Arch Linux

gradgrind

Member

From: Germany

Registered: 2005-10-06

Posts: 921

Any joy with compact flash?

I would like to use a compact flash card in an IDE adaptor, but it takes an awfully long time to boot because of all sorts of problems, apparently concerning DMA. It seems to have nothing to do with the kernel version, I've tried it with Arch, slax, kanotix, even an old slackware, and on three different machines. Various kernel boot paramaters (i.e. without acpi, apic, dma) also didn't help, though I was a bit puzzled that I still got dma messages with dma (ostensibly) disabled.

I suppose the strange thing is that after this long delay and the string of error messages, the thing seemed to work ok, it's just very impractical.

Has anyone any ideas?

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larch: http://larch.berlios.de

judfilm

Member

Registered: 2004-02-12

Posts: 229

Re: Any joy with compact flash?

You need an adapter that can handle DMA - pm me.
CF does work, once setup it can be just as fast if not faster in some cases. However, it does need some work to limit unnecessary writes (ie logging, swap, temp, pacman database)

Any tips/ideas/settings/scripts to make CF a better experience are most welcome (please share).

gradgrind

Member

From: Germany

Registered: 2005-10-06

Posts: 921

Re: Any joy with compact flash?

Thanks for the lead. I googled around a bit, and eventually found the details for enabling DMA on the adapter which I already have. It was extremely fiddly (I needed to get at two of the pins on the bottom, very difficult to access, row) but I managed to sever the connections and reconnect them to the right places on the IDE connector. So now it works fine and I have an old computer running larch as a media player.

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larch: http://larch.berlios.de

gradgrind

Member

From: Germany

Registered: 2005-10-06

Posts: 921

Re: Any joy with compact flash?

For anyone else who wants to attempt something similar: I'm afraid I didn't make a note of the websites with useful info, but somewhere on the SanDisk site there is an extensive compact flash specification, including the pin connections. I also found a circuit diagram for a cf2ide adapter (try googling 'cf-ide circuit diagram', I think that's how I found it).

But basically, to enable DMA, two connections need to be changed:

Compact flash pin 44 - IDE pin 29
Compact flash pin 43 - IDE pin 21

Beware of the unusual pin numbering on the compact flash, though. The top row is 1-25, the bottom row 26-50, with 1 being above 26.

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larch: http://larch.berlios.de