Dumping Eye of the Beholder PC problems (copy protection)?

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robbo007
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Location: Valencia, Spain

Dumping Eye of the Beholder PC problems (copy protection)?

Post by robbo007 » Thu May 16, 2019 10:31 pm

Hi all,
I'm trying to dump and write the stream files to a new floppy to test it all working. The first floppy looks copied fine but when I run the install command and it starts it hangs my system.

I get bad sector from 00.0 to 00.2. The original disk installs fine and does not hang my system.

I'm using to dump:

dtc -fname -i0 -i2 -v300 -d1 -fname.img -k2 -i4

to write to my new floppy:
dtc -w -wi4 -fname

Could this just be a bad disk?
Last edited by robbo007 on Fri May 17, 2019 1:31 pm, edited 1 time in total.

robbo007
Posts: 58
Joined: Wed May 23, 2012 2:56 pm
Location: Valencia, Spain

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by robbo007 » Fri May 17, 2019 1:26 pm

I seem to get something simular on disk 4 of Tangled Tales too. The dump seems to produce no errors but when installing the game on the last disk I get sector errors. I've tried it on two different drives now and the same. Does not look like a floppy issue. Very strange.

ZrX
Posts: 530
Joined: Tue Dec 06, 2011 9:09 pm

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by ZrX » Fri May 17, 2019 2:35 pm

Try writing with just -w -fname to write back the raw files.

EOTB should be manual protection so writing should work just fine.

SomeGuy
Posts: 218
Joined: Wed Feb 18, 2015 8:18 pm

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by SomeGuy » Fri May 17, 2019 2:59 pm

Copying using flux streams will introduce additional "noise" on the copy. So it could be a marginal read error from the original either due to minor damage on the original disk or some minor anomaly in the way the disk was written. The original may read fine in a real drive or decode with the kryoflux but the small amount of noise introduced by writing a copy may push readability just over the edge.

The best way to be sure is to post your dumps for others to look at. You might be able to spot "noise" by looking at the histogram plot. Sometimes just cleaning a spot or two on the disk with a wet q-tip and a few redump retries will fix the problem. But if the disk is badly worn or was mastered badly, that won't help.

A quick search for "Beholder PC" suggests that uses a document check copy protection rather than disk based copy protection. In that case you should be able to either take your decoded IMG file to a PC with a floppy and write it with a tool like WinImage, or you can create a clean flux image by loading the IMG file in to the HxC software tool and saving as a Kryoflux flux stream.

I'm guessing you are using a 360k drive for both, but just a reminder that 360k disks written in a in a 1.2mb drive may not be readable in a genuine 360k drive.

Unfortunately, there is no media testing tool for the Kryoflux to test target disks for errors before writing.

robbo007
Posts: 58
Joined: Wed May 23, 2012 2:56 pm
Location: Valencia, Spain

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by robbo007 » Fri May 17, 2019 5:49 pm

SomeGuy wrote:
Fri May 17, 2019 2:59 pm
Copying using flux streams will introduce additional "noise" on the copy. So it could be a marginal read error from the original either due to minor damage on the original disk or some minor anomaly in the way the disk was written. The original may read fine in a real drive or decode with the kryoflux but the small amount of noise introduced by writing a copy may push readability just over the edge.

The best way to be sure is to post your dumps for others to look at. You might be able to spot "noise" by looking at the histogram plot. Sometimes just cleaning a spot or two on the disk with a wet q-tip and a few redump retries will fix the problem. But if the disk is badly worn or was mastered badly, that won't help.

A quick search for "Beholder PC" suggests that uses a document check copy protection rather than disk based copy protection. In that case you should be able to either take your decoded IMG file to a PC with a floppy and write it with a tool like WinImage, or you can create a clean flux image by loading the IMG file in to the HxC software tool and saving as a Kryoflux flux stream.

I'm guessing you are using a 360k drive for both, but just a reminder that 360k disks written in a in a 1.2mb drive may not be readable in a genuine 360k drive.

Unfortunately, there is no media testing tool for the Kryoflux to test target disks for errors before writing.
ok that makes sense. The disk is not in the best of shape. But the master does read and install fine on a IBM 5170. Is there any way to reduce this "noise" when using flux streams?

So should I use 97 proof cleaning alcohol on the q-tip? Or will this destroy the disk? I've downloaded HxC floppy emulator. Is this what you mean? There is an option to "Track Analzyer" which shows the stream and I see red bacd CRC parts. Unfortunately using Winimage does not cure the problem.

I'm using a 1.2MB drive to dump my stuff and the diskettes are 360kb. On the real computer I've tested the copied disks with a 1.2MB and a 360K drive. Both show simular symptoms.

I would like to know what I'm looking for when looking at the track analyser. I'm afraid I'm too new at this to make any progress. Any suggestions for reading up on this so I can understand what is really going on behind the scenes ?

SomeGuy
Posts: 218
Joined: Wed Feb 18, 2015 8:18 pm

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by SomeGuy » Fri May 17, 2019 11:13 pm

Only use isopropyl alcohol as "the big guns" if needed. Just start with water and clean any visible spots or grime on the disk. Sometimes, tough sticky spots requires alcohol, but isopropyl alcohol has a tendency to remove oxide on flaking or scratched disks. Off hand, I would not recommend anything higher than typical store bought 91% (I have not tried higher stuff myself, but I have heard that can be too tough).

On a non copy protected disk 360k, the HxC software should simply show 9 sectors radiating from the center and on both side. All sectors should be colored green to indicate they are readable. Red spots indicate problems with the flux (tiny red specs at the beginning or end of a sector are normal) and orange indicates a bad sector CRC.

Ideally, you want to get a flux dump with as few red spots as possible, and all sectors green.

If you see orange/bad CRC sectors but no red anywhere, that indicates copy protection. (The sectors are intentionally bad).

Oh, also don't forget, if you used a 1.2mb drive to read a 360k disk but read all 80 tracks, you need to delete all odd tracks. Otherwise you just see a lot of junk on the unused tracks. When dumping, make sure you have the track spacing set correctly so it double steps.

You might try dumping the disk with an actual 360k drive. Sometimes damaged disks can read more reliably in a 360k drive than a 1.2mb drive. (Although sometimes the opposite is true depending on the damage). Personally, I prefer to dump 360k disks in a real 360k drive, but when dumping a lot of unknown disks many people prefer just using a 1.2mb drive as it helps ensure they get all the bits.

Aside from getting a better flux stream dump, the only way to eliminate noise is to reduce to its "lowest common denominator". On an standard, non-copy protected IBM PC disk that is an IMG sector file. I'd talk about copy protection, but that's going down a deep rabbit hole there. :)

robbo007
Posts: 58
Joined: Wed May 23, 2012 2:56 pm
Location: Valencia, Spain

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by robbo007 » Sun May 19, 2019 10:16 pm

SomeGuy wrote:
Fri May 17, 2019 11:13 pm
Oh, also don't forget, if you used a 1.2mb drive to read a 360k disk but read all 80 tracks, you need to delete all odd tracks. Otherwise you just see a lot of junk on the unused tracks. When dumping, make sure you have the track spacing set correctly so it double steps.

You might try dumping the disk with an actual 360k drive. Sometimes damaged disks can read more reliably in a 360k drive than a 1.2mb drive. (Although sometimes the opposite is true depending on the damage). Personally, I prefer to dump 360k disks in a real 360k drive, but when dumping a lot of unknown disks many people prefer just using a 1.2mb drive as it helps ensure they get all the bits.

Aside from getting a better flux stream dump, the only way to eliminate noise is to reduce to its "lowest common denominator". On an standard, non-copy protected IBM PC disk that is an IMG sector file. I'd talk about copy protection, but that's going down a deep rabbit hole there. :)
So if I use the parameter -k2 for a 360kb 5 1/4" MFM disks. Is that what you mean by setting the track spacing? I see it seems to read the 80 tracks of the 360kb disk even through I've specified 40 tracks.

Should I be using the -dd value as Low or high?

I've read it's better to play with disk images in device-less mode? if this is the case should the first dump from floppies only use these parameters dtc -fname -i0 ?

Please go on about copy protection (PC based) as its good to have this information saved for future reference.

Cheers,
Rob

SomeGuy
Posts: 218
Joined: Wed Feb 18, 2015 8:18 pm

Re: Dumping Eye of the Beholder PC problems (copy protection)?

Post by SomeGuy » Mon May 20, 2019 3:15 pm

Yes, -k2 is the way to speicfy double stepping from the DCT program.

-dd is a very confusing command because it refers to the the digital logic line level rather than the density itself.

-dd0 = logic line low = High Density on normal PC drives
-dd1 = logic line high = Low Density on normal PC drives
note: A few non-IBM PC 1.2mb drives have the logic line signal reversed. (Is why KF refers to logic line)
note: Ignored if a genuine 360k 5.25 or 720k 3.5" drive is in use.
note: Ignored by most, but not all, 1.44mb 3.5" drives in favor of the density notch.
note: Setting logic high (low density) with a high-density notched 3.5" disk may engage 360RPM "Japanese mode 3" on some 3.5" drives.

If you don't know what is on a disk or want to ensure you get all bits without analyzing the image, then yes, dumping all 80 tracks the first time may be preferable. But for analysis and decoding purposes you want a copy without the odd numbered tracks or you can make a mess decoding garbage.

Most of my notes about copy protection are written elsewhere and I don't want to bog down this thread. I wouldn't really be able to tell unless you posted a stream file anyway.

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