copy-protected 3,5" DOS Floppies & Kryoflux

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frank128
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copy-protected 3,5" DOS Floppies & Kryoflux

Post by frank128 » Tue Dec 08, 2015 3:22 pm

Beside of copy protected Commodore games I run into copy issues with the DOS Game "Lemmings" from PSYGNOSIS from 1991. Looks also DOS had it's good copy protection. These comments I've found in the Internet related to the "Lemmings" game from 1991:
  • "To copy Lemmings from original to other disks, Copy II PC Option Board must be needed with weak bit support.
  • "Lemmings can't be copied to other disk without Trans Copy Option Board. ... But it can be run on PCE emulator with TD0 format."
  • "Lemmings / 1st rivision / Weak bit Copy Protection on Track 0-0"
Is it possible to copy the 3,5" Floppy via Kryoflux. I've tried it but the copied Floppy does not work. The game asked for the original disk.

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mr.vince
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by mr.vince » Tue Dec 08, 2015 6:27 pm

Weak bits can't be copied without parameters or modifying the data. That's the reason weak bits are used. You could modify the raw dump for the particular track and inject weak bit data for writing... Or create a temp IPF. To my knowledge Lemmings is DD not HD.

frank128
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by frank128 » Wed Dec 09, 2015 3:31 am

mr.vince wrote:Weak bits can't be copied without parameters or modifying the data. That's the reason weak bits are used.
the old ISA card "Central Point Deluxe Option Board" with "Transcopy" as software component seems to be able to copy Lemmings with its weak bits copy protection.

http://retro.icequake.net/dob/
The Option Board is an add-in disk controller for the IBM PC that can defeat weak-bits schemes, custom formats, long tracks, you name it. 99% of floppies with disk-based protections made before 1990 can be duplicated perfectly by the Option Board

...

Transcopy stands for "Transition Copier", which describes how it works; it simply copies the flux reversals (transitions) on the disk, without a care as to what the data on the disc actually is.
Where is the problem on the Kryoflux side? Maybe the ancient Transcopy program needs dedicated parameter for the copy protected Lemmings floppy?
mr.vince wrote: You could modify the raw dump for the particular track and inject weak bit data for writing...
Which tools I can use to do this?
mr.vince wrote:To my knowledge Lemmings is DD not HD.
Correct

Why I'm asking this? I've bought a original Lemmings 3,5" DD Floppy and play Lemmings on a real 486'er PC. I want to protect the original foppy. Copy the original floppy to an image file and run the game on an emulation is not in scope! If the old Central Point ISA Card was able to copy the game in an easy way why not Kryoflux?

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mr.vince
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by mr.vince » Wed Dec 09, 2015 8:08 am

Maybe because KryoFlux is an imaging device made for preservation whereas the product you mention is a copier that on purpose modifies (!) data read (maybe even detects the protection and disables it - which is illegal today as per DMCA). It's really clearly communicated and documented what KryoFlux does.

The sole purpose of weak bits is to read differently than written. One can guess by looking at a couple of revolutions and then modify the raw data. I am afraid there's no known tool apart from our own Analyser and Keir's Disk Utilities which create IPFs. The latter is free and open source. That would be the easiest way to do it.

frank128
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by frank128 » Wed Dec 09, 2015 9:05 am

mr.vince wrote:I am afraid there's no known tool apart from our own Analyser
Where can I get this Analyser?

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IFW
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by IFW » Wed Dec 09, 2015 11:54 am

Yes, many of those programs detected the protection type and "patched" either the code or the data.
If Lemmings PC uses a variable bit rate (like the Amiga version) then it should copy fine with any recent KryoFlux software release.
If your Lemmings disk is using weak bits or NFAs, you'll need the next update of the KryoFlux software to replicate it - which will be released soon :)

Please note, that the KryoFlux host software does not "patch" the data or the code; it replicates the disk as is.

frank128
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by frank128 » Wed Dec 09, 2015 1:05 pm

IFW wrote:Yes, many of those programs detected the protection type and "patched" either the code or the data.
OK, but the ancient "CopyIIPC Option Board" ISA card and the related Transcopy software

"it simply copies the flux reversals (transitions) on the disk, without a care as to what the data on the disc actually is."

seems to act similar to Kryoflux and do not do any patching.
IFW wrote: If your Lemmings disk is using weak bits
It does
IFW wrote: or NFAs, you'll need the next update of the KryoFlux software to replicate it - which will be released soon :)
sounds good. I will test it with the next Kryoflux update

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mr.vince
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by mr.vince » Thu Dec 10, 2015 8:12 am

It is impossible to replicate weak bits without altering the data - it reads back differently than it was written. I am very confident that if we look at Transform source there is handling of weak bits. Maybe even more... A lot of programs back in the day had hidden detection and removal of copy protection schemes. Again, impossible to copy " as is".

The Analyser you are asking for is an institutional tool with a very different price tag. It's not available for consumers.

ZippyZapp
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by ZippyZapp » Tue Dec 22, 2015 6:18 pm

I would like to know this too as I would also like to backup lemmings. I am confused though as one of you is saying it may be able to work in the next release and the other is saying it is impossible. So which is it? ;)

I don't care if the copy is protected too as in an exact clone I just care that it can be backed up.

Thanks!

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mr.vince
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Re: copy-protected 3,5" DOS Floppies & Kryoflux

Post by mr.vince » Wed Dec 23, 2015 8:59 am

Weak bits in general are impossible to copy as is. They read back differently than they are written.

Whatever feature is coming: from the product description KF is an imaging device this is what matters (to us). As good is it is and will be in regard to writing we will never advertise or guarantee any cloning abilities.

KryoFlux can perfectly write any data - if it's correctly described. The format description for KF raw stream is open. The IPF decoder is open. Just program your own raw stream or IPF and it will perfectly be written to disk. Yes, you will need to know or learn about floppy coding for this.

EDIT: Regardless of if you care about it KryoFlux will never crack or modify data. This is not what preservation stands for and it's illegal in most countries. Period.

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