Author Topic: Fast SD access?  (Read 2204 times)

Foxdie

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Fast SD access?
« on: November 14, 2003, 07:00:26 pm »
Heya one and all, I\'m thinking of buying something like this on ebay: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...&category=18871 for my C760

I know it\'s a SanDisk card and they apparently have a reputation for failing (another post has these details) but can the Z take advantage of what the auction quotes as \"8 times the speed of Regular SanDisk!!!!\"?

Can the Z\'s SD port run at 9MB/sec or so is quoted?

Also is there any steps I can take to make sure my SD card doesn\'t fail if I buy one like a SanDisk one for my C760?
Jason "Foxdie" Gaunt
HTC Universal G4 with 2GB SD card running Debian Titchy Linux
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tumnus

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Fast SD access?
« Reply #1 on: November 17, 2003, 05:54:07 am »
Nope. SD cards generally run at the same speed of MMC cards because the Zaurus only uses 1 data channel, whereas you need to use all 4 channels to get the full speed from SD cards.

You can look here for user reports on SD card compatibility: http://zaurus.knightfire.com/
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Foxdie

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Fast SD access?
« Reply #2 on: November 17, 2003, 06:51:41 am »
I don\'t suppose you know what the max bitrate is for 1 data channel SD access do you?
Jason "Foxdie" Gaunt
HTC Universal G4 with 2GB SD card running Debian Titchy Linux
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wirawan0

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Fast SD access?
« Reply #3 on: March 16, 2004, 10:52:23 am »
Tumnus: Is there any use to buy a fast SD card, say, 32x? I saw one on buy.com for Lexar 256 MB, the price was quite decent. At what rate will the card\'s speed no longer matters, since you say we won\'t be able to get the full speed of the SD card?

zbones

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Fast SD access?
« Reply #4 on: March 16, 2004, 05:00:31 pm »
The 32x 256mb lexar sd is the same speed as the standard 256mb lexar.

My test results for this were on the old dev board, but see here for some sd/cf timings :-

http://www.zaurususergroup.com/index.php?n...iewtopic&t=2292

So you won\'t get anywhere near 9mb/s raw speed.  The faster cards are only usefull if you use them or plan to use them in other devices.

Or maybe the 6000 and c970 will utilise the extra speed.

Peter
Zaurus cl760, cacko QT rom. Zaurus sl5500 with TKCrom 1.0.
512mb Kingston cf card, 256mb Sandisk sd card, Lexar 256mb sd card.
Bluemonkey bluetooth card <-> Sony Ericsson k700i for gprs.
Buffalo WLI-CF-S11G wifi card. Haicom 303 mmf gps cf/seral card.

zbones

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Fast SD access?
« Reply #5 on: March 17, 2004, 07:29:50 pm »
I may have to \"back peddal\" a little here after the posts in this topic :-

http://www.zaurususergroup.com/index.php?n...iewtopic&t=1915

The so called \"fast\" cards I tested, and the results posted to the dev forum to an earlier speed test all indicated that you will not get above 1mb/sec access using an sd card on the zaurus.  This doesn\'t mean that all \"fast\" cards will be the same.

Can anybody better 1mb/sec sustained writes on an sd card on a zaurus?

You need to write out a large file in order to defeat the effects of buffer cache.

Peter
Zaurus cl760, cacko QT rom. Zaurus sl5500 with TKCrom 1.0.
512mb Kingston cf card, 256mb Sandisk sd card, Lexar 256mb sd card.
Bluemonkey bluetooth card <-> Sony Ericsson k700i for gprs.
Buffalo WLI-CF-S11G wifi card. Haicom 303 mmf gps cf/seral card.

wirawan0

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Fast SD access?
« Reply #6 on: June 14, 2004, 12:44:50 pm »
Let me go OOT. Many people in this community have been having problems with ext2 partition in an SD care. Do you know why? This sounds bizzare. My Lexar 256MB died on me after 2 months. (It was reformatted as ext2.)

qx773

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Fast SD access?
« Reply #7 on: June 14, 2004, 09:18:25 pm »
Maybe you should use the noatime option in /etc/fstab on the line where your SD card gets mounted so that writes of the file\'s access time do not occur to the SD card every time that you access a file even for read-only operations.  I use the FAT file system so that I can easily exchange files with a Windows-based computer, so I don\'t have that problem.

wirawan0

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Fast SD access?
« Reply #8 on: June 14, 2004, 09:41:41 pm »
Actually, I used noatime already in the /etc/fstab file. But, whenever I used `mount\' to check the mounting options, it never mentioned `noatime\' for /mnt/card. Has anybody also experienced this kind of problem?

Also, provided that we don\'t use `noatime\' option. How many writes are there \"required\" to damage the card? And it is actually very strange, though. When I re-formatted the card to ext2 (eventually re-trying with FAT16 under Windows too), it now failed me. I\'m puzzled as to why the card broke down.