Re: [ARSCLIST] CD writing speed - long reply

[Mike Richter <mrichter@xxxxxxx>]

Jos Van Dyck wrote:
> Tom Fine wrote:
>
> > I use Plextor dirves and have them set to use the fastest optimum speed. 
>
> How do you know the "optimum speed" for a given media and drive?
>
> Jos
It is *extremely* tempting to respond with sarcasm, but I shall resist it.

The optimum speed is usually taken to be that at which the error rate is 
lowest. Under some circumstances, one may prefer to operate near the 
optimum rather than at it - for example when one can use a higher speed 
with little increase in error rate but substantial saving of time. Let 
us look, then, at "optimum" as being the speed at which the recording 
has the fewest errors.

To determine what conditions create such an optimum, one must measure 
error rate. Professional gear for that purpose is costly and requires 
great skill to use properly. If you have had a disc evaluated at Media 
Sciences, you know that substantial skill is needed even to understand 
their assessment. An institution with sufficient interest in archiving 
may well invest in an expert to assess detailed reports and to manage 
ongoing recording. Fortunately, the rest of us have a simpler answer: 
assess a composite index rather than the array of components.

To that end, there are many tools available which operate in a 
conventional drive (thorough testing requires modified hardware) and 
report understandable information. Because of the intense error 
correction required for optical media, a simple pass/fail measurement is 
of little value. Much more interesting is the number of retries - error 
corrections - required to read the disc.

I have long preferred the CD and DVD Inspector and Diagnostic programs 
now published by Infinadyne for this job, but for CDs one can use the 
quality measurement of CDSpeed (now part of Ahead's Nero suite) to much 
the same effect. There may be others as well - one hopes there is 
something for other platforms than Windows - but I've not tried with them.

I have been at this optical recording business for over a decade but 
have yet to understand the mindset of so many users. The thought of 
measuring error rate to determine how well one writes a disc seems 
foreign to many otherwise rational recordists, even to those with 
scientific orientation. Perhaps it is only a misplaced belief in the 
infallibility of digital processes.

Mike
--
mrichter@xxxxxxx
http://www.mrichter.com/