Why do optical discs sometimes run hot?

[JP]

Just by way of interest -

Why do optical discs - DVDs, audio and data CDs... - sometimes run so warm
(even hot)? I can understand the drive mechanism warming up from a high
speed date access/write session, but the discs do not rub against anything.
So why do they warm up?

I have noticed this very often (not always). I could not correlate this
phenomenon to drive unit, access (UDMA or PIO), read speed or particular
computer overall specs. I also understand that discs being written to would
get warm because the data is literally burnt on to it. But reading it?

Any insights would be warmly received.

Regards and thanks.



JP
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[RJK]

Well, they do have lasers in them !

regards, Richard

 

[JS]

A CD/DVD-RW unit can consume as much as 20 to 25 watts when in use!

JS