk Grrr.....

Post by Cosmo » Thu Feb 15, 2018 3:41 pm

Some test dumps made now & uploaded. Let me know if they are ok so i'll get them all done in same way.

Dominus
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Re: Apple II disk Grrr.....

Post by Dominus » Fri Apr 27, 2018 12:14 pm

So, to recap, you can dump them and almost all tracks will show as unformatted in the log (i have a newtronics flipped drive). And you cannot test the dumps, because the raw dump doesn't convert correctly.
Right?

A bummer because I have a rare Ultima (1) disk that is a pre release of the original California Pacific release.

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IFW
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Re: Apple II disk Grrr.....

Post by IFW » Fri Apr 27, 2018 12:40 pm

Any kind of standard A2 disk can be decoded/verified fine, copy-protection related data or custom formats will need user defined formats for decoding.
However, with DTC 2.72 or later you can use the consistency graphs to see the sample quality of the dump you made (thus know whether the disk should be cleaned/redumped etc) and that requires no decoding whatsoever.

Dominus
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Re: Apple II disk Grrr.....

Post by Dominus » Fri Apr 27, 2018 3:22 pm

hmm, I am on OS X... so no 2.72 for me... time to dig out the old XP laptop...

Edit: hmm, last version dropped XP support... that seems to get interesting :)

Also, what is the correct dtc command to convert the raw dump to a dsk image?

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