There are three common types of RAID implementations: "hardware"(high-end RAID cards), BIOS-level software(low-end RAID cards) and system daemon-level software(such as the md daemon on Linux).
The RAID support that comes built-in with your motherboard is *probably* software RAID implemented in your system BIOS. Most small RAID cards have their functionality implemented in on-card BIOS that gets loaded when the system boots. As with system-software RAID setups like md, these RAID setups consume your system CPU and RAM as they churn to perform the calculations associated with your RAID configuration, including things like ECC and parity calculations.
All of this is best-known as "software" RAID.
The funky thing? "Hardware" RAID is also done in software, albeit software that executes on a dedicated processor on your RAID card. (As opposed to your system CPU.) You upgrade this software whenever you upgrade the firmware on the card.
So here's what I'd like to see...An Open Source hardware RAID card. All it would amount to is a multi-port SATA controller connected to an onboard CPU, passing data back to the host operating system via the PCIe bus.
The firmware would be built by, well, I dunno. The folks who like md, but don't like running it on their core system. The folks who want to play around with experimental RAID configurations and ideas. The folks who want to try putting LVM into "hardware." There are plenty of possibilities.
Put a fallback firmware set on the card, in case of flash upgrade failure, to avoid bricking the thing.
I'd hit that.
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