SD vs CF flash cards?

[SharpEnd]

Can someone point me to (or fill me in) a quick primer on SD versus CF memory cards?  Which ones are better, more functional, etc. for the Z, and the pros and cons of each.

Can\'t wait to get my Z C860 next week!

Thanks!

[DrWowe]

SD cards are smaller, slightly more expensive for equivalent storage (although this gap is shrinking fast), and access is somewhat slower.  This can be a problem because sometimes movies have trouble playing from SD cards if the bitrate is too high. On the Zaurus, you can only use the SD slot for flash storage cards.  The driver for the SD slot is binary only, which can be a problem if you want to experiment with alternate kernels.

CF cards are bigger, slightly cheaper per megabyte, and go up to much larger capacities.  (I think the current max is 4GB, but it increases every year).  You can even buy \"microdrives\" which are basically a standard hard drive shrunk down into a tiny package.  CF is based on PCMCIA, which is a venerable technology invented for laptop expansion a very long time ago.  The CF slot is useful for many more things besides storage - you can put all kinds of devices in there, network/wireless cards are just one common example.

Because the CF slot is so much more flexible, most people use the SD slot for holding a memory card with all the programs and data, and use the CF slot for other things like network access.

[ScottYelich]

did I just see a 12 GB flash? or was it 16GB?  anyway, it was a cool $9999.99 etc.

To me, the $300 range is tops for storage cards.  a $150 muvio is within that range :-)

Scott

[rikiya]

I saw that one too... 12 GB world\'s largest capacity and yep $9999 now they reduced the price of the 6 GB one from $7999 to $3999

[DrWowe]

Um, I stand corrected.  Hands up, everyone who has a ]4gig CF card.  

[SharpEnd]

SD cards are smaller, slightly more expensive for equivalent storage (although this gap is shrinking fast), and access is somewhat slower.  This can be a problem because sometimes movies have trouble playing from SD cards if the bitrate is too high. On the Zaurus, you can only use the SD slot for flash storage cards.  The driver for the SD slot is binary only, which can be a problem if you want to experiment with alternate kernels.

Because the CF slot is so much more flexible, most people use the SD slot for holding a memory card with all the programs and data, and use the CF slot for other things like network access.

So I guess I need one of each?  A CF card to store/load kernels, SD card for daily use while I have a CF wifi card in that slot?
Any brand SD or CF cards particularly better than others, or all they all pretty much the same?  
Any recommendations for a low-power usage yet good function CF wifi card?

Thanks!!

[patrick]

A lot of SD cards won\'t work with the Zaurus (or the Dell Axim or the Tungsten T3 or etc.). Worse, it isn\'t really possible to tell ahead of time which cards will and won\'t work - with the possible exception of that the ones which have been manufactured in Japan seem to work consistently. But you usually can\'t tell if the card was made in Japan until after you\'ve bought it, opened the package, and looked at the back of the chip. For gory details, see: http://sdprob.aximsite.com/. There\'s a list at http://sdprob.aximsite.com/theproblemlist.htm which might give you an idea of which models are and aren\'t flakey. SanDisk cards are particularly bad.

Does anyone know if this is still an issue with recently manufactured Zauri?

patrick charles hayes

[SharpEnd]

A lot of SD cards won\'t work with the Zaurus (or the Dell Axim or the Tungsten T3 or etc.).
For gory details, see: http://sdprob.aximsite.com/. There\'s a list at http://sdprob.aximsite.com/theproblemlist.htm which might give you an idea of which models are and aren\'t flakey. SanDisk cards are particularly bad.

Thanks, Patrick, for the tip and the link.  Looks like the Lexar card that I was looking at is OK, as is Simpletech (which is supposed to be a very fast SD card, from what I\'ve read).  Will look into it further before buying.  

Any tips as to size to purchase, supposing that I\'m going to be flashing roms?


Mike

[offroadgeek]

Any tips as to size to purchase, supposing that I\'m going to be flashing roms?

Mike

I would make sure at least one card (either SD or CF) is 256mb or larger.  With the C series Zs, you may find the need to do a NAND restore, and the NAND files are generally ]130mb.  btw - I think people have had more luck with flashing with a CF than a SD card, but I could be completely wrong (someone please correct me!).

Also, you may want to check out the following How-To docs, good reading and more knowledge...

Compatibility and Support
SD and CF FAQ

offroadgeek

[SharpEnd]

So after reading the FAQ, I\'m actually more confused as it mentioned that the Z can\'t take advantage of the extra speed of SD cards (is this accurate?).  I\'m wondering if one SD card which is faster than another, or one CF card which is faster than another, is worth the price difference?  Or just buy the cheapest card, because speed doesn\'t matter?

[DrWowe]

\'m actually more confused as it mentioned that the Z can\'t take advantage of the extra speed of SD cards (is this accurate?).

I\'ve been wondering about that too!

Here\'s what I (think I) know:  There\'s an older standard called MMC, which is the original basis for SD.  MMC cards look just like SD cards, except they have 2 fewer pins and are a tiny bit thinner.  They are also compatible with SD slots.  (you can use an MMC card in the Zaurus just fine)

The SD card builds on the MMC standard, and features a slow compatibility mode where they mostly function like an MMC card.  However, SD cards also support some faster transfer modes that aren\'t MMC compatible.

Now, some drivers apparently only support the slow MMC modes.  The question is whether or not the Zaurus does this.

[Flash]

I have been using both the Lexar and SanDisk SD cards, both 256mb. Not a problem with either one. I also have NOT had any luck trying to load a ROM image from SD, no problem on CF. Go figure. I understand that initially there was a quality control issue with the main factory that supplies these chips. Most prominent were the ones sold by SanDisk, they were the first to market, therefore the first to fail. Recent product has been quite good, although I dont know about the claims of speed as such.

[DrWowe]

On my 5600, I was able to flash the ROM from an MMC card.  I changed kernels and distributions several times with no problem.

[rgrep]

Although I had a lot of trouble with a 256MB SanDisk SD card, my new Kingston 512MB SD works perfectly for NAND Backups & Restores and installing new ROMs (I have tried Cacko and pdaXrom so far).

I recommend that when you buy a new card (either SD or CF) you do a badblock scan before using it.  I had trouble with my SanDisk card since I first started using it but it wasn\'t until I did a badblock scan that I realised only the first 108MB was free of bad blocks!  I partitioned the card so I could only use these first 108MB and the card worked perfectly.  I returned the card to SanDisk, got my money back and bought a Kingston instead.

[Miami_Bob]

C860 with 512Mb SanDisk secure digital card & 512Mb SanDisk CF card. No problems with either one so far (knock silicon!).


Bob W
Miami FL