Re: mmap:ing /dev/rsdNc fails with EINVAL on all my attempts&man pages give no hint. Any way around it?

[Todd C. Miller]

Not all devices support mmap.  Only those that define a d_mmap entry
in cdevsw[] will work (see conf.c and conf.h in the kernel).
On OpenBSD, disks can not be mmaped.

 - todd