[comp.sys.amiga.tech] Copy Protection Schemes

ksp@anuck.UUCP (p.s.kasten) (01/23/89)

I hope this doesn't start a discussion of the pros and cons of copy
protection.  All I'm looking for is some info...

How do these schemes work?  If the AMIGA can read a RAW track and write a
RAW track, how does the copy become different from the original?  Especially
if the track is read in synchronized with the Index Sync, not with the Sync
Word (which can be modified). 

---------------------------------------------------------------------------
My opinions and questions are my own; my long distance company and employer
are AT&T.

phil kasten
...!att!mvuxj!ksp
---------------------------------------------------------------------------

rap@ardent.UUCP (Rob Peck) (01/26/89)

In article <1411@anuck.UUCP>, ksp@anuck.UUCP (p.s.kasten) writes:
> I hope this doesn't start a discussion of the pros and cons of copy
> protection.  All I'm looking for is some info...
> 
> How do these schemes work?  If the AMIGA can read a RAW track and write a
> RAW track, how does the copy become different from the original?  Especially

The one copy protection scheme that I don't believe can be broken for a
standard Amiga to be used as a raw track copier is based on the syncing
ability of the Paula chip (I believe this is the correct one...).  The
disk read circuitry can synchronize to a faster bit rate than, under
actual clock control, it can write.  Thus if the standard number of
sectors on a track is 11, as I recall by writing the disk on a special
machine with a faster bit rate than the Amiga, one could squeeze 12
sectors, formatted normally so to speak, on the same track.  The Amiga
could sync to this higher rate, but using a standard clock, like "Joe Breaker"
has in his machine, it would be possible to READ this data, but not
enough room on the disk to WRITE it out again for the copy in a single
revolution.  Thus unless the program code was hacked as well, this
would make it a lot harder to break and impossible on a standard
machine to copy.  (My exposure to Amy hardware is over 2 years old,
so I might not be correct, but this is something I recall from some
time past).

I don't know about any other schemes, but this one always impressed me
as pretty good.

Rob Peck

wtm@neoucom.UUCP (Bill Mayhew) (01/27/89)

You can make backup copies of your favorite disks that were written
with a speeded up clock by slowing down the disk rotational speed
on "Joe Breaker's" machine.  I did such on mine to copy some 
nasty disks.  I have an old Amiga 1000 with NEC disk drives.  On
the bottom of said drives there is a pot to control the spindle
RPM.  Some other drives, Panasonic for instance, seem to use a
crystal controlled time base for the motor, and can not be tweaked
to copy nasty disks.

The solution is to make the software good enough that people would
rather buy a genuine copy rather than pirate something of possibly
unknown origin.  The virus scare actually works to your benefit to
encourage people to buy orginals.  We'll ignore the small number
of commercial relases came with a virus at no additional cost :-).

--Bill

karl@sugar.uu.net (Karl Lehenbauer) (01/28/89)

In article <1482@neoucom.UUCP>, wtm@neoucom.UUCP (Bill Mayhew) writes:
> The solution is to make the software good enough that people would
> rather buy a genuine copy rather than pirate something of possibly
> unknown origin.

If it's easy to pirate and a person is not aversive to doing so, why
would they be less likely to pirate a good program than a bad one?
-- 
-- uunet!sugar!karl  | "We've been following your progress with considerable 
-- karl@sugar.uu.net |  interest, not to say contempt."  -- Zaphod Beeblebrox IV
-- Usenet BBS (713) 438-5018