Mailinglist Archive: opensuse (3336 mails)

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Funky DVD / Drive Behavior
  • From: Randall R Schulz <rschulz@xxxxxxxxx>
  • Date: Wed, 30 Nov 2005 20:16:14 -0800
  • Message-id: <200511302016.14895.rschulz@xxxxxxxxx>

Recently I began to have trouble with YaST refusing to use the SuSE 10.0
commercial DVD for new package installations. It claimed there wasn't a
distribution on the device, though clearly there was, as I'd installed
from it many times already. Examining it via the shell seemed to show
everything being in order, but when I went to look
at .../media.1/media, I got this:

% cat /media/SU1000_001/media.1/media
cat: /media/SU1000_001/media.1/media: Input/output error

Since I have two DVD recorders in this system, I switched to the other
one and when using that drive, everything's working fine. YaST will
install from that drive and cat shows the expected contents of
the .../media.1/media file.

Experimenting further, I tried these commands:

% dd if=/dev/hda of=/dev/null bs=4096
1048575+1 records in
1048575+1 records out
4294965248 bytes (4.3 GB) copied, 534.002 seconds, 8.0 MB/s

% dd if=/dev/hdc of=/dev/null bs=4096
2082936+0 records in
2082936+0 records out
8531705856 bytes (8.5 GB) copied, 1089.81 seconds, 7.8 MB/s

/dev/hda is the misbehaving drive and /dev/hdc is the one that works.

Hda is a Sony DRU-720A dual-layer writer, hdc is an older Sony DRU-510A
single-layer writer (both are capable of reading dual-layer media).
Both are IDE drives configured as masters of the two separate IDE buses
of my mainboard. There are no slaves on those buses and all other mass
storage is on SCSI.

It seems very odd that while no error was reported, reading stopped on
hda after 4.3 GB while hdc when the full 8.5 GB. One might suppose that
hda couldn't handle the layer switch yet reported no error when it
should have done so.

Another oddity I noticed when conducting these experiments was high CPU
usage when accessing hda. It turns out its DMA had gotten turned off
somehow. I reenabled it and ran the test again. Aside from going about
twice as fast, nothing changed.

Has anybody seen symptoms like this? Can you shed any light on what
might have happened to the malfunctioning drive to account for these
peculiar symptoms?


Randall Schulz

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