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Re: CDs, was DATs, Was Re: arsclist Duplicating casette tapes

From: Patent Tactics, George Brock-Nannestad

Mike Richter wrote:

> Note that as Jerry has pointed out, BLER is not a sufficient measure
> of quality. However, it may be adequate for purposes such as
> identifying the faulty disc in an archived pair.

----- the usefulness of BLER in this context is that its increase over 
time (cleaned of inter-apparatus variability!) will indicate the 
progress of decay. If it does not increase, there is no need to 
recopy yet. Do not make a BLER determination based on just one 
run, but average e.g. three consecutive runs and repeat after a 
month. If there is no change, repeat after two months. Still no 
change, repeat after 6 months, and if you are lucky you may go 
annual. Once an increase is noted reduce the time interval again. 
For a large collection you will need a log file and staff.

The expensive testers are able to test the media before recording, 
but the cheap (but time-consuming) BLER test needs a recording, 
the erroneous reading of which activates the error correction. The 
output signal is perfect up to the time where non-correctible errors 

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