[conspire] cd burning giving slight errors

Fri Oct 5 09:22:12 PDT 2012

On Thu, Oct 4, 2012 at 5:49 AM, Rick Moen <rick at linuxmafia.com> wrote:
> Quoting Peter Knaggs (peter.knaggs at gmail.com):
>
>> I eventually tracked the problem down to a bad memory slot
>> on the motherboard itself.  Apparently that one slot isn't capable
>> of running at full speed, no matter what memory stick I put
>> into it.  Short of getting the manufacturer (ASUS)
>> to replace the motherboard (It's still under warranty, it's
>> a P7P55LX), I've found that running the entire
>> memory bus at a slightly lower frequency setting
>> (800MHz instead of 1333MHz) solved the trouble
>> of reading and writing CDs. It's curious that memtest86
>> doesn't show any troubles, and parallel linux kernel builds
>> went through fine: it was only I/O to the CD drives that
>> was affected by this "bad memory slot" issue, the symptom
>> being I/O errors when higher speed reading or writing was used.
>
> That's pretty subtle, all right.
>
> I'm going to make a silly wild-assed guess that the difference between
> the memory activity exploited by memtest86 and the memory activity
> exploited by CD-reading somehow involves motherboard circuitry used for
> DMA in the latter case but not the former.
>
> As a reminder, I just don't have as much faith in memtest86 or any of
> its immediate kin as I do in massively parallel (make -j) iterative
> kernel compiles, as discussed in the conspire thread linked from my
> http://linuxmafia.com/~rick/ personal page (concerning 'the best way to
> test RAM', or words to that effect).

Hi Rick,

The curious thing is that at the time I'd remembered your
thread about using parallel kernel compiles and for this
motherboard issue it didn't have any trouble completing
them all clean with no errors. So maybe we need to add
"reading CDs at high speed" to the battery of memory tests,
as crazy as that sounds, maybe a bootable CD "system
stress-tester" that sha256sums its own image over and over,
while merrily kicking off parallel kernel compiles, heh!

> I remember a really subtle motherboard problem back in late 386 days.
> I bought an offbrand motherboard with an AMD 386/40, which was great
> with OSes du jour until I upgraded it from (if memory serves) OS/2 3.0
> Warp instead of OS/2 2.1, whereupon it suddenly had major stability
> issues that went away if I either disabled CPU caching (ick!) or stepped
> down the system clock from 40 to 16 MHz (ick!), whereupon it was fine.
>
> Eventually I figured out the cause for this wacky problem:  The OEM had
> taken a motherboard that was in-spec for an Intel 386/33 chip and just
> crammed an AMD 386/40 into it for higher speed appeal and slightly more
> retail margin.  (They jobbed off the removed Intel chip separately, or
> it didn't have one.)  Result was a motherboard that was just slightly
> out of spec on the northbridge, leading to subtle timing problems with
> some OSes but not others.
>
> I junked the motherboard and made tried to avoid similar errors
> involving hidden hardware weaknesses.

I was wondering have you encountered any troubles with
I/O to flash memory (specifically the 32GB "MicroSDHC" variety from SanDisk,
that comes with a little "adapter sdcard" so that you can plug it in).
I've found that older varieties (16GB MicroSDHC) cards work
fine (reading at around 18MB/s according to "dd"), but the newer
ones give tons of errors during writing, no troubles reading
(this is with the 3.2.0-29-generic kernel),
but work fine with writing in Apple OSX 10.6.8  (pretty old at this point).

Writing works fine for a while

[299034.228302] sdb: detected capacity change from 31914983424 to 0
[299067.421319] sd 6:0:0:0: [sdb] 62333952 512-byte logical blocks:
(31.9 GB/29.7 GiB)
[299067.423018] sd 6:0:0:0: [sdb] No Caching mode page present
[299067.423026] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[299067.425741] sd 6:0:0:0: [sdb] No Caching mode page present
[299067.425749] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[299067.427167]  sdb: sdb1
[299342.617669] sd 6:0:0:0: [sdb] No Caching mode page present
[299342.617679] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[299424.890200] sd 6:0:0:0: [sdb] No Caching mode page present
[299424.890208] sd 6:0:0:0: [sdb] Assuming drive cache: write through

Then the write errors out with something like this (length of
time varies a lot, it can be 30 seconds before the error happens,
sometimes it happens in the first few seconds).

[299446.784741] sd 6:0:0:0: [sdb] Media Changed
[299446.784748] sd 6:0:0:0: [sdb]  Result: hostbyte=DID_OK
driverbyte=DRIVER_SENSE
[299446.784754] sd 6:0:0:0: [sdb]  Sense Key : Unit Attention [current]
[299446.784761] Info fld=0x0
[299446.784764] sd 6:0:0:0: [sdb]  Add. Sense: Not ready to ready
change, medium may have changed
[299446.784772] sd 6:0:0:0: [sdb] CDB: Write(10): 2a 00 02 fe 9c 60 00 00 f0 00
[299446.784785] end_request: I/O error, dev sdb, sector 50240608
[299446.796080] FAT-fs (sdb1): FAT read failed (blocknr 6324)
[299446.796104] FAT-fs (sdb1): FAT read failed (blocknr 6317)
[299446.796600] FAT-fs (sdb1): Directory bread(block 48070613) failed
[299446.796609] FAT-fs (sdb1): Directory bread(block 48070614) failed
[299446.796616] FAT-fs (sdb1): Directory bread(block 48070615) failed
[299446.796623] FAT-fs (sdb1): Directory bread(block 48070616) failed
[299446.796629] FAT-fs (sdb1): Directory bread(block 48070617) failed
[299446.796636] FAT-fs (sdb1): Directory bread(block 48070618) failed
[299446.796643] FAT-fs (sdb1): Directory bread(block 48070619) failed
[299446.796650] FAT-fs (sdb1): Directory bread(block 48070620) failed
[299446.796657] FAT-fs (sdb1): Directory bread(block 48070621) failed
[299446.796664] FAT-fs (sdb1): Directory bread(block 48070622) failed
[299446.796696] FAT-fs (sdb1): Directory bread(block 48070613) failed
[299446.796707] FAT-fs (sdb1): Directory bread(block 48070614) failed
[299446.796714] FAT-fs (sdb1): Directory bread(block 48070615) failed
[299446.796721] FAT-fs (sdb1): Directory bread(block 48070616) failed
[299446.796727] FAT-fs (sdb1): Directory bread(block 48070617) failed
[299446.796734] FAT-fs (sdb1): Directory bread(block 48070618) failed
[299446.796741] FAT-fs (sdb1): Directory bread(block 48070619) failed
[299446.796748] FAT-fs (sdb1): Directory bread(block 48070620) failed
[299446.796754] FAT-fs (sdb1): Directory bread(block 48070621) failed
[299446.796761] FAT-fs (sdb1): Directory bread(block 48070622) failed
[299446.796780] FAT-fs (sdb1): Directory bread(block 48070613) failed
[299446.796787] FAT-fs (sdb1): Directory bread(block 48070614) failed
[299446.796793] FAT-fs (sdb1): Directory bread(block 48070615) failed
[299446.796800] FAT-fs (sdb1): Directory bread(block 48070616) failed
[299446.796807] FAT-fs (sdb1): Directory bread(block 48070617) failed
[299446.796814] FAT-fs (sdb1): Directory bread(block 48070618) failed
[299446.796820] FAT-fs (sdb1): Directory bread(block 48070619) failed
[299446.796827] FAT-fs (sdb1): Directory bread(block 48070620) failed
[299446.796834] FAT-fs (sdb1): Directory bread(block 48070621) failed
[299446.796841] FAT-fs (sdb1): Directory bread(block 48070622) failed
[299446.796882] FAT-fs (sdb1): FAT read failed (blocknr 6324)
[299446.796952] FAT-fs (sdb1): Directory bread(block 48070613) failed
[299446.796959] FAT-fs (sdb1): Directory bread(block 48070614) failed
[299446.796966] FAT-fs (sdb1): Directory bread(block 48070615) failed
[299446.796972] FAT-fs (sdb1): Directory bread(block 48070616) failed
[299446.796980] FAT-fs (sdb1): Directory bread(block 48070617) failed
[299446.796987] FAT-fs (sdb1): Directory bread(block 48070618) failed
[299446.796993] FAT-fs (sdb1): Directory bread(block 48070619) failed
[299446.797000] FAT-fs (sdb1): Directory bread(block 48070620) failed
[299446.797007] FAT-fs (sdb1): Directory bread(block 48070621) failed
[299446.797014] FAT-fs (sdb1): Directory bread(block 48070622) failed
[299446.797037] FAT-fs (sdb1): Directory bread(block 48070613) failed
[299446.797044] FAT-fs (sdb1): Directory bread(block 48070614) failed
[299446.797051] FAT-fs (sdb1): Directory bread(block 48070615) failed
[299446.797057] FAT-fs (sdb1): Directory bread(block 48070616) failed
[299446.797065] FAT-fs (sdb1): Directory bread(block 48070617) failed
[299446.797071] FAT-fs (sdb1): Directory bread(block 48070618) failed
[299446.797078] FAT-fs (sdb1): Directory bread(block 48070619) failed
[299446.797085] FAT-fs (sdb1): Directory bread(block 48070620) failed
[299446.797092] FAT-fs (sdb1): Directory bread(block 48070621) failed
[299446.797099] FAT-fs (sdb1): Directory bread(block 48070622) failed
[299446.797118] FAT-fs (sdb1): Directory bread(block 48070613) failed
[299446.797124] FAT-fs (sdb1): Directory bread(block 48070614) failed
[299446.797131] FAT-fs (sdb1): Directory bread(block 48070615) failed
[299446.797138] FAT-fs (sdb1): Directory bread(block 48070616) failed
[299446.797145] FAT-fs (sdb1): Directory bread(block 48070617) failed
[299446.797152] FAT-fs (sdb1): Directory bread(block 48070618) failed
[299446.797159] FAT-fs (sdb1): Directory bread(block 48070619) failed
[299446.797166] FAT-fs (sdb1): Directory bread(block 48070620) failed
[299446.797177] FAT-fs (sdb1): Directory bread(block 48070621) failed
[299446.797184] FAT-fs (sdb1): Directory bread(block 48070622) failed
[299446.797246] FAT-fs (sdb1): FAT read failed (blocknr 6324)
[299447.286491] sd 6:0:0:0: [sdb] No Caching mode page present
[299447.286499] sd 6:0:0:0: [sdb] Assuming drive cache: write through

>
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