You want to store a $500$ MB file into a cluster with $12$ nodes, which are located in four different racks $($three nodes per rack$).$ See Figure $1.$

$1.$ If a data block can store $256$ MB$,$ how many data blocks are needed to split this file?

$2.$ Use a replication factor of $3$ and the write principles discussed earlier to allocate the data blocks into this cluster.