I have this same question. When learning about RAID, they always talk about what happens if a drive fails - but they never talk about what happens if the storage device itself fails.
This excerpt from the Wikipedia article on RAID even makes it murkier:
The disk formats on different RAID controllers are not necessarily compatible, so that it may not be possible to read a RAID on different hardware. Consequently a non-disk hardware failure may require using identical hardware, or a data backup, to recover the data. Software RAID however, such as implemented in the Linux kernel, alleviates this concern, as the setup is not hardware dependent, but runs on ordinary disk controllers. Additionally, Software RAID1 disks (and some hardware RAID1 disks, for example Silicon Image 5744) can be read like normal disks, so no RAID system is required to retrieve the data. Data recovery firms typically have a very hard time recovering data from RAID drives, with the exception of RAID1 drives with conventional data structure.
I'm not that experienced with this, but when I think of software RAID, I'm thinking about how Windows NT/2000 Server did software RAID [which I don't recall anyone ever actually doing this].
I assume with the RAID 1 device I can just take one or both drives and put them in another RAID 1 device as long as the new device can read the same file format NTFS, FAT32, EXT, etc. I could even throw one of the drives in an external hard drive case lying around. This is because there is no parity information involved.
But what about the RAID 5 disks? Can I just take the disks and put them into another RAID 5 device made by another company? I assume I just couldn't take one of the hard drives and throw it in an external hard drive case because a file could be spread across all the disks and I would need data from all the disks. Is the information written on RAID 5 disks can only be seen by that particular storage device itself?