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I too have done research on Compact Flash cards, and have come to the same |
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conclusion. |
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My company uses Compact Flash (CF) as our storage for our OS and software on |
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our outdoor kiosk. Sadly I was forced to use Windows Embedded XP (XPe); the |
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software guys at my company are all windows guys (I'm a hardware engineer by |
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education and trade). Early on I did not use a "write filter"* on the |
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systems and I have had a couple of compact flash die because of to many |
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writes to the CF. |
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We also use DiskOnChips, which has had were leveling since the beginning of |
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there life. |
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You could partition the CF and mount the main partition read only and a small |
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partition read/write and have your application write to that partition only |
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when needed to store data. Or remount the root partition write only when |
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needed. |
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* the write filter is a XPe thing to limit the writes to the compact flash, |
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basicaly it creates a small ram disk and write are done there first and then |
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"flushed" to the compact flash later |
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heath holcomb |
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On Friday 08 October 2004 02:04 am, stephane ancelot wrote: |
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> Hi, |
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> A few notes about compact flash, I recently made a research about cflash |
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> products. |
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> The main safety in compact flash products is in the availability of the |
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> wear leveling function (secure mode) |
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> low cost cflash do not include this capability , for this reason , you will |
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> need to use jffs2 , to allow sector repartition over the disk. |
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> |
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> However more robust products (sandisk / lexar) include the wear leveling |
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> function in the card and it is completely transparent from the user, you |
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> use it as a single normal ide disk. |
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> Furthermore, lifetime and throuput bandwidth of these products is faster |
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> than common camera cflash. |
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> |
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> If interested in I could give you more details on how to check if your |
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> cflash card supports wear leveling . |
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> Best Regards |
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> Steph |
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> |
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> > One solution here for him could be to use squashfs + jffs2. |
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> > I wont explain how to do that. But it's probably worth his time to |
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> > research it. The openwrt project is making use of this type of setup now |
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> > to make failsafe systems that live on flash. http://openwrt.org |
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> > |
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> > > > Furthermore , the system may stay in a readonly partition , but we |
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> > > > have to plug our application in this system that should be setted up |
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> > > > on a separate partition because we should be able to send updates for |
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> > > > it . and the user may load save files on it . |
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> > > > |
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> > > > What are the gentoo tools to allow that ? |
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> > |
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> > sys-fs/squashfs-tools-2.0_p2 |
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> > sys-fs/mtd-20040825 |
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> |
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> -- |
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> gentoo-embedded@g.o mailing list |
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-- |
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Heath Holcomb |
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Project Engineer |
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Texas Digital Systems |
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-- |
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