Alignment value and block size
On the AIX, Linux and Solaris operating systems, an alignment value of 1 is equivalent to a block size of 512 bytes. On the HP-UX operating system, it is equivalent to a block size of 1024 bytes.
The block size on HP-UX is different from that on other supported platforms. Output from commands such as vxdisk and vxprint looks different on HP-UX for the same disk group if the -b option is not specified.