SD vs CF flash cards?

[SharpEnd]

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

I think I found a couple of bargains on SD cards:

Buy.com has the Simpletech Pro-X fast SD 256mb for $60.69 : http://www.buy.com/retail/product.asp?sku=...02&loc=101&sp=1

and Sandisk 512mb SD for $99.99 today only (assuming that this is the made in Japan model which works): http://www.buy.com/retail/clearance/dotd.a...14&sku=70012130

(no connection to the seller - just passing on some deals - I grabbed one of the Simpletech cards)

Mike

[ScottYelich]

my 512mb lexar sd goes offline whenever I give it any sustained writes -- ie: whenever I write to it.

[SharpEnd]

my 512mb lexar sd goes offline whenever I give it any sustained writes -- ie: whenever I write to it.

Is it a \"made in Japan\" model, or made in Singapore?

Look here, as someone posted earlier: http://sdprob.aximsite.com/theproblemlist.htm

[zbones]

I have tested several sd and cf cards for speed, and I have not found a card that will do more than 1mb per second sustained on either a 5500 or an slc760.

the badged standard lexar 256 performs at the same speed as a badged 32X lexar 256mb card on my zaurus, but not on my PC!

In my usb2 card reader the 32x card wins hands down!

Anybody who has a card (cf or sd) that can achieve a sustained throughput of more than 1 mbyte per second in a zaurus then I want to know, as I will buy one.

The lexar 32X that I tested was supposed to go faster than 9mbytes per second. But it got no furthet than 1mb/sec in my tests on both zauri and the c760 definately out performed the 5500 with the same card.

CF also always outperoms sd, in my tests, but never crosses the 1mb/ps threshold leaving me to believe that either the cards are not fully wired or the zaurus bus is not upto the job.

Prove me wrong, if you can! I would love to have a faster card in my zaurus.

Peter

[SharpEnd]

CF also always outperoms sd, in my tests, but never crosses the 1mb/ps threshold leaving me to believe that either the cards are not fully wired or the zaurus bus is not upto the job.

Peter

Thanks for the info, Peter, this is good to know.

[Zazz]

I get around 1600 kB/s with both a panasonic and a simpletech pro-x 256MB SD card when I dd 10MB from /dev/zero to /mnt/card. Is there a better way to measure the speed?

[fpp]

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.

(newbie question, sorry  )

How do you do a \"badblock scan\" ? Directly from the Zaurus, ot from a PC through a card reader ?

Thanks,
fp

[DrWowe]

If you format it ext2, you can do the badblocks scan while formatting.  Use the -j option.

[fpp]

Thanks !

Is there any way to check an existing FAT32-formatted card, without erasing it ?

[zbones]

I get around 1600 kB/s with both a panasonic and a simpletech pro-x 256MB SD card when I dd 10MB from /dev/zero to /mnt/card. Is there a better way to measure the speed?

That\'s a good choice as /dev/zero is not going to be a bottle neck in terms of read.   However 10mb may not be a large enough file for a true test.

You have 64mb ram, some of that will be used as buffer cache so to defeat the effects of that you may have to write a larger file.

Just to prove the point, post the exact command you ran and I will try it on my two sd cards.  Then the only difference would be the make of sd card in our test.
Peter

[freizugheit]

I have used  256 MB SD card made by Hagiwara Sys-Com from Japan  as my system backup disk since 09/2003.  I have used Sandisk CF cards, ranging from 32 MB to 256 MB, since 2001 for various PDA.  

I have no p reliability and quality problem with memory cards from both bands.

[Zazz]

I get around 1600 kB/s with both a panasonic and a simpletech pro-x 256MB SD card when I dd 10MB from /dev/zero to /mnt/card. Is there a better way to measure the speed?

That\'s a good choice as /dev/zero is not going to be a bottle neck in terms of read.   However 10mb may not be a large enough file for a true test.

You have 64mb ram, some of that will be used as buffer cache so to defeat the effects of that you may have to write a larger file.

Just to prove the point, post the exact command you ran and I will try it on my two sd cards.  Then the only difference would be the make of sd card in our test.
Peter

The following is with a vfat-formatted 256MB Simpletech Pro-X SD card. I include a sync command into the timing to exclude buffer effects.

root@zaurus(pts0):~# time sh -c \'dd if=/dev/zero of=/mnt/card/dump bs=1024k count=10; sync\'
10+0 records in
10+0 records out

real    0m5.942s
user    0m0.060s
sys     0m5.880s
root@zaurus(pts0):~# rm -f /mnt/card/dump
root@zaurus(pts0):~# time sh -c \'dd if=/dev/zero of=/mnt/card/dump bs=1024k count=20; sync\'
20+0 records in
20+0 records out

real    0m11.741s
user    0m0.040s
sys     0m11.680s
root@zaurus(pts0):~# rm -f /mnt/card/dump
root@zaurus(pts0):~# time sh -c \'dd if=/dev/zero of=/mnt/card/dump bs=1024k count=40; sync\'
40+0 records in
40+0 records out

real    0m23.596s
user    0m0.040s
sys     0m8.430s
root@zaurus(pts0):~# rm -f /mnt/card/dump
root@zaurus(pts0):~# time sh -c \'dd if=/dev/zero of=/mnt/card/dump bs=1024k count=80; sync\'
80+0 records in
80+0 records out

real    0m47.895s
user    0m0.010s
sys     0m26.370s

Not sure why the sys time is too small for the larger file sizes. The real time is correct. These values are reproducible within a few percent.

[zbones]

root@zaurus(pts0):~# rm -f /mnt/card/dump
root@zaurus(pts0):~# time sh -c \'dd if=/dev/zero of=/mnt/card/dump bs=1024k count=80; sync\'
80+0 records in
80+0 records out

real 0m47.895s
user 0m0.010s
sys 0m26.370s

Zazz, thanks for that, I get :-
real 1m41.504s
user 0m0.040s
sys 1m28.640s

So your card is indeed over twice the speed as my lexar.

I still doubt that that is anywhere near the mf quoted speed though, do you know what that is?

Also, what zaurus/rom/kernel was this on?

*EDIT*
Just done a search, c860 with pdaxrom, was it overclocked at all as that does make a difference.

[Zazz]

I still doubt that that is anywhere near the mf quoted speed though, do you know what that is?

The manufacturer hyped speed is up to 10MB/s. I\'m not sure if the card itself is the bottleneck or rather the bus speed of the Z. Does anyone have a faster card?

Also, what zaurus/rom/kernel was this on?
*EDIT*
Just done a search, c860 with pdaxrom, was it overclocked at all as that does make a difference.

Yes, C860 with pdaxrom, not overclocked.

[zbones]

Yes, C860 with pdaxrom, not overclocked.

Just to rule out any sash type jigory pokery optimization stuff, could you possible test your internal flash?

I get 42.120s for 80m, 23.465s for 40m and 4.940s for 10mb.
I used the same command line just changed count= to 10,40, and 80.
I did a few as on the pdaxrom I doubt you will have 80mb free.
Oh, the sync line was left in as well.

Cheers,
Peter