Date: Thu, 09 Apr 2009 20:01:29 -0700 From: perryh@pluto.rain.com To: rsmith@xs4all.nl Cc: freebsd-questions@freebsd.org Subject: Re: USB SD-card reader recognized, but not working, on 6.1 Message-ID: <49deb689.wo7pGx8gH2CQTOPa%perryh@pluto.rain.com> In-Reply-To: <20090409222047.GA44772@slackbox.xs4all.nl> References: <49de2c9a.QlCBOleCO/iBrMcf%perryh@pluto.rain.com> <20090409181009.GA38361@slackbox.xs4all.nl> <49de50cb.gcYrr9F1eSmdUBu9%perryh@pluto.rain.com> <20090409222047.GA44772@slackbox.xs4all.nl>
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Roland Smith <rsmith@xs4all.nl> wrote: > On Thu, Apr 09, 2009 at 12:47:23PM -0700, perryh@pluto.rain.com wrote: > > It's an SD card, not a "drive", so I had not expected it to be > > partitioned; but yes, it is: > > > > $ ls -l /dev/da0* > > crw-r----- 1 root operator 0, 244 Feb 14 15:09 /dev/da0 > > crw-r----- 1 root operator 0, 245 Feb 14 15:09 /dev/da0s1 > > That would suggest that there is a filesystem on there, doesn't it? It would certainly suggest there is a DOS "partition" table aka BSD "slice" table. I don't think it says anything about what the slice contains, however. > > $ dd if=/dev/da0 of=~/sd bs=1b > > > > That's been running for something like 45 minutes now, and based > > on the size of the output file it has read about a tenth of the > > card. > > Reading one byte at a time is bound to be slow. "dd bs=1b" is one block (512 bytes), not one byte. At least it seems to be working. I *would* anticipate problems if trying to read a umass device in units not a multiple of its native blocksize. > It could be that this USB chipset needs some "quirks" to work > correctly. like "Don't attempt to read more than 32768 bytes at a time" -- subsequent testing shows it to be OK up to bs=64b, but bs=126b fails -- or is there maybe a way to set that sort of limit in mtools?
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