What happened to DVD writing?

[Richard Mahlerwein]

>From: Zaphod Beeblebrox <zbeeble at gmail.com>
>Subject: Re: What happened to DVD writing?
>To: mahlerrd at yahoo.com
>Cc: stable at freebsd.org
>Date: Sunday, September 20, 2009, 9:12 PM
>
>On Sun, Sep 20, 2009 at 4:35 PM, Richard Mahlerwein <mahlerrd at yahoo.com>wrote:
>
>>
>> I have had several exhibit behavior even more odd.
>>
>> The most unusual was this particular CD writer... It read both DVDs and CDs
>> but would write neither (it had worked fine the week before).  I took it out
>> of the drive bay and hooked it to another PC to test and it worked fine
>> there.  I put it back in the original PC and it failed.  I was swapping
>> things around on that PC (assuming bad cable, bad power, etc) and had it
>> sitting loose on the desk and found that it now worked again.  Put it back
>> in the drive cage and it again would not write, though reading was fine.
>> Anyway, I finally figured out that even slight pressure in on the sides
>> where it mounts would make it fail to burn CDs.  The cage itself exerted a
>> bit of pressure and that was enough to make it fail at any attempt to burn a
>> CD.
>>
>
>This is not necessarily odd.  The CD burner is one of the highest draw bits
>in your system... save possibly your CPU and/or graphics card (depending on
>what they are).  I have found that various DVD drives have been very
>sensitive to power supply voltages and fail to burn properly when they're
>marginal.  Your description here seems to point in that direction.  If it
>works in computer B, try using B's power supply for A --- or maybe B has
>other lighter draws.

>Power supplies can also degrade over time --- especially if you have some
>cheap capacitors in there.

>I find the DVD drive is often the canary for spotting power supply problems.

Sorry, the kids woke up from naps and I sent without realizing I hadn't quite finished.

Yes, you are completely correct.  There was another story where it was a power supply that was inadequate (should have been, but it was aged and seemed to just run out of steam earlier than it used to).  

Anyway, the point I intended to make and forgot to was that in this case I'd confirm that the DVD drive itself is OK by popping it into another PC, if one is available.  If it fails in a different known-OK PC it is likely to be a hardware problem.  If it works OK there, try a different power cable on your existing PC, or try swapping out the power supply if you can.  You could also try just disconnecting any other power-hungry yet unneeded items temporarily (like additional CD/DVD readers/writers or that old 6x 9GB drive SCSI2 RAID array :), if you have any.