Polossatik
I reject your reality and substitute my own
some idea of what is used:/dev/mmcblk0p1 is a 4gb class 6 Sd card "traveller" brand (local cheaper brand),
openpandora:/media$ sudo dd if=/dev/mmcblk0 of=/dev/null
7839744+0 records in
7839744+0 records out
4013948928 bytes (4.0 GB) copied, 233.515 s, 17.2 MB/s
now let stress the system a bit - bzip2 will use about 90% cpu
openpandora:/media$ sudo dd if=/dev/mmcblk0 |bzip2 >/dev/null
Password:
dd: reading `/dev/mmcblk0': Input/output error
57192+0 records in
57192+0 records out
29282304 bytes (29 MB) copied, 71.6724 s, 409 kB/s
same when dumping to a USB stick
openpandora:/media$ sudo dd if=/dev/mmcblk0 |bzip2 >/media/8GB_SD3/disk.dd.gz2
Password:
dd: reading `/dev/mmcblk0': Input/output error
57192+0 records in
57192+0 records out
29282304 bytes (29 MB) copied, 73.7727 s, 397 kB/s
then I tested a exact copy (same brand /model/size ) of the failing card and it also fails, but after a other amount of data:
openpandora:/media$ sudo dd if=/dev/mmcblk0 |bzip2 >/dev/null
Password:
dd: reading `/dev/mmcblk0': Input/output error
377696+0 records in
377696+0 records out
193380352 bytes (193 MB) copied, 582.049 s, 332 kB/s
It looks to me there
* is clearly a problem when reading from at least SOME Sd card's under high cpu
* it looks like card related on where it fails
it's worth noting that I tested both cards using H2testw on windows and using DD on a Ubuntu laptop , and on both systems NO fault was found.
I have other (bigger and other brands) SD cards who I let run for like a minute or 20 , but seen this is so slow I did not let them complete all the way, so I cannot be 100% sure they actually do not fail.
now I'm testing the first card again (who failed) but using the same USB cardreader as I used on my other PC's but then connected to the pandora
so far no problem found , I'll leave this test going until the whole card is dumped, but seen this is a very slow process it might take a while
I'll edit the post if it's done.
edit: this worked without any problems
openpandora:/media$ sudo dd if=/dev/sda |bzip2 >/dev/null
7839744+0 records in
7839744+0 records out
4013948928 bytes (4.0 GB) copied, 6230.45 s, 644 kB/s
The reason why I did this is because on that 4gb card I have put a copy of the Pandora distro and had sometimes bizarre issues.
Who looked quite random and I/O related .
I know there will be reply's like "buy a other/decent Sd card" , but the point is that at least the pandora is much more "picky" about Sd cards than other systems.
I use those cards already some time on my N800 for example and there I never had any issue that looked like SD card related.
If some people would sacrifice some CPU time on their Pandora doing the same ( sudo dd if=/dev/mmcblk0 |bzip2 >/dev/null or sudo dd if=/dev/mmcblk1 |bzip2 >/dev/null )
to test their cards then that would be very good to see if other people have the same issue.
at the very least it might help to establish if it's only a rare/specific to certain cards occurrence or not.
If someone would have any idea of what more diagnostic info to provide , or has other idea on how to test these cards faster, please let me know.
openpandora:/media$ sudo dd if=/dev/mmcblk0 of=/dev/null
7839744+0 records in
7839744+0 records out
4013948928 bytes (4.0 GB) copied, 233.515 s, 17.2 MB/s
now let stress the system a bit - bzip2 will use about 90% cpu
openpandora:/media$ sudo dd if=/dev/mmcblk0 |bzip2 >/dev/null
Password:
dd: reading `/dev/mmcblk0': Input/output error
57192+0 records in
57192+0 records out
29282304 bytes (29 MB) copied, 71.6724 s, 409 kB/s
same when dumping to a USB stick
openpandora:/media$ sudo dd if=/dev/mmcblk0 |bzip2 >/media/8GB_SD3/disk.dd.gz2
Password:
dd: reading `/dev/mmcblk0': Input/output error
57192+0 records in
57192+0 records out
29282304 bytes (29 MB) copied, 73.7727 s, 397 kB/s
then I tested a exact copy (same brand /model/size ) of the failing card and it also fails, but after a other amount of data:
openpandora:/media$ sudo dd if=/dev/mmcblk0 |bzip2 >/dev/null
Password:
dd: reading `/dev/mmcblk0': Input/output error
377696+0 records in
377696+0 records out
193380352 bytes (193 MB) copied, 582.049 s, 332 kB/s
It looks to me there
* is clearly a problem when reading from at least SOME Sd card's under high cpu
* it looks like card related on where it fails
it's worth noting that I tested both cards using H2testw on windows and using DD on a Ubuntu laptop , and on both systems NO fault was found.
I have other (bigger and other brands) SD cards who I let run for like a minute or 20 , but seen this is so slow I did not let them complete all the way, so I cannot be 100% sure they actually do not fail.
now I'm testing the first card again (who failed) but using the same USB cardreader as I used on my other PC's but then connected to the pandora
so far no problem found , I'll leave this test going until the whole card is dumped, but seen this is a very slow process it might take a while
I'll edit the post if it's done.
edit: this worked without any problems
openpandora:/media$ sudo dd if=/dev/sda |bzip2 >/dev/null
7839744+0 records in
7839744+0 records out
4013948928 bytes (4.0 GB) copied, 6230.45 s, 644 kB/s
The reason why I did this is because on that 4gb card I have put a copy of the Pandora distro and had sometimes bizarre issues.
Who looked quite random and I/O related .
I know there will be reply's like "buy a other/decent Sd card" , but the point is that at least the pandora is much more "picky" about Sd cards than other systems.
I use those cards already some time on my N800 for example and there I never had any issue that looked like SD card related.
If some people would sacrifice some CPU time on their Pandora doing the same ( sudo dd if=/dev/mmcblk0 |bzip2 >/dev/null or sudo dd if=/dev/mmcblk1 |bzip2 >/dev/null )
to test their cards then that would be very good to see if other people have the same issue.
at the very least it might help to establish if it's only a rare/specific to certain cards occurrence or not.
If someone would have any idea of what more diagnostic info to provide , or has other idea on how to test these cards faster, please let me know.