SINGLE MODE
None-RAID: (Single Mode) Computer will show up as two independent drives. This function can be use if only one HDD is installed. Or, two different brands or capacities of HDDs are installed.

RAID O - SPANNING MODE
Two HDDs will show up as one large single drive.
Spanning is an array (not RAID) that is written
sequentially across two drives.

RAID O - STRIPPING MODE
Two HDDs will show up as one large single drive but speed performance will boost up. The two HDDs will write Data in “column” effect. This form of array splits each piece of Data across both HDDs in segments. Data are store between first HDD and second HDD. While the HDD is stripe in writing, the next head of next HDD is move to next track to write.
The Data is writing without any form of data-checking. Once one HDD is damage and all Data can be lost.

RAID 1 - MIRRORING MODE
Using this mode will require 2 identical HDDs; meaning they must be the same capacity, brand and model number. Under RAID1, it will create an extra copy (or mirror) set of data to second drive. The backup data are more important for safe keeping and the available data only show up in one large single drive. This is useful when first HDD fail and it can be replaced by second set of identical data instantly.