sl5600 - SD flash keeps going read-only

[DrWowe]

I have had similar problems with an SD card (can\'t remember what brand it is).  But before I used it in my SL5600, I had used it for a while with an iPaq and had no problems.  Maybe there\'s bugs in the Zaurus SD driver?

[freckface]

I just got off the phone with Sharp\'s Zaurus support.  They told me that they have not recieved any (many?) tech support calls about this problem.  However they did sound highly interested in resolving this issue!

They have asked me to reformat my Lexar SD card and try to get it to work that way.  If (when) that doesn\'t work, they have given me a phone number of a Zaurus \"guru\" at sharp who may be of additional assistance.  If anyone would like to assist me in attempting to resolve this issue, I would greatly appreciate it.

[pakman]

There does seem to be a general problem with filesystem corruption on SD storage - for background reading from someone who has really got his teeth into the issue, take a look at http://sdprob.aximsite.com/ . There are also four tests to check whether a particular card is \'safe\' or not that could be trivially converted to Unix scripts.

Zaurii don\'t feature on this site, but we (as a community) could change that by letting the site maintainer know of our own experiences. It looks to me that he would be happy to add our info.

I agree that buying SD memory is a bit of a lottery - there clearly has been a problem with the Zaurus/SanDisk combination for cards of 256Mb and above, and Lexar was generally considered safe for the Zaurus. It may be that this picture is changing. My own experiences (for what they are worth) are at  http://externe.net/zaurus/forum/viewtopic.php?t=812

Regards.
P.

[zbones]

See my latest post in this thread for an interesting turn to the sandisk/lexar sd debate.

http://www.zaurususergroup.com/index.php?n...=viewforum&f=72

I just got off the phone with Sharp\'s Zaurus support. They told me that they have not recieved any (many?) tech support calls about this problem. However they did sound highly interested in resolving this issue!

The person you spoke to is either very new, or just wants you to go away happy.  :wink:

I would like you to persevere however, and let us all know what their \"current stance\" is on this issue, but don\'t hold your breath waiting for a resolution.

Sharp are very aware of numerous SD problems, and there are many different problems that do not seem to be brand specific.

1) works fine as fat, but not ext2.
2) goes ro after heavy access (all formats).
3) bad blocks (all formats).
4) suspend/resume problems.
5) slows the machine to a crawl during heavy read/write access.
6) crash and reboot during read/write access.

Some of these are related, others are not. There are also many cards that have no problems whatsoever. Some times you can get two cards from the same company which appear to be identical even down to similar serial no\'s.  One will work fine, the other will exhibit one or more of the above set of problems.

As others have stated, it\'s not a sharp/zaurus only issue.

Peter.

Peter.

[happycheesecake]

Hi folks

Zbones has just contacted me regarding your favourite gismo and SD cards, and I thought I\'ll try to answer what *could* be going wrong.

First things first, there are two issues with SD cards: corrupted data and slow write times.  

Corrupted data
My guess is that your read-only problem is being caused by an issue like the one that affected Dell Axim X5 users; except in the Zaurus\'s case the card goes read only.  As you probably know, SD cards have a form of File Allocation Table, to determine when an area of the card is populated with data.  What you probably don\'t know is that there is an extension to this FAT to handle data security (i.e. the \"Secure\" part of SD cards...)  Now, our \"friends\" at Sandisk, the well known memory card manufacturers created a series of SD cards branded by themselves and others (including Lexar) with a (shall we say) sub-standard controller on the SD card.  This controller caused buffer over-flow errors during a write operation causing corruption to the secure part of the SD card.  This can lock the card VIA SOFTWARE to a secured-state, i.e. read only!  (Sandisk branded cards have a code on the back in the format NNYYMMnN where NN are characters, n is the series code, YYMM are year & month of manufacture...)  Note that Sandisk have revised their cards a number of times during 2003 & 2004...

Slow write speeds
SD cards are just like other memory cards (i.e. CF, MMC, MS, xD, SM, etc) where they emulate an ATA hard drive.  Unfortunately, some memory card controllers in devices (like PDAs) are not too compatable with certain brands of SD cards, and what they do is drop the i/o speed to mantain reliable access with the SD card.  For example, I own over 600 SD cards.  I actually only use 2 - a 256mb SimpleTech and a 512mb Panasonic.  The SimpleTech, based on a Hitachi SD memory chip, is 300% faster writing than the Panasonic in my PDA (a Ipaq 2210) but the same speed in my camera (Minolta Dimage Xt).  I guess you folks need to identify what cards are faster by timing a large file write to your SD cards and then posting the results...

Hope this helps.

[zbones]

So my lexar and sandisk cards could well be designed by the same people.

Anybody with a simpletech card care to run some speed tests on a zaurus?

Anybody with an sd card capable of more than 1mb/sec sustained write speed on any zaurus?

I feel a purchase could be on the horizon.

Peter

[DrWowe]

I misspoke.  The card I was referring to in my earlier post is actually an MMC card that I put in the SD slot.  MMC cards don\'t have all the security junk.  So, there\'s something else going on as well.