In the qbus realm where many of us spent the waning days of our VAX careers,
the serial cards we dealt with were DZQ11's, DZV11's, and DHQ11's.  The DZQ
was a faithful port of the DZ11 into the qbus and had all its performance
problems.  The DHV was likewise a faithful port of the DHU11 and was bug for
bug compatible -- right up to the point where both would wedged the kernel
under ultrix in exactly the same way and under the exact same conditions.
The DHQ, now there's a beauty for you.  Driver-compatible with the DHU/DHV,
but only a dual (the DHV was a quad), and none of the DHU/DHV bugs.  Eight
ports per unit.  I am using one of these now in an KA655 Ultrix system to be
my "console server" for the rest of my systems.  If god uses asynch, he's
clearly still using a DHQ11.  There's no finer board on any system.

How 'bout them VM bugs, though?