Date   : Sun, 11 Feb 1990 04:50:27 GMT
From   : titanic.cs.wisc.edu!tonyrich@speedy.wisc.edu (Anthony Rich)
Subject: MOVCPM has copy protection

In article <1534@shell.shell.com> svh@shell () writes:

>I have recently gotten together an 820-I with 8" drives, and would like to
>do some stuff that would require me to MOVCPM down a couple'o K. The
>problem is, that the version I have will generate "Synchronization error"
>every time.

I ran into the "Synchronization error" message recently, too.

According to the book "Inside CP/M" by David E. Cortesi, MOVCPM has a kind
of copy protection built into it.  When it starts up, it does some
checking to see whether the copy of CP/M you're trying to generate with
MOVCPM matches the copy of CP/M you're currently running.  If not, it
displays the message "Synchronization error" and quits.  (I'm not sure
what it actually tries to match.  I think it does some kind of checksum.)

As a result, you can't run MOVCPM to generate a new copy of your CP/M
while running someone else's copy of CP/M.

I wanted to do exactly that for a legitimate reason.  My CP/M disk won't boot
because I replaced my broken 8" DSDD drive with a different manufacturer's
that had different seek characteristics, so I needed to generate a newly
configured version of CP/M to handle the new drive.  Of course, to do that,
I have to already be booted up on the new drive and running with SOMETHING,
so to get me started, a net person graciously sent me a bootable CP/M disk
that allows me to boot and read 8" SSSD diskettes on my new drive.  But I
can't use it to generate a properly configured version of MY OWN, PAID-FOR,
LICENSED COPY of CP/M because of that $*!!#@@! "copy protection" in MOVCPM!
Grrr!

If anyone has or can invent a workaround for the "Synchro error" copy
protection, I'd appreciate being informed so I can get my CP/M reconfigured
and booting happily again on my new drive.  Apparently the copy protection
is smart enough that you can't simply step over it using DEBUG.

  Tony
--
Email:       tonyrich@titanic.cs.wisc.edu  Phone:  608-271-8450
Disclaimer:  The opinions above are mine.  Others may agree or disagree.