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The Mr. Video

Dumping a Disk with bad Sector Copy Protection.

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Hi, recently I bought a copy of Gorf on floppy disk. Atari Mania only has the cartridge version on archive, so I figured I'd chip in and dump my copy. The problem is that the disk has bad sectors spaced equally between good sectors, and the game loads fine otherwise, which makes me think that the disk has intentionally bad sectors as a means of copy protection. Using SIO2USB + Disk Wizard II doesn't seem to work, as attempting to load the dumped copy would result in the computer soft-locking on sector 16. Is there a way to copy the disk while retaining the all the bad sectors from the source disk?

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Disk Wizard II will merely result in a copy with all data that was readable still intact. Bad sectors may contain "some" information in the copy, but will only be useful for someone attempting to crack it.

 

It's best to send it to someone familiar with the process to flux image it with a Kryoflux or SuperCard Pro if you dont acquire one yourself. This will capture the disk in the best possible format for preservation, and for conversion to .ATX - a compact disk format that preserves copy protection usable by drive emulators.

 

To see the exact bad sectors and possibly duplicate the protection, you can see where they are with modified drives on real hardware such as archiver 810, 1050 archiver II, Happy 1050 with archiver/chip emulation, or a Speedy 1050.

 

Actually, having written all that I just checked a recent list of "verified" software in the Atari 8-Bit preservation initiave, and the Gorf disk is on the list. So, good news - it's already been preserved, it just hasn't made it onto AtariMania yet! Check that thread for the latest download release that should include it.

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6 minutes ago, Nezgar said:

It's best to send it to someone familiar with the process to flux image it with a Kryoflux or SuperCard Pro if you dont acquire one yourself.

I see. I figured that bad sectors would have been one of the easier ones to crack. Didn't realize that I needed special equipment for copy protected disk in general.

7 minutes ago, Nezgar said:

Actually, having written all that I just checked a recent list of "verified" software in the Atari 8-Bit preservation initiave, and the Gorf disk is on the list.

Good to know! The disk version has features that the cartridge version lacks. Such as high score saves and the ability to natively run on Atari XL/XE hardware without a translator disk.

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13 minutes ago, The Mr. Video said:

I see. I figured that bad sectors would have been one of the easier ones to crack. Didn't realize that I needed special equipment for copy protected disk in general.

Good to know! The disk version has features that the cartridge version lacks. Such as high score saves and the ability to natively run on Atari XL/XE hardware without a translator disk.

Disks with only bad sectors may be easier to crack -- assuming it just has bad sectors and not also duplicate or something else.  

 

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1 hour ago, The Mr. Video said:

I figured that bad sectors would have been one of the easier ones to crack. Didn't realize that I needed special equipment for copy protected disk in general.

Stock Atari drives have no interface to send any custom code to the drives, with basically only simple read/write sector and format whole disk commands. Early copy protection schemes that used only certain types of bad sector protections could be 'recreated' by writing specific sectors with a too-slow RPM. One low tech method I've heard of was to attach a piece of tape to the disk so as to stick out of the drive - and then pull on it to cause extra friction on the disk to slow it down during the write. A bit of trial and error would yield errors reading the sector.

 

Other protections require mods with at least a custom ROM to allow more direct control over the disk controller.

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Yeah, hardware copy only on this one. Full of duplicate sectors.

 

Gorf (1982)(Roklan)(US) - T0 - CRC s5, Duplicate s17 x2, T1-38 - Duplicate s17 x2

 

Gorf.thumb.jpg.f7e2fb535bd0f54435469fd6b53c4dc9.jpg

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Stock Atari drives can't duplicate such copy protection.  That's why the likes of Happy Boards exist.

Generally you'd backup by using a copier that copies the disk disregarding any filing system and just copies sectors at a time into a memory resident buffer.

The usual is for bad reads that it does 1 or 2 retries.

Detecting things like duplicate or missing sectors can be hard because the drive firmware just has generic errors and the status command doesn't give much info either.

One way to detect dups is to read the same sector multiple times but for an entire disk can take a long time, plus I don't know if any software exists to do it on a standard drive.

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6 hours ago, Rybags said:

One way to detect dups is to read the same sector multiple times but for an entire disk can take a long time, plus I don't know if any software exists to do it on a standard drive.

I believe this is how the APE ProSystem works to detect duplicate/phantom/weak sectors with a stock drive, and otherwise just noting which errors the drive returns on other problematic sectors for later 'replay' in an emulator... (reading each sector multiple times) I haven't used it myself, but I recall mention of it indeed taking longer if you know you are trying to back up a protected disk...

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