SCSI CD burner

[John Foust]

At 02:35 PM 9/16/2006, CRC wrote:
>The basic problem with commercial CD burners/players is that they  
>keep the laser diodes on when powered, although at the low power  
>required for reading. The life of run-of-the-mill laser diodes is on  
>the order of 10,000 (10.000) hours. Consequently, if you keep your  
>system on all the time you can expect one to two years of useful life  
>from the beast (some longer, some shorter).  From <http://www.wtec.org/ loyola/opto/ad_rohm.htm>:

That document dates from 1994.  You'd think that manufacturers would
want to increase MTBF and eliminate failures as quickly as possible,
so I find it hard to believe that LEDs are left on inside today's
CD/DVDs just because it's hard to turn them off and they don't want
to improve lifetimes.  This info may be entirely relevant for 
1980s drives, who knows?  What sorts of other ancedotes and
claimed facts do we have?

 From the CD-R FAQ: http://www.cdrfaq.org/faq05.html

Subject: [5-2] How long do CD recorders last? (1998/04/06)

  The MTBF (Mean Time Between Failures) on these drives is typically 50,000 
  to 100,000 hours, and they come with a 1 year warranty. Compare that to 
  hard drives rated at between 500,000 and 1,000,000 hours with a 3 or 5 
  year warranty and that should give you some idea. Most of the drives 
  available today weren't meant for mass production of CD-Rs. The only 
  exceptions are the venerable Philips CDD 522, Kodak PCD 600, and Sony CDW-900E. 

By 2004, MTBF for consumer CD/DVD were up to 60K to 100K hours:

http://www.computingondemand.com/reviews/storage-LiteOn-LDW-411S/page1.shtml

And perhaps their MTBF was calculated with a 2% duty cycle, which 
would still mean they expect a consumer DVD-R to be able to burn
several thousand discs.  I suspect consumer losses are due more to
dust and crud on discs...  unless of course you simply don't want to
trust manufacturer-provided MTBFs.

Your average $50 Wal-Mart DVD drive has a 70K MTBF:

http://www.liteon.com/prod/getProduct.do?cid=1_7_13&xml_id=4_2&menu_id=4_2_7

- John