如何在c检查/ dev / sda下究竟是什么以及当两个都是USB驱动器时/ dev / sdb下面是什么

I have problem in my c program which is transferring/copying data to/from /dev/sda and /dev/sdb.(open, read, write) Both devices are USB pendrives and their Major number is 8. I have problem in my c program which is transfe