The kernel doc's seem to say this is okay... (Score 2)

I'm curious about IDE software RAID as well. Here
are a couple bits of info that may be relevant. I
haven't tried any of this yet.

First, http://www.linuxhq.com/doc23/ide.txt
This claims 2.1/2.2 kernels have:

> - support for up to *four* IDE interfaces on one or more IRQs
> - support for any mix of up to *eight* IDE drives

And further in the document there is info on
configuring such a system, which claims that you
can run as many as 6 interfaces (3 controllers?):

> This is the multiple IDE interface driver, as evolved from hd.c.
> It supports up to six IDE interfaces, on one or more IRQs (usually 14 & 15).
> There can be up to two drives per interface, as per the ATA-2 spec.
>
> Primary: ide0, port 0x1f0; major=3; hda is minor=0; hdb is minor=64
> Secondary: ide1, port 0x170; major=22; hdc is minor=0; hdd is minor=64
> Tertiary: ide2, port 0x1e8; major=33; hde is minor=0; hdf is minor=64
> Quaternary: ide3, port 0x168; major=34; hdg is minor=0; hdh is minor=64
> fifth.. ide4, usually PCI, probed
> sixth.. ide5, usually PCI, probed

For UDMA/66, the only controller I know of is the
Promise one. From the Ultra-DMA Mini-Howto:

> 5.2 Promise Ultra66
>
> This is essentially the same as the Ultra33 with
> support for the new UDMA mode 4 66 MB/sec transfer
> speed. Unfortunately it is not yet supported by
> 2.2.x
>
> There is a patch for 2.0.x and 2.2.x kernels
> availabe at
> http://www.dyer.vanderbilt.edu/server/udma/, and
> support is included in the 2.3.x development
> kernel series at least as of 2.3.3.
>
> However to get far enough to patch or upgrade the
> kernel you'll have to pull the same dirty tricks
> as for the Ultra33 as in the section above.

You mail also want to check out the linux raid
mailing list
http://linuxwww.db.erau.edu/mail_archives/.

Good luck! Please post your results to the mailing
list and/or comp.os.linux.hardware.

Joel Auslander
[e-mail]