How do I calculate the parity bit? In a RAID 3 odd parity with 5 disks. How do I get the parity bit?
The answer was
But I want to know how is this calculated?
How do I calculate the parity bit? In a RAID 3 odd parity with 5 disks. How do I get the parity bit? The answer was But I want to know how is this calculated? 

closed as off topic by Jason Berg, EEAA, gWaldo, Iain, MDMarra Nov 19 '11 at 22:14Questions on Server Fault are expected to relate to server, networking, or related infrastructure administration within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here. If this question can be reworded to fit the rules in the help center, please edit the question. 


"Odd parity" means the sum of all the its is odd. This is the same as saying the number of 1 bits is odd. So if the number of one bits is odd, the parity bit must be 0 to keep it that way. If it's even, the parity bit must be 1 to make it odd. 


The parity is calculated via a logical "exclusiveor" operation, XOR. It results in true ( The catch with oddparity is that it's reversed  if the XOR operation results in a So, in the examples above, the second row:
In odd parity, flip the result and that's the result bit; The reason that this is interesting and useful? Let's say disk 2 is lost, and you need to figure out what was in it.
Using the parity, data from a lost disk can be reconstructed with the data from the parity disk plus all of the other disks  this is the reason that this type of RAID group can tolerate the loss of any one disk, but will fail if a second disk fails. 

