Amiga ISO Collection/AmigaUtilCD1.iso/Disk&HD/CLE-DPT2.LHA/DiskProtector/DiskProtector2.readme

Text File | 1994-10-04 | 7.5 KB | 179 lines

Peter van Campen's Disk Protector 2  29-9-94

This util puts a copy-protection on any disk you like.
Use it on "NO-DOS" disks for optimal effect.
The disk is protected against al hardware-copiers & nibblers.
There is no error-track on disk. Just try it out, it's great.
Be careful with this ! Only spread it to good contacts...

Signed: Peter van Campen (RattleHead), Tuinstraat 17
        1944 VT Beverwijk, The Netherlands.
[e-mail]

LEFT-MOUSE: Protect disk in DF0:     RIGHT-MOUSE: Quit

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15 april 1991 I wrote Disk Protector v1.0, with the making of
a copy protection for RattleCopy I got the knowledge to do this.
It got spread very well and I got letters like:

"Dear Rattle, I buy pirated games for $5 dollar from somebody
in my town but I can't copy them because of your Protector.
Can I get a deprotector for it ?"

I didn't make the program with some masterplan at the time, I
did it because I thought it was a funny trick.

Some time later Kickstart v2.0 came out and I found out that
it didn't work on it.

I wasn't the only one, I got a load of letters from guys who
made a lot of money selling reprotected disks to local kids.
They begged for an update and offered amounts like $100 dollars
for this update.

At that time, and until recently, I hated these criminals and
I never made an update.

About 6 months ago I red a plan of some pirate to stop selling
pirate-disks to local kids and keep them in the scene. The scene
is about 10% of the total Amiga market. The idea was that those
kids (90%) whould buy the games and the Amiga market whould
grow again. I thought it was a nice idea to try, and forgot it.

Some days ago, I started to write to another programmer, he
wanted to make a diskprotection utility, he probably never heard
of DiskProtector and we chatted along like this:

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Message 1:

 Him> and he knows someone in some company
 Him> and wants a program to read the bootblock write it to

I also got 2 letters from a guy in the oil-region (bahgrein ?) and he
asked the same thing, I wrote "Diskprotector" once, an utility that
copyprotected normal amiga-dos disks, but it didn't work on kick v2.0.
He offered me money and stuff but I decided not to do it, I quit the
pirate-scene, they're all selfish criminals who think they're cool
'cause they can crack a little, pathetic.
The guy is probably a local spreader who wants to earn big money by
selling re-protected warez, and when you make that program, you help
the killing of Amiga. Do you want that ? I guess not,

 Mcc> Also you said something about the RattleCopy protection?
 Mcc> I'd love to how it was implemented (to work) and what it did..

Diskdrive motors are mechanical, so they have little speederrors.
One drivemotor can be a little faster than another drivemotor.
When data is written, the drive uses a timerpulse.
The average number of bytes is $3200 on a track, when the drivemotor
is faster, this becomes lower, like $3100, when the drive is slower,
this becomes higher, like $3300.
When data is red, the drive uses the bitsize on the disk as pulse,
that's the reason why MFM-coding is used. It changes the data to
as much different bits as possible. Data like 000011110001111111000
is changed to 110100110010100101, so it's easier for the drive to
get the correct pulse. (bit-example is made up, not correct)

Protection trick: when I write tracks on my drive, they are always
the same length, give or take 2 bytes, 'cause of the speed of my
drive. Let's say it's $3268.
I wrote RattleCopy v2.2 in strange-format tracks, after I did this
I checked all track-lenghts, and put them in the boot-track.
Example: $3268,$3268,$326a,$3266,$3268 etcetra.
When the program is loaded, these lengths are checked.
When somebody gets this disk, and COPIES it, the lengths will be
different due to the speed of his drive. Like $3286.
This trick even fools hardware-copiers, it is also used in
commercial game protections but they use margins like $3260-$3280
'cause they have to copy a lot of disks on different hardware, this
kills the trick a bit because a lot of drives are in this region.
It's a cool trick for hobby-coders products.

(To technicians: this is the way I understand it, some things may
be wrong)

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Message 2:

 Him> but the program is going to
 Him> be useless anyway as anyone can copy track 81 with xcopy, and
 Him> will probably try when doscopy doesn't work.

And now the big solution: (drums !)

We know that drivemotors have different speeds, so when we write
data to a disk, we need some overlap-data in the data we write.
The true data is $2f00 bytes, we add overlap-space (empty data)
of $400 bytes, making $3300 bytes of data.
This overlap-space is called "The gap".
You write $3300 bytes of data to the disk, the Gap first ($400 and
$2f00 in that order) because the end of the true data will
overwrite the Gap.

"Diskprotector" used the following trick:

About 512 bytes of the bootblock was copied in the Gap of track 0,
this could be done because the Gap of the Amiga format is big
enough. (RattleCopy does the same thing with the RattleMap)
The 512 bytes of the bootblock was replaced by the
protection-routine, it also did the tracklength-check trick.
This resulted in a normal-formatted LOOKING disk, because Amigados
ignored the stuff in the Gap.
It couldn't be copied because (hardware) nibblers got tricked by
the track-length counter, normal doscopiers didn't copy the gap,
so copies would guru.
This also solves the problem that some drives can't copy track
80-81.

(I'm not having an ego-trip, I just love hacks like this.)

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After these messages I started thinking: Disk Protector could make
the plan of stopping-local-spreading work. It did in 1991 in a
big way, I got letters even this year complaining about the bug.
Ofcourse somebody will make a deprotector again, a friend of mine
made one back in 1991, after I told him he couldn't do it. :-)
But that deprotector was never spread in a big way, I think the
local pirates stopped it to prevent it to go to the local kids.

So here it is, Disk Protector 2, it is tested on Kickstart 1.3, 2.0
and 3.0. I lost the sources, so I had to debug it with changing
things in the executable file. :-)

Why I write so much text ? I want a lot of people to use it, so
we can see if it will help the selling of Amiga software.
This will mostly be games, because the trick only works well
on no-dos disks, so mostly cracked games that only can be
started with bootblock-loading. These games are also the most
copied software.

IMPORTANT When you try this program, remember:

When you nibble-copy the protected disk, and you write to the SAME
drive that is used to PROTECT the disk, the chance is high that
the copy works, the trick is that it can't be copied with
ANOTHER drive, due to the speed of the drivemotors !!!
Copy it to another drive, or to a friends drive to see that it
really works.

Disclaimer:
I'm not responsible for the destruction of any data due to the use
of this program.
This program is ment to prevent piracy, not making pirates richer.

 (I hope it sounds important enough)

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