'>>' will cause O_APPEND to be specified as flags when opening "/dev/sda". I'm pretty sure this flag is ignored on block devices as it's obviously useless.

'>>' will cause O_APPEND to be specified as flags when opening "/dev/sda". I'm pretty sure this flag is ignored on block devices as it's obviously useless. fd = open("/dev/sda", O_WRONLY|O_CREAT|O_NOCTTY|O_APPEND, 0644); pos = lseek(fd, 0, SEEK_CUR); -> pos = 0 http://hastebin.com/abuhiwivoz.pl http://hastebin.com/abuhiwivoz.pl # tmp sudo ./open_sda Current position after open: 0 Current position after seek to end: 128035676160