This uses byte level striping. i.e Instead of striping the blocks across the disks, it stripes the bits across the disks.


Whereas RAID 0 uses block striping. Are there so many bytes to a block? Do bytes even make up a block?

Using this article


It makes more sense to compare RAID 3 and RAID 4, since the two only differ in the stripe size (they both use a dedicated parity drive). Note that RAID 2 does essentially the same thing, except on a bit level, but at least Wikipedia claims that RAID 2 is not used in practice (albeit not entirely surprisingly that claim is tagged "citation needed"; it's usually much easier to provide references for positive than negative claims, so this ought to be taken with a grain of salt).

RAID 0, in contrast, employs no parity at all but is striping only.

In RAID 4, each drive holds a multi-byte block (presumably the block -- stripe -- size is configurable on the controller because there are tradeoffs between block size and performance).

In RAID 3, the block size is effectively fixed at 1 byte.

Blocks are simply groups of a (largely arbitrary) number of bytes. Everything on storage can always be thought of as bits and bytes (particularly if we define a byte as a contiguous set of 8 bits, with alignment if you want to get fancy), so yes, by that definition, bytes are what makes up blocks.


Read under "History"

Early in the computing industry, the term "block" was loosely used to refer to a small chunk of data. Later the term referring to the data area was replaced by sector, and block became associated with the data packets that are passed in various sizes by different types of data streams. For example, the Unix program dd allows one to set the block size to be used during execution with the parameter bs=bytes. This specifies the size of the chunks of data as delivered by dd, and does not affect the size of the sectors used by the medium to which the data is stored.

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