"Unknown files"..."Corrupt files"...&quo

3335 Views 11 Replies 5 Participants Last post by PetrolDave, Aug 17, 2005

HX_Guy

Discussion Starter · Aug 15, 2005

I'm running into a problem with my SD card and I want to know if anyone here has experienced this.

The card I am using is a Sandisk 2GB card formated with FAT16 file system. The card is about 1.1GB full.

What is happening is about a week after I start using the card, I get the above mentioned error messeges. Each time I switch to the SD card, I get a different messege...either "Unknown files", "Corrupt files", or "No media".

I am making no changes at all to the SD card, I don't even take it out of the slot. It seems to work fine immediately after copying MP3s to the card, then over the course of a week it starts to take a bit longer to load the SD card, until I finally get the error messeges.

When loading the SD card on the PC, everything seems fine. I have to reformat the card and then recopy the songs...and the RNS-E works again, for about a week.

Any ideas?

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PetrolDave

· #2 · Aug 15, 2005

Re: "Unknown files"..."Corrupt files"...

HX_Guy said:
The card I am using is a Sandisk 2GB card formated with FAT16 file system. The card is about 1.1GB full.

What is happening is about a week after I start using the card, I get the above mentioned error messeges. Each time I switch to the SD card, I get a different messege...either "Unknown files", "Corrupt files", or "No media".

I am making no changes at all to the SD card, I don't even take it out of the slot. It seems to work fine immediately after copying MP3s to the card, then over the course of a week it starts to take a bit longer to load the SD card, until I finally get the error messeges.

When loading the SD card on the PC, everything seems fine. I have to reformat the card and then recopy the songs...and the RNS-E works again, for about a week.

Any ideas?

Is yours an MLC SD card, or hi-speed? MLC cards are designed to work with digital cameras and allow a certain number of data-dependent errors. These are acceptable (i.e. not seen when the picture is viewed), but can cause problems when storing data that cannot accept errors e.g. MP3.

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HX_Guy

Discussion Starter · #3 · Aug 15, 2005

Not sure if it's MLC or not...how would I find out?

http://www.newegg.com/Product/Product.asp?Item=N82E16820180627

That is the SD card I am using.[/url]

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AudiA4B6US

· #4 · Aug 15, 2005

As far is a know, the SanDisk is a normal SD card and the SanDisk Ultra is a high speed SD. I have the SanDisk Ultra 2GB and never had problems (1.7GB data), and I have a 512MB SanDisk Ultra which is 99% full, no problem either.

Can't say anything about the normal SanDisk although it has been mentioned several times that you don't need to use high speed SD cards for the RNS-E and your's should work fine.

When you got the card, did you format the card or did you just take the card as is? I did format my cards under XP with FAT16 and as I said, never had a problem (now after 4 months and up to 109F outside temps in Chicago).

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PetrolDave

· #5 · Aug 15, 2005

HX_Guy said:
Not sure if it's MLC or not...how would I find out?

http://www.newegg.com/Product/Product.asp?Item=N82E16820180627

That is the SD card I am using.[/url]

I've logged a support request with Sandisk to find out.

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PetrolDave

· #6 · Aug 16, 2005

Got the reply from Sandisk:

Sandisk said:
Hello Dave,

Thank you for contacting SanDisk Technical Support

Yes the 2GB SD card is MLC.

Best Regards,

Ofir

SanDisk Technical Support

If you have any further questions, please feel free to reply to this e-mail or contact our technical support department toll free at 866-SANDISK (866-726-3475). Have a Great Day.

The description "Hi-Speed" or "High Speed" can be misleading - the higher speed is a side effect.

On "normal" SD cards many manufacturers use MLC memory devices - which are cheaper, slower and (importantly for us) prone to errors.

On "high speed" SD cards they use conventional memory devices - which are more expensive, faster and (importantly for us) don't generate errors (unless they are faulty).

I personally would never buy MLC cards for any device (camera, RNS-E, MP3 player) - I don't want random errors in my pictures or my music!

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AudiA4B6US

· #7 · Aug 16, 2005

So that means that for example the SanDisk Ultra should be preferred even though the SanDisk (non Ultra) would be fine in regards to speed? I may have simply been lucky that I had chosen the Ultra (because I planned to use it in my Canon SD300, Treo 650 and RNS-E) but I haven't seen any issues so far.

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HX_Guy

Discussion Starter · #8 · Aug 16, 2005

Thank you for checking. I'm going to return the one I purchased and buy the Ultra version of it.

Thanks again.

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PetrolDave

· #9 · Aug 16, 2005

AudiA4B6US said:
So that means that for example the SanDisk Ultra should be preferred even though the SanDisk (non Ultra) would be fine in regards to speed? I may have simply been lucky that I had chosen the Ultra (because I planned to use it in my Canon SD300, Treo 650 and RNS-E) but I haven't seen any issues so far.

Spot on.

I use the ByteStor Hi-Speed cards, but every non-MLC card should be fine.

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Downunder

· #10 · Aug 17, 2005

I have been playing around with a Kingston 1Gb (previously in my Ipaq, guess it's an MLC card) for about a week now trying to get my music the way I want it, before I get a couple of 2GB cards.

It would seem that the card only gets corrupted when either I try and do a concurrent write or do several updates or additions to already stored files. It doesn't seem to make any difference with the type of format (FAT 16 or 32).

This seems to be consistant with previous comments about the way MLC cards store data.

I am now storing the primary copy on the PC in the required order with all the name changes etc. for each card and then fully re-loading the card each time there is a change.

Doing it this way the card remains fully stable (so far)

With USB II the time to reload is not significant ... go and get a coffee and it's done.

There still seems to be a reasonable difference in $'s between MLC and non MLC cards so this may be an option for some.

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wingnut1122

· #11 · Aug 17, 2005

Couldn't find anything regarding MLC's accepting more errors than high speed cards, but I found this explaination between SLC and MLC.

"Note that there are two different types of memory cells used in CF memory. The first and fastest is called a Single Level Cell (SLC) which stores 1 bit in each cell. There's also a slower (but cheaper) architecture called Multi Level Cell which stores two bits in each cell. Both technologies are getting faster, but the fastest cards are always based on SLC technology. SLC technology also uses a little less power then MLC, so that's another advantage. The main advantage of MLC is in cost per megabyte."

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PetrolDave

· #12 · Aug 17, 2005

Here's what one manufacturer, ByteStor, who makes both MLC and SLC cards says:

ByteStor said:
If you intend using the card for: high-megapixel digital cameras, movie recording, in applications where speed could be an issue or in various SD devices, a ByteStor Hi-Speed SD card is recommended.

MLC (Multi-Level-Cell) SD cards can hold more data per cell. Therefore they have a lower production cost.

MLC cards are generally slower but will work in many devices.

It looks like the RNS-E should be classed as a high speed device, so some MLC cards will work fine but SLC cards are recommended.

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