 |
|
| What
is Quality? |
A Quality disc is one that will work every time in
every drive, with a level of performance and
lifetime appropriate for the application |
|
| It's
Worse than you Think! |
|
Discs that
appear "Good" may not be.
Disc Quality is
hidden by powerful error correction.
|
|
|
|
CD
Testing is not just for CD manufacturers anymore. If you
are involved with the creation, duplication, replication or
distribution of CD's, you can save money and prevent problems by
being able to measure disc quality.
Why
Test CD's?
 |
Data
comparison does not measure disc quality.
|
|
Just
because you can read it doesn’t mean it’s good.
|
|
Poor
disc quality can cause unreliable operation and short lifetime.
|
All
CD's incorporate very powerful error detection and
correction. Data discs have an additional layer of error
correction as well. This error correction is extremely
effective, and CD's could not work without it, as there would be
far too many errors.
However,
the error correction also hides a multitude of sins. In
principle, it is possible to drill a 2mm hole through the disc,
and still recover every single bit! But even though this
disc is readable, you could not consider it a "good"
disc. It will be slow and unreliable. The data could
become unrecoverable at any time.
The
only way to judge the quality of the disc is to make sure it
conforms to Red Book specifications. Measuring error rates
also shows the location and severity of defects.
Who Should Test CD's?
| Duplicators
 |
Evaluate
and Qualify CD & DVD Media. |
|
Identify
burners that are failing or about to fail. |
|
Discover
if the problem is the media or the writer.
|
|
Make
sure the masters are good.
|
|
| Replicators
| Quality
Assurance |
| Production
line screening |
| Conformance
with License Agreement
|
|
| Distributors
| Manage
quality variations from suppliers. |
| Generate
confidence in products.
|
| Avoid
returns & unhappy customers.
|
| Get
what you pay for.
|
|
| Mastering Studios
| Make sure your pre-masters can be
mastered. |
|
| End
Users
| Avoid
long access times.
|
| Increased
reliability for critical applications.
|
| Archiving
- High quality discs have longer lifetime.
|
|
|
|
|
Qualify
Your Media
|
|
The key to
CD & DVD duplication success is compatibility between
the media and writer. You can find out which
type and brand of media works best with your
writers by using our products.
|
|
| Keys
to Reliability |
|
The key to
disc reliability is "pit
geometry". The player's ability to read
the disc is wholly dependent on the size and shape
of the pits. |
|
| How
Good is "Good Enough"? |
|
All CD's and DVD's must meet Red Book or DVD Forum
specifications.
Beyond that, you must decide how high your quality
standards should be based on how critical your
application is. Applications where the cost
of failure is high need higher standards of
quality. |
|
|
 |
