Now ,I am testing the speed of the IDE(ATA) on a PC.

The hard disk had have a File System on it (made under DOS) ,
so , I use :
then write(fd,0x5000000,number) and read(fd,0xa000000,number);
and so on.

The hard is 7200 speed. The data volumeI impletement a time is
about 100MB

The result is : write:4MB/s
read: 3.5MB/s

I think it is impossible, so slowly !