blk_non_zero$(nW)TEST2: START: blk_non_zero
 $(nW)blk_non_zero$(nW) 512 $(nW)testfile1 o w:0 r:4 r:3 r:2 r:1 r:0 w:0 r:0
512 block size 512 usable blocks 2080567
is zeroed:	0
write     lba 0: {1}
read      lba 4: {5}
read      lba 3: {4}
read      lba 2: {3}
read      lba 1: {2}
read      lba 0: {1}
write     lba 0: {2}
read      lba 0: {2}
blk_non_zero$(nW)TEST2: DONE