"Aaron J. Grier" <agrier@poofy.goof.com> writes:

> Just curious, but why does DEQNA come before the DHV11?  It
> generates more interrupts?

Sunsite is your friend!  For lots of interesting information, start with
<URL:http://sunsite.unc.edu/pub/academic/computer-science/history/pdp-11/>
and browse around.  For this particular bit of information, check out the
"micronotes", and especially micronote 41 (near the bottom of the list),
which and includes the following recommendation (and the reason for it):

|     Table 1 lists the order in which devices should be placed in the
|     Q-bus.  Please refer to the detailed information about each device
|     that follows the table.
|
|                               Table 1
|                               -------
|
|     1.  TSV05 9 track magtape controller
|     2.  DMV11 Microprocessor controlled DECnet communications interface
|     3.  TQK25 Controller for 8 inch magtape drive
|     4.  DHV11 Microprocessor controlled communications multiplexor
|     5.  DEQNA Ethernet controller
|     6.  TQK50 Controller for single spindle cartridge magtape
|     7.  RLV12 Controller for 14 inch RL series disk drives
|     8.  RQDX3 Controller for 5 1/4 inch RD/RX drives
|     9.  KDA50 Controller for 14 inch RA series disk drives
|    10.  RQC25 Controller for 8 inch RC25 series disk drives
|    11.  RQDX2 Controller for 5 1/4 inch RD/RX drives
|    12.  DRV11-WA General purpose 22 bit DMA interface

-tih
-- 
Popularity is the hallmark of mediocrity.  --Niles Crane, "Frasier"