我的系统在读取不完美的 CD-R/DVD-R（驱动器读取速度慢）时会不时挂起。这就像文件系统的 IO 滞后一样，每当应用程序想要读取或写入某些内容时，它都会“挂起”几秒钟。当支持完美（驱动器旋转速度快）时，问题就不存在了。
是否有一些调整可以防止这种烦人的行为，或者这纯粹与硬件有关？我不记得使用较旧的 IDE 材料时出现过此类问题...它是 plextor sata CD/DVD 刻录机。以下是一些系统信息。
nicolas@nicolas-ad21:~$ dmesg | grep sd
[ 1.717049] sd 0:0:0:0: Attached scsi g
eneric sg0 type 0
[ 1.717077] sd 0:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/931 GiB)
[ 1.717886] sd 0:0:0:0: [sda] Write Protect is off
[ 1.717888] sd 0:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 1.719880] sd 0:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 1.742304] sda: sda1 sda2 sda3
[ 1.743164] sd 0:0:0:0: [sda] Attached SCSI disk
[ 2.397358] sd 1:0:1:0: Attached scsi generic sg2 type 0
[ 2.397399] sd 1:0:1:0: [sdb] 390719855 512-byte logical blocks: (200 GB/186 GiB)
[ 2.397641] sd 1:0:1:0: [sdb] Write Protect is off
[ 2.397644] sd 1:0:1:0: [sdb] Mode Sense: 00 3a 00 00
[ 2.397764] sd 1:0:1:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 2.409299] sdb: sdb1
[ 2.409729] sd 1:0:1:0: [sdb] Attached SCSI disk
[ 2.819527] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[ 13.019456] Adding 16779888k swap on /dev/sda2. Priority:-1 extents:1 across:16779888k FS
[ 15.941584] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
[ 16.171196] EXT4-fs (sda3): mounted filesystem with ordered data mode. Opts: (null)
[ 17.110190] Installing knfsd (copyright (C) 1996 [email protected]).
[ 47.756673] type=1400 audit(1420184351.112:75): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/sbin/cupsd" pid=2232 comm="apparmor_parser"
[ 47.756912] type=1400 audit(1420184351.112:76): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/sbin/cupsd" pid=2232 comm="apparmor_parser"
[ 1175.944841] type=1400 audit(1420185477.652:78): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/sbin/cupsd" pid=2654 comm="apparmor_parser"
[ 1175.945116] type=1400 audit(1420185477.652:79): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="/usr/sbin/cupsd" pid=2654 comm="apparmor_parser"
[15713.652746] sd 4:0:0:0: Attached scsi generic sg3 type 0
[15713.653242] sd 4:0:0:0: [sdc] 1250263728 512-byte logical blocks: (640 GB/596 GiB)
[15713.654530] sd 4:0:0:0: [sdc] Write Protect is off
[15713.654533] sd 4:0:0:0: [sdc] Mode Sense: 21 00 00 00
[15713.655632] sd 4:0:0:0: [sdc] No Caching mode page found
[15713.655635] sd 4:0:0:0: [sdc] Assuming drive cache: write through
[15713.658389] sd 4:0:0:0: [sdc] No Caching mode page found
[15713.658392] sd 4:0:0:0: [sdc] Assuming drive cache: write through
[15713.681978] sdc: sdc1
[15713.715017] sd 4:0:0:0: [sdc] No Caching mode page found
[15713.715023] sd 4:0:0:0: [sdc] Assuming drive cache: write through
[15713.715027] sd 4:0:0:0: [sdc] Attached SCSI disk
谢谢您对此提供的任何线索。
答案1
你经历的确实是几乎坏了CD/DVD仍然被阅读（尽管有很大的困难）。
解决方案很简单：将 CD/DVD 复制到新磁盘，问题就消失！
尽快这样做，从最糟糕的情况开始，因为继续做你正在做的事情，最终会导致磁盘的透明层上出现更多的划痕（在你的情况下可能半透明层），最终磁盘将停止读取永远。