ImageDisk and TeleDisk are both very good DOS floppy imaging tools. See Dave Dunfield's website: http://dunfield.classiccmp.org/
the floppy tools: http://dunfield.classiccmp.org/img/

There's plenty of diskette imaging software for DOS - I mostly use DiskDupe and DskImage.

However - with a standard FDC - no software can preserve typical copy protection schemes.
For this, special hardware is necessary - eg. KryoFlux.

However - with a standard FDC - no software can preserve typical copy protection schemes.
For this, special hardware is necessary - eg. KryoFlux.

I dont understand this - Im mostly talking about (funny / interesting) copy protection. These are part of the actual software (e.g. "Dial a Pirate"). These have been removed from many copies that are available (legally and otherwise)
If however I make an image form the original software - it should be ok - right ?

Aui wrote on 2024-10-09, 04:09:

I dont understand this - Im mostly talking about (funny / interesting) copy protection. These are part of the actual software (e.g. "Dial a Pirate"). These have been removed from many copies that are available (legally and otherwise)
If however I make an image form the original software - it should be ok - right ?

No, it won't be OK.

With standard hardware, you can't make proper images of copy-protected diskettes.
Sometimes the imaging software will report read errors, sometimes it will complete the read - but if you write the image back to a diskette, the copy-protected program will detect it's not an original copy, and refuse to work.

That's why tools like KryoFlux were created - they allow to record the signal coming from the FDD "as is", without attempting to interpret it.

But wouldnt most Dos area software even encourage you to "make a backup" of your original disks? Can you elaborate a bit more on where "classic DOS games" on floppy had such strong physical copy protection.

Copy protection was implemented using different methods and sometimes a combination of them.
One method was documentation in the box that was difficult to share (code wheels, manual references, sheets readable only through a colored semi-transparent layer etc)
Another method was protection on the disk/media itself.

I believe by "funny / interesting copy protection, part of the actual software e.g. Dial a Pirate" you refer to the first category. If it doesn't implement additional protection methods then yes, you can simply create copies without the need for special software or hardware.

Grzyb is referring to cases where the copy protection is implemented on the disk.

In between there are some copy protected disks that can be copied with special software like Teledisk.

Grzyb wrote on 2024-10-09, 06:04:

That's why tools like KryoFlux were created - they allow to record the signal coming from the FDD "as is", without attempting to interpret it.

this! except dont touch KryoFlux itself, those weirdos had such bullcrap in EULA as "we own copyright to all data copied with our tool" 😁
Use https://github.com/keirf/greaseweazle
~$30 https://decromancer.ca/greaseweazle/

More details about DOS era copy protection in this fantastic series:
https://martypc.blogspot.com/2024/08/pc-flopp … -formaster.html
https://martypc.blogspot.com/2024/08/pc-flopp … -softguard.html
https://martypc.blogspot.com/2024/09/pc-flopp … electronic.html
https://martypc.blogspot.com/2024/09/pc-flopp … ult-prolok.html
https://martypc.blogspot.com/2024/10/pc-flopp … emag-xelok.html

Grzyb wrote on 2024-10-09, 06:04:

That's why tools like KryoFlux were created - they allow to record the signal coming from the FDD "as is", without attempting to interpret it.

Almost. To be pedantic, for an authentic magnetic flux recording the read head must be tapped directly and then digitized by an ADC.
Otherwise, the drive electronics will alter the signal coming from the read head. Amplifier stages, filters, noise etc.
So KryoFlux is not absolutely accurate, contrary to popular belief. There's still a lot to be desired.

Central Point made the first bit-by-bit/sector by sector floppy copy adapters ( Copy2pc) starting back in about 1986. The Deluxe Option with the Transcopy3 ASIC was a valuable tool that worked between the Floppy controller and the drive to read/write encrypted/copy protected disks accurately and allow making copies of such (not images of, but exact copies of), many companies back thru early 1990's used them internally to legally copy protected disks. The Kryoflux is just a modern version of same thing IMHO and yes they both do have some limitations. I happen to have a Copy2PC II Deluxe card from 1988-89 obtained from a company in early 1995 and it worked very well to dupe 5.25" protected disks back then, have not used it for near 20 years...

Wow, what a rabbit hole - I had no idea about how sophisticated these protection attempts were. Thanks for the read! It seems my idea of an eternal original disk image archive is not as easy as I thought...

Jo22 wrote on 2024-10-10, 00:00:

Almost. To be pedantic, for an authentic magnetic flux recording the read head must be tapped directly and then digitized by an ADC.
Otherwise, the drive electronics will alter the signal coming from the read head. Amplifier stages, filters, noise etc.
So KryoFlux is not absolutely accurate, contrary to popular belief. There's still a lot to be desired.

This enters gold plugs SPDIF cable territory. Data is digital, interface is digital and standardized. Copy is perfect if it generates same output on the standardized interface.

rasz_pl wrote on 2024-10-09, 10:37:

More details about DOS era copy protection in this fantastic series: https://martypc.blogspot.com/2024/08/pc-flopp … -formaster […]
Show full quote

More details about DOS era copy protection in this fantastic series:
https://martypc.blogspot.com/2024/08/pc-flopp … -formaster.html
https://martypc.blogspot.com/2024/08/pc-flopp … -softguard.html
https://martypc.blogspot.com/2024/09/pc-flopp … electronic.html
https://martypc.blogspot.com/2024/09/pc-flopp … ult-prolok.html
https://martypc.blogspot.com/2024/10/pc-flopp … emag-xelok.html

thanks for the shoutout! I've got more coming.

rasz_pl wrote on 2024-10-10, 04:48:

Jo22 wrote on 2024-10-10, 00:00:

Almost. To be pedantic, for an authentic magnetic flux recording the read head must be tapped directly and then digitized by an ADC.
Otherwise, the drive electronics will alter the signal coming from the read head. Amplifier stages, filters, noise etc.
So KryoFlux is not absolutely accurate, contrary to popular belief. There's still a lot to be desired.

This enters gold plugs SPDIF cable territory. Data is digital, interface is digital and standardized. Copy is perfect if it generates same output on the standardized interface.

jo22's point is less pedantic than it sounds.
This blog does a good overview, with an oscilloscope view of the signal from the drive read head:

https://scarybeastsecurity.blogspot.com/2020/06/

The exact amplification circuitry could differ from drive to drive - its quite possible that you'll get a slightly different kryoflux dump using different drive models, in the worst case that could mean the difference between a working image or not. It would be ideal to sample the source signal, the slopes up and down, more precisely than the sampling the square waves from the drive itself. But I think we're in the realm of "good enough" with kryoflux, except for extreme outliers. Anything that makes it more of an ordeal to capture an image reduces adoption, and it's vitally more important that more people dump disks than it is that we start re-doing dumps with some sort analog read-head-tapping contraption.

I've encountered a few kryoflux images that I haven't been enable to write back to a working disk - Cops Copylock II for starters - I am not sure if that's a result of a bad image, an incompatible drive, or me not picking the right option in the Greaseweazle software...

It should be noted that copy-protected diskettes were problematic already back in the era.
And I mean problematic for legitimate users, rather than pirates.

Copy-protection usually required the program to bypass the normal DOS/BIOS functions, and access the hardware directly - which often failed on non-standard hardware.
What worked fine in plain DOS, was often causing problems in more advanced OSes/multitaskers.

IIRC, when IBM wanted to demo Lotus 1-2-3 running on their brand-new PS/2 machines, they had to use a pirate copy - the original medium was copy-protected 5.25" floppy, but the PS/2 only had 3.5" drive 🤣

GloriousCow wrote on 2024-10-12, 23:22:

The exact amplification circuitry could differ from drive to drive - its quite possible that you'll get a slightly different kryoflux dump using different drive models, in the worst case that could mean the difference between a working image or not.

GloriousCow wrote on 2024-10-12, 23:22:

I've encountered a few kryoflux images that I haven't been enable to write back to a working disk - Cops Copylock II for starters - I am not sure if that's a result of a bad image, an incompatible drive, or me not picking the right option in the Greaseweazle software...

wouldnt that mean said floppy doesnt work on all drives = bad floppy, bad drive or very bad copy protection?

rasz_pl wrote on 2024-10-13, 10:30:

wouldnt that mean said floppy doesnt work on all drives = bad floppy, bad drive or very bad copy protection?

or does it mean very *good* copy protection if it is still giving us trouble in 2024? 😀