Atari ST Protection Techniques Special Edition

A forum about Atari protected floppy disks analysis, preservation, emulation, tools

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DrCoolZic
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

About recovering dead disk I do not know if you are aware of the Work of Josha Beukema.
if not you MUST have a look here http://makercentral.net/

He has done a very interesting application that allow you to recover dead disk (For information his code uses my DPLL from Aufit.
Note that the application now read SCP and KF raw files.
Look at the FloppyControlApp videos at https://www.youtube.com/channel/UCJSWen ... J9w/videos

The FloppyControl project is open source it contains sources for the hardware, the software, and a cleaning kit …
https://github.com/imqqmi/FloppyControl
The readme file contains lots of useful information

By the we do not have SCP or KF file of ST diagnostic?
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Re: Atari ST Protection Techniques Special Edition

Post by rcamp48 »

Ya no problem, its on my Mega Site
Now supporting Atari Portfolio , my archives are still being maintained.
BBS is now up again as an Atari BBS, run on PC, cause I sold everything but my Atari Portfolio.
Note: Atari Portfolio IDE CF kits are being made. Get yours today! :megaphone:
Note that my BBS is back online with Win-server 8.0454.8 at telnet://spyvisitsspybbs.com:1990 and http://www.spyvisitsspybbs.com:1991
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

Link to your Mega site?
the https://mega.nz/#F!sclxnCaA!emBXJkA0xxDAPz2gllJaqQ link is dead ?
rcamp48
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Re: Atari ST Protection Techniques Special Edition

Post by rcamp48 »

Ok I will get it this morning....
Russ

https://mega.nz/#F!oc8VgAqT!kPgl_GUF-3z4ze9rJL6W8Q
Now supporting Atari Portfolio , my archives are still being maintained.
BBS is now up again as an Atari BBS, run on PC, cause I sold everything but my Atari Portfolio.
Note: Atari Portfolio IDE CF kits are being made. Get yours today! :megaphone:
Note that my BBS is back online with Win-server 8.0454.8 at telnet://spyvisitsspybbs.com:1990 and http://www.spyvisitsspybbs.com:1991
rcamp48
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Re: Atari ST Protection Techniques Special Edition

Post by rcamp48 »

Now supporting Atari Portfolio , my archives are still being maintained.
BBS is now up again as an Atari BBS, run on PC, cause I sold everything but my Atari Portfolio.
Note: Atari Portfolio IDE CF kits are being made. Get yours today! :megaphone:
Note that my BBS is back online with Win-server 8.0454.8 at telnet://spyvisitsspybbs.com:1990 and http://www.spyvisitsspybbs.com:1991
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Re: Atari ST Protection Techniques Special Edition

Post by TomH »

I assume you'd have no problem with someone uploading the PDF to archive.org?
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

Thanks. I am particularly interested by the manual. I might find interesting information for my document @ http://www.atari-forum.com/viewtopic.php?f=104&t=21952
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

TomH wrote:I assume you'd have no problem with someone uploading the PDF to archive.org?
I have created a clean and searchable version of the documentation.
You may want to use this version for archive.org ?

Can be accessed here https://mega.nz/#!Fh4mSawA!bcf8Puwskuii ... WMjQyX6Sag

Jean
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Re: Atari ST Protection Techniques Special Edition

Post by TomH »

DrCoolZic wrote:
TomH wrote:I assume you'd have no problem with someone uploading the PDF to archive.org?
I have created a clean and searchable version of the documentation.
You may want to use this version for archive.org ?

Can be accessed here https://mega.nz/#!Fh4mSawA!bcf8Puwskuii ... WMjQyX6Sag

Jean
Fantastic, thanks! Uploaded, so I very much hope that isn't stepping on anyone's toes. It's here for download, and I assume the in-browser preview will appear once archive.org has processed the thing.

So far I've only skimmed it, but I don't think it covers anything in terms of disk encoding that you don't already cover in much more detail.

In case it's any help at all, the only question mark I was left with is what a WD would return from a read track when hitting a false sync. At that stage in the pipeline I had in my head a simple model of a 16-bit shift register, with both a down counter so that it outputs a byte every 16 shifts, and sync pattern detectors that can reset the counter. But some STX files — a really convenient source for comparing what a read track produced compared to what was in sector bodies — provisionally appear to have output that doesn't fit that model.

Or else my means of investigation is faulty. But the main point is that your document doesn't quite explicitly say. It covers how a false sync can occur, that it will cause a resynchronisation, and the pattern that the standard $00s followed by a triple $A1 will produce, but isn't fully explicit on what other output a resynchronisation might produce as a byproduct.

Though definitely don't rule out that I just don't know how to read.
Last edited by TomH on Tue Jan 21, 2020 10:27 pm, edited 1 time in total.
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

You are right the decoding of synch mark is very complex and need to be better documented. Originally Aufit was not decoding some sync configuration correctly. Details of the wd shifter can be found in the sps decoder library source code ...
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Re: Atari ST Protection Techniques Special Edition

Post by TomH »

Thanks for the tip! I don't have time to read it in depth now, but I guess that CapsFDCEmulator.cpp:FdcShiftBit is the thing to start with. I'll stick my nose in there.
Last edited by TomH on Wed Jan 22, 2020 3:47 pm, edited 1 time in total.
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Re: Atari ST Protection Techniques Special Edition

Post by orionfuzion »

Bonjour Jean,

Do you know the protection used on Audio Sculpture? (STX available here: http://defence-force.org/download/atari ... ure1-5.zip)
The author (for the physical part) is Altaïr/VMAX (also author of the Atomik packer).
He described the principle of this protection here: http://www.atari-forum.com/viewtopic.ph ... 25#p330115 (the rest of the thread provides additional details).
Looks like it's a very unusual technique (at least on Atari) and it probably deserves to be in your "Atari Floppy Disk Copy Protection" documentation.
The software part is also amazing (work done by Illegal+Altaïr+Zarathustra+guys from SYNC)... I'm currently writing a brief documentation on this part.

Orion/Sebastien
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

I just read the Audio Sculpture thread. Very very interesting. I have not worked/looked at Atari stuff for quite some times and I missed this thread. Yes this protection needs to be analyzed further. I have used Aufit (in progress version) to look at the protection and Aufit seems to be confused in many places. I think that track 3 uses other protection not described. I will also try to test under SPS CTA analyser (need to reinstall HW protection) to see how CTA interprets track 3 …
Interested in reading your documentation.
The thread on Audio Sculpture contains lots of information about the protection as well as emulation problems. Would be nice to extract in a doc information related to protection only.
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Re: Atari ST Protection Techniques Special Edition

Post by DrCoolZic »

If interested I restarted the thread about Audio Sculpture http://www.atari-forum.com/viewtopic.ph ... ad#p392018
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