Re: SD Card reader
From: 7 (website_has_email_at_www.enemygadgets.com)
Date: 11/19/05
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Date: Sat, 19 Nov 2005 03:06:02 GMT
Larry Qualig wrote:
>
> 7 wrote:
>> Bobbie Gill wrote:
>>
>> > On Sat, 19 Nov 2005 01:41:33 +0000, 7 wrote:
>> >
>> >> Bobbie Gill wrote:
>> >>
>> >>>
>> >>> I need a bit o' help with a problem.
>> >>> I'm running Suse10 and everthing works fine, except for my SD reader.
>> >>> I can read from the SD card with no noticeable lag, but writing to
>> >>> the card is completely different.
>> >>> When I drag and drop a 4Meg file from the reader to the desktop it
>> >>> takes less than 5 seconds to copy it over.
>> >>> When I take a similar size file and copy it to the SD card it takes
>> >>> about 6 minutes. I kid you not.
>> >>> It doesn't matter if I'm logged in as root or as a user, the times
>> >>> are still the same.
>> >>>
>> >>>
>> >>> Any help would be greatly appreciated.
>> >>
>> >>
>> >> Writes in general are slower than read operation but not that slow.
>> >> Test with liveCD like Mepis / Knoppix etc to see if a hardware
>> >> problem exists. I have no troubles with read or write this way
>> >> using off the shelf card reads and get a couple of megabytes per
>> >> second sustained read and write speed.
>> >> Write could be done through SPI operating mode, but that is
>> >> way slow compared to SD operating mode. May be your card or
>> >> card reader, if not the software is defaulting to SPI mode
>> >> of writing. Another possibility is dirty contacts or a source
>> >> of electrical noise / interference causing CRC errors to slow
>> >> your communications between card and card reader.
>> >>
>> >> Could test it all with separate card reader (about $10) and
>> >> separate 256MB card (about $10).
>> >
>> > I'm making some headway on this issue.
>> > It seems there is a problem with Suse 10, USB drives and 'sync'
>> >
>> > please see:
>> > https://bugzilla.novell.com/show_bug.cgi?id=105871
>> >
>> > I still haven't figured out what to do yet.
>>
>> Reading the buzz of activity around the problem,
>> it seems the coders are on the job and will probably
>> have a fix out soon.
>>
>
>
>> Reading further, you could format the SD card as ext3
>> or Reiser and the problem goes away.
>
>
> Warning - If this card goes into some device like a digital camera it
> is very likely that the camera/device will **not** recognize a Reiser
> or ext3 file system.
Should qualify that by saying its only devices limiting their
support to FAT file formats have this problem.
More opportunities for Linux friendly companies to bring
out hardware using better file systems.
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