On 2017-04-05 17:24, Theo de Raadt wrote:
"ls -l /dev/rsd0c; ls -l /dev/sd0c" shows that sd0c is a block device
and rsd0c is a character device, and mmap's man page says that
"character special files" are OK.
The manual pages will never list all restrictions.
/dev/sd* delivers ~120MB/sec globally, whereas /dev/rsd* delivers
~575MB/sec, sustainedly in my tests, likely due to lots of the IO
subsystem being bypassed on /dev/rsd* access, as discussed in the misc@
ML thread with David Gwyne.
So presently higher-speed access is restricted to read()/write() -
noted.
