atacontrol software or hardware raid

[Omer Faruk Sen]

How can I detect if system has Software or hardware raid? Since in manual page:

 The atacontrol command can also be used to create purely software RAID
     arrays in systems that do NOT have a "real" hardware RAID card such as a
     Highpoint or Promise card.  A common scenario is a 1U server such as the
     HP DL320 G4 or G5.  These servers contain a SATA controller that has 2
     channels that can contain 2 disks per channel, but the servers are wired
     to only place a single SATA drive on each channel.

Or how can I find out if the hardware is "real" hardware RAID card?
For example my system has following dmesg output:

ad4: 152627MB <Seagate ST3160815AS 4.AAB> at ata2-master SATA300
ad6: 152627MB <Seagate ST3160815AS 4.AAB> at ata3-master SATA300
ar0: 152625MB <Intel MatrixRAID RAID1> status: READY
ar0: disk0 READY (master) using ad6 at ata3-master
ar0: disk1 READY (mirror) using ad4 at ata2-master

This system is an intel server with S3210SH server board in it. While
installing system I see ad4,ad6 and ar0 as harddrives in sysinstall. I
choose to install ar0.

Additionally as far as I see ar0 is very susceptible to errors since a
single CRC error can break the RAID consistency is that normal?  I
really appreciate those who uses such a kind of RAID1

Regards.