測試寫入的速度
$ time dd if=/dev/zero of=testfile bs=10M count=100 100+0 records in 100+0 records out 1048576000 bytes (1.0 GB) copied, 2.18135 s, 481 MB/s real 0m2.207s user 0m0.003s sys 0m0.948s
測試讀取的速度
$ time dd if=testfile of=/dev/null bs=10M count=100 100+0 records in 100+0 records out 1048576000 bytes (1.0 GB) copied, 0.387938 s, 2.7 GB/s real 0m0.392s user 0m0.000s sys 0m0.393s
