root@192.168.0.11:/mnt# make diotest1
cc -DSRC_DIRECT -o diotest1 diotest.c
root@192.168.0.11:/mnt# make diotest2
cc -o diotest2 diotest.c

[Creating srcdata with /dev/urandam]
root@192.168.0.11:/mnt#  dd if=/dev/urandom of=srcdata-urandam bs=32k count=1024
1024+0 records in
1024+0 records out
root@192.168.0.11:/mnt#  hdparm -d 0 /dev/hda

/dev/hda:
 setting using_dma to 0 (off)
 using_dma    =  0 (off)
root@192.168.0.11:/mnt# ./diotest1 srcdata-urandam dstdata
sfd ret = 3
dfd ret = 4
ret = -1
root@192.168.0.11:/mnt# cmp srcdata-urandam dstdata
srcdata-urandam dstdata differ: char 2210, line 8
<The above means have difference between "srcdata-urandam" and "dstdata">