System Information Record (HINFO)(转)
http://www.zytrax.com/books/dns/ch8/hinfo.html
Allows definition of the Hardware type and Operating System (OS) in use at a host. For security reasons these records are rarely used on public servers. If a space exists in the field it must be enclosed in quotes. Single space between CPU and OS parameters.
name ttl class rr Hardware OS IN HINFO PC-Intel-700mhz "Redhat Linux 7.1"
name can be empty!