file system over CF flash

file system over CF flash

[丁厚永]

There is a CF flash of IBM MicroDrive in xilinx virtex-ii pro eval board ML300.
Can someone tell me what type of fs is used over such kind of flash device?

thanks in advance

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Re: file system over CF flash

[Magnus Damm]

There is no need for any special Flash file system, the Compact Flash itself keeps
track of things like wear levelling, sector size and command set of the flash devices.

The exported interface for a Compact Flash is just like any ATA Flash and under
Linux the standard IDE driver is normally used. The CF needs to be mapped into
some address space however, and this setup is usually taken care of by the PCMCIA
layer or the firmware/bootloader of your specific board.

So the Compact Flash itself does not limit you to any special kind of filesystem, but
I think the CF devices are shipped with some kind of FAT filesystem by default.

Then what this "xilinx virtex-ii pro eval board ML300" might assume is another thing.

/ magnus

On Sun, 1 Jun 2003 10:46:17 +0800
¶¡ºñÓÀ <nari_dhy@nari-china.com> wrote:

>
> There is a CF flash of IBM MicroDrive in xilinx virtex-ii pro eval board ML300.
> Can someone tell me what type of fs is used over such kind of flash device?
>
> thanks in advance
>
>


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Re: file system over CF flash

[Mark Hatle]

Magnus Damm wrote:
> There is no need for any special Flash file system, the Compact Flash itself keeps
> track of things like wear levelling, sector size and command set of the flash devices.

Just want to point out a common misconception on CF here.  While the unit will
do wear leveling, you MUST power cycle it for that to happen.  Each power cycle
pretty much locks down the sectors it is using.  Bizarre I agree, but you will
burn out a CF disk very quickly if you do not constantly power cycle it.  (We
had a customer experience that exact problem with the CF vendor's response being
"ohh you didn't know that?".)

CF disks are great for read-only, occasional writes, and "consumer devices"..
but are terrible for anything that you would expect long uptimes and moderate
writing.  (In this situation, the little IBM CF hard drive seems to work pretty
good, but I don't have any long term experience with failure/success on one of
those.)

> The exported interface for a Compact Flash is just like any ATA Flash and under
> Linux the standard IDE driver is normally used. The CF needs to be mapped into
> some address space however, and this setup is usually taken care of by the PCMCIA
> layer or the firmware/bootloader of your specific board.

--Mark


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Re: file system over CF flash

[Scott Anderson]

Hey guys, you missed where he said "IBM MicroDrive"...
On Saturday, May 31, 2003, at 07:46  PM, 丁厚永 wrote:
> There is a CF flash of IBM MicroDrive in xilinx virtex-ii pro eval
> board ML300.
> Can someone tell me what type of fs is used over such kind of flash
> device?

The MicroDrive is actually spinning media and does not have the typical
FLASH concerns that Magnus and Mark pointed out.  In this particular
instance, I believe Xilinx is shipping it with a DOS partition, a Linux
swap partition and an ext2 partition.

    Scott


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