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Re: EDD 4 Plus Copy Kit Sold -- Report?

sicklittlemonkey wrote:

On Mar 16, 11:28 am, rhohler <rick.hoh...@gmail.com> wrote:


You made me think of a question.  Does the fact that these copy
protected disks are 20+ years old make them harder to copy or more
fragile to read?



Before Michael jumps in and says "No" ;-) I've got several old
protected disks that don't work reliably any more because the
protection fails in just one place. Obviously DOS disks are more
tolerant of certain kinds of failure, and certainly easier to recover.


OK, Nick--I waited for you before jumping in.  ;-)

Many protection schemes were based on changes to delimiting nibbles
and timing that rendered the format less reliable than the standard
format.  Many people suspected that copy-protection was achieved at
the cost of disk subsystem reliability, and they were correct.

So-called "nibble counts"--many of which are actually tricky track
signature check--are among the least completely tested, and therefore
least reliable copy-protection schemes.  They were usually tested on
a few drives by the designer, and then pushed into production.

However, they were "reliable enough" when drives were relatively clean,
had correct, stable speed, and could seek accurately.

All of these parameters are subject to degradation over time unless
preventive maintenance is current.  Dirty heads, hardening lubricants,
"stiff" belt drives, and drifting electronics are all contributing
causes to the eventual failure of "aggressive" uses of a drive, as
some of these copy-protection features certainly are.

In any case, the reliability issues are not so much the copy-protected
*media*, but the accumulated problems with the *drive(s)*.

Deprotection is still the tried-and-true method for archiving any
protected disk, and is one of the most rewarding things you can
do with an Apple II.  ;-)  Of course, there's always the "so many
disks, so little time" problem...


Whatever the cause, this is another reason why I'm putting what little
free time I have into researching a new way to make archival images.


I wish you well...

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."