Re: Re: Re: RAID bus controller: Promise Technology, Inc. PDC20376 (FastTrak376)(rev02)
On Mon, Feb 28, 2005 at 09:17:46PM -0700, sarge netinst debian-pure64 wrote:
> There is no such thing as a TOY_raid module. Use a bios_disk module.
>
> The GNU Parted manual says:
>
> 3.1 5. The operating system may or may not use the BIOS to do normal
> file system access (Windows usually does, Linux or BSD do not).
>
> So Windows goes to the BIOS to find the disk. The disk c: in DOS for
> example could be an array of disks like /dev/hde, /dev/hdf, /dev/sda and
> /dev/sdb and the DOS user would never know. The sata_promise doesn't
> know those disks are in an array so the module should ask the BIOS or
> there should be a way to tell the sata_promise those disks are used in
> an array not individually. (If the sata_promise wanted to do RAID.)
>
> The bios_disk module asks the BIOS how the disks are configured and
> doesn't care if that is an array or just individual disks because the
> BIOS does all the work. That should be as good as a TOY_raid module.
>
> Maybe someday the on-board RAID controllers will be good enough to use.
> Then RAID support might be needed.
With the current trend of "win*" devices with more and more loading
firmware by driver, and off loading processing to the CPU all in the name
of cutting manufacturing costs (and wasting the end users expensive cpu)
I doubt we are going to get real raid chips on the mainboard ever.
people even seem willing to buy sound cards that don't off load any of
the signal processing while spending lots of money on the video card to
get higher frame rates in their games (while the sound card just ate 10%
of the cpu and framerate because it is cheap junk).
As long as the average computer buyer is clueless about computers (and
why shouldn't they be, it's a rather complicated piece of electronics),
there will continue to be companies making cheap junk that has impresive
looking specs for less money than something better.
> Does anybody use any of the RAID features on any motherboard for Linux?
I prefer to use something I can trust, like md raid in linux. At least
then I get the source code to the drivers for my raid. If I have to
waste cpu cycles running a software raid, at least I want to know how it
works, and I also suspect the linux software raid is more cpu efficient
than whatever the proprietary software raid makers have put in their
bios.
Len Sorensen
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