List of difficult to copy disks

[mr.vince]

Jim, it really does not matter if you use fancy formatting, facts are facts. Let me correct things for you:

"Preserving" means checking integrity and authenticity, both are essential and only integrity will allow you to do good copies with verify. This is what we do and what people can try themselves with C64 dumping to G64. I am not surprised SCP has issues with generations when doing copies: http://www.cbmstuff.com/forum/showthrea ... 278#pid278

Your major issue here is to underestimating the skills and knowledge of the community...

Not much comment to me they look the same
Therefore my advice cleanup the disk before sampling

All of the "superiority" wiped away with a q-tip.

Jean, thanks for those really interesting charts. I would bet we'd get the same - good - results with a sampling of 50ns and even 100ns. Can your software resample the data?

[DrCoolZic]

For cleaning I was holding the metal protector with a scotch tape and spining the disk with a paper clip but I like your solution
For cleaning I have used a cleaning solution for CD lens from Discwasher, INc FL USA. It evaporates very quickly so do not even have to wipe it.

For the disc you got me ... as I am lazzy I had not resampled with SCP
so here you are with clean disc

SCP-FF-Clean.JPG

SCP-FF-Clean-DiskLayout.JPG

[DrCoolZic]

Jean, thanks for those really interesting charts. I would bet we'd get the same - good - results with a sampling of 50ns and even 100ns. Can your software resample the data?

No but I intend to add the capability to read input to Discovery Cartridge with a sampling around 60 something ns.

[mr.vince]

Although I am very confident we all (minus 1) already know the upcoming result... a fine reason to subscribe to this topic. Thanks, keep up the good work!

[JimDrew]

Jim, it really does not matter if you use fancy formatting, facts are facts. Let me correct things for you:

"Preserving" means checking integrity and authenticity

No it doesn't. Look at every definition of "preserve" and "preservation" on the planet Earth. What you are doing is integrity checking of preserved data. There is a difference. I spent my entire childhood in museums helping to preserve tens of thousands of artifacts, as my father was director & currator of several museums in our area. I know real preservation.

I am not surprised SCP has issues with generations when doing copies: http://www.cbmstuff.com/forum/showthrea ... 278#pid278

I am not either, as I clearly stated in the thread and explained why. There is no post read manipulation done to the data. You stuck your foot in your mouth and tried to claim that the image posted by DrCoolZic was modified, and its not. Adding the post read normalization cures the generational copy issue.

Not much comment to me they look the same
Therefore my advice cleanup the disk before sampling

Yep, I told you it was important! ... and look at the SCP dump after cleaning - still superior to Kryoflux.

I can switch sampling rates with SCP on the fly, from 25ns to 100ns samples, in 5ns increments. Perhaps I should make that an option that is available? You *will* see a difference in the image data, and it only makes sense. If a bit cell time is 4001ns and you are sampling at a 50ns rate, that bit cell time will appear as 4050ns, and even with multiple reads of the same data there is no way for the hardware (or software) to know that it was only 1ns off from being 4000 instead of 4050. That's the reality.

[JimDrew]

OK, someone here does not understand how sampling works...

http://en.wikipedia.org/wiki/Nyquist%E2 ... ng_theorem

Someone here doesn't understand how the hardware works. It's pretty simple - when there is a high to low transition on the RDData line, a timer clock is cleared and started. When there is another high to low transition, the time is captured and stored. The timer used is based on the capture frequency, which in the case of SCP is 25ns. In the case of Kryoflux it is 41.66ns. So, the time value stored is either multiplied by 25 (SCP) or 41.66 (Kryoflux) to get the real time in nanoseconds. That's it. That's all there is to accumulating the flux data from the drive. What you do after the fact is where sampling and averaging comes in.

Bit cell entries (time) will be larger with SCP flux data because more captures occur. In 4000ns, SCP makes 160 captures. In 4000ns, Kryoflux makes only 96 captures. No matter how this attempts to get twisted, those are the facts. If higher resolution didn't matter for "preservation(sic)" then we would all still be using brownie box cameras.

[IFW]

As for being the exact multiple of something: it’s a complete misunderstanding of how sampling works at best... willful misleading of customers at worst.
Think about it...
- The drive writing the disk has speed x
- The drive reading the disk has speed y
- The bitcells move closer or farther away of their desired positions due to peak shifts, regardless of pre-compensation
- Bonus is any other delay in the system
The net result is that it does not matter what is recorded and how it is read neither will ever be an exact multiple of value Z.
You will get bitcells like 3.99767767, 4.0050656, etc. for real from the drive.
Obviously the numbers here are random, just like anything you read from the read line is not an exact multiple of ANYTHING, apart from the actual value being read.
If you are lucky, say 1 in a million times, you may get an exact multiple of <your favourite sampling frequency>.
Any other times you get aliasing, regardless of the sampling resolution used.

[IFW]

SPS have been involved in the preservation of digital artefacts with very well known institutes from all over the world.
While you may or may not have any sort of experience with preserving tin cans or books, or whatever else from your childhood, digital artefacts are a very different thing in which you have no real-world experience whatsoever.

[JimDrew]

Really? I was "preserving" disks long before you were... in fact, I was preserving tapes (cassette and reel to reel) before that.

My point about even multiples ties to the fact that there are nearly twice as many samples being taken by SCP compared to Kryoflux. Although there is drive speed variation through the entire revolution, there are still MANY times where a 4000ns turns out as exactly 4000ns (aliased to the maximum sample resolution of the drive), and when it does, the resulting data will be more accurately preserved using SCP than with Kryoflux.

I created SuperCard Pro because you guys are a bunch of jerks who think you know everything, and nobody else (even those with more experience) knows anything. People just don't like you guys because of your holy-than-thou attitudes. SuperCard Pro is a superior product in every respect... get over it.

[rittwage]

OK, someone here does not understand how sampling works...

http://en.wikipedia.org/wiki/Nyquist%E2 ... ng_theorem

Someone here doesn't understand how the hardware works. It's pretty simple - when there is a high to low transition on the RDData line, a timer clock is cleared and started. When there is another high to low transition, the time is captured and stored. The timer used is based on the capture frequency, which in the case of SCP is 25ns. In the case of Kryoflux it is 41.66ns. So, the time value stored is either multiplied by 25 (SCP) or 41.66 (Kryoflux) to get the real time in nanoseconds. That's it. That's all there is to accumulating the flux data from the drive. What you do after the fact is where sampling and averaging comes in.

Bit cell entries (time) will be larger with SCP flux data because more captures occur. In 4000ns, SCP makes 160 captures. In 4000ns, Kryoflux makes only 96 captures. No matter how this attempts to get twisted, those are the facts. If higher resolution didn't matter for "preservation(sic)" then we would all still be using brownie box cameras.

This is the exact opposite comparison. In your Brownie box example, you are taking a picture of something very high resolution using something with a much lower resolution, and in that case it makes sense to increase your "Brownie Box" technology to take better pictures. However, in this case you are taking pictures of something of very low resolution using something of much higher resolution. In that case, it won't matter how much better your capture device is, you end up with the same picture.

[mr.vince]

Right, you created man before God.

You stuck your foot in your mouth and tried to claim that the image posted by DrCoolZic was modified, and its not.

Which it is. Now both graphs are processed. DrCoolZics software does PLL processing for the disk view, which obviously does not work on bad reads (or only partially), but looks nice on good reads. If you'd not have such an ego problem, and would question things, you'd maybe see the facts. Now both are looking to good to come directly off a real disk. The scatter graphs show the actual data. There's basically the same data coming from both devices.

[DrCoolZic]

May I suggest to cool down
This discussion is going nowhere and there is obviously no hope that you would agree on something.
So please lets return to the subject of the threads
Thanks

[IFW]

No, you made this because - just like old times - you saw a window of opportunity to make some easy money and work your way through problems by deceiving people.

[bullis1]

Yeah seriously can the SPS people (IFW & mr.vince in this case) back off or go argue via PM?

[JimDrew]

Why don't you go play in your forum? You don't see me posting in there, do you? #HAVERESPECT

[IFW]

Well, what do you honestly expect to happen when you call people names...?
Anyway, enough time wasted... for everyone.

[AtariZoll]

I can say only that as in almost everything, here is also different approach to the subject. Since both projects - KryoFlux and SuperCard Pro are still not finished , and I guess that much more work on SW is needed than on HW (as usual), just let that time decide which is better. And as is usual, it may happen that we will have no answer for that - some people will prefer one, some other.
People wants results, something useful (and we know what is it here), so both sides please continue your fascinating work.

[DrCoolZic]

FYI I have started a new thread on quality of imaged diskettes http://www.atari-forum.com/viewtopic.php?f=95&t=25934

[JimDrew]

I got Theme Park Mystery and Dragonflight in today. Both copy and image perfectly.

So, at this point "Crown Of Creation 3D" remains as the only program that is suppose to be difficult to copy that I have not yet seen. Does anyone have this program?

[Zogging Hell]

I got Theme Park Mystery and Dragonflight in today. Both copy and image perfectly.

So, at this point "Crown Of Creation 3D" remains as the only program that is suppose to be difficult to copy that I have not yet seen. Does anyone have this program?

16/32 were the distributors of this I think, so you might want to try that website as they are still going, it's listed on there with original retail price of £24.99 (or thereabouts).

[JimDrew]

Thanks, I sent an email to 16/32 to see if an original is still available. I don't have a Falcon to test the disk, but I am looking for one.

[DrCoolZic]

Does that mean that you can now copy Turrican ?
When will we get the Firmware update ?

[bullis1]

There is a good chance I'm mistaken here, but I thought that Crown of Creation wasn't difficult to copy due to the disk's format, but rather due to DSP-based protection that has remained un-cracked? Or does the system use both methods in tandem?

[JimDrew]

Does that mean that you can now copy Turrican ?
When will we get the Firmware update ?

I have not hooked up the logic analyzer to the Amiga yet to see how the strongbits is written out with the Amiga (correctly, I might add). I am working on the disk utils at the moment and I fixed a few C64 issues. I am bouncing back and forth between format types as bugs are reported.

Once I see how the Amiga writes strongbits, I can then experiment with the duration of the pulse pattern so I can convert the total strongbits time into the proper number of pulses to perfectly replicate the NRZ duration for the protection used in Turrican, Ghostbusters II, Ivanhoe, etc. So, perhaps over the weekend I can get the Amiga connected to the analyzer and figure it out.

[alexh]

I got Theme Park Mystery and Dragonflight in today. Both copy and image perfectly.

Out of interest, how do you test this? Can you somehow test for a 100% accurate duplication?

The disk copy protection test in Dragonflight occurs quite late into the game.