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Compact flash cards issues may cause high CPU activity Laptop Macs
We have a G4 iBook running 10.3.9 that has been running extremely sluggish and very hot -- too hot to rest your hand on the lower left corner. A visit to the Activity Monitor confirmed 100% CPU usage, and the culprit was a process named fsck_msdos. This had me confused: I know what fsck does (it verifies and fixes disk volumes), but I do not have a FAT-formatted volume connected.

Further experimentation led me to a defective CF card. Apparently, when diskarbitrationd attempts to mount the volume, it launches fsck_msdos. And fsck_msdos appears to be brain-dead: if it cannot access the volume, it just sits there and consumes CPU cycles...all of them, as long as the machine is on, whether or not you remove the defective card.

The solution is to simply kill fsck_msdos in the Activity Monitor, and read the defective card through the camera's USB interface. Surprisingly, a search of the Apple forums in the 10.3 discussion threads produced exactly one hit, which had nothing to do with the problem.
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Compact flash cards issues may cause high CPU activity
Authored by: satcomer on Dec 16, '07 06:46:39AM
Compact flash cards issues may cause high CPU activity
Authored by: greed on Dec 16, '07 09:23:43AM

I'm not surprised fsck_msdos gets run on the card; filesystems are always verified before being allowed to mount read-write. Some filesystems have "sync" marks on them, so the mounter knows right away if they were taken offline cleanly. Otherwise, or if the mounter can't tell, the filesystem gets fsck(8)ed first.

Apple's had some bugs in fsck over the years; there was an integer truncation error in the 10.0-10.2 fsck_hfs and I sent them a little patch and a little bug report, and they fixed it in Tiger.
I<heart>Open Source... I can fix bugs if I have to.
But sometimes, I H8 Open Source... I have to fix bugs.

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Compact flash cards issues may cause high CPU activity
Authored by: macmouse on Dec 16, '07 10:16:44AM

You do realize, that most flash devices (Compact flash, USB thumb drive, Digital Cameras) use FAT32 for their filesystem because it is the most compatible (between mac, windows and linux). So unless you have reformatted the disk using Disk Utility, it is still going to be FAT32. I have yet to have heard of a digital camera that didn't use FAT32, and when inserting a different filesystem (HFS, NTFS) the camera would refuse to work because it could not understand what was on the memory card, and therefore not be able to save the images to the flash disk.

Under the assumption that your flash drive IS formatted using FAT16 or FAT32, then probably the reason fsck_msdos is freezing is because the filesystem on the flash disk has become so corrupt that it doesn't know what to do with it. You can do a search on or, and there is a number of programs that will do data recovery off camera flash cards, if the pictures are that important to you.

I would also recommend you get one of those "12-in-1" (or heck, now 52-in-1!) USB flash card adapters, and access the card directly because you know your camera is defective, and it is possible that the USB/flash circuitry is defective too (but operates well enough to let you see /some/ stuff).

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Compact flash cards issues may cause high CPU activity
Authored by: pbilbao on Dec 16, '07 01:23:10PM

Just bought a digital photoframe made by HP and I am having some problems with the configuration. Some photos don't follow and a black screen shows for 5 seconds and then the next photo. The frame is compatible with almost all the cards on the market except maybe the SDHC which is not a problem. My question is mainly about selecting and copying the photos from iPhoto to the cards. Which is the proper way to do it?

Thanks from sunny Spain


Madrid, Spain

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