Jerome Fine replies:
 Once done, the SET command values are held in the
 DU.SYS device driver file.  You do NOT need to
 do the SET commands each time.  Probably not
 recommended in any case. 
Ahaaa... Is that saved in DU.SYS when you issue the commands, then?
Makes sense.  I'll try it when I get home.
  Assuming you are booting from an RL02, then the
 DU.SYS device driver my be LOADed for a bit faster
 response after the first usage.  In addition, I
 strongly suggest you use RT11FB rather than RT11SJ
 unless the added size of the RT11FB monitor has
 a serious impact on the program which you run. 
Well, the idea is to load TSX-Plus over it, which requires the SJ monitor.
  In addition, it would be helpful to know the full
 version number of the RT-11 version which you are
 using.  Based on the above SET commands, it must
 be at least V05.03 or RT-11 which was released
 in 1985.  There are certain features which later
 versions of RT-11 have that you may wish to be
 aware of.  the RT-11 command:
 SHOW  CONFIG
 will provide the information, as will the banner
 when RT-11 first boots. 
On bootup, and in SHOW CONFIG, the version is given as 5.00.
  Finally, I strongly recommend against the SET
 values which have been suggested since they
 impact very negatively with regard to booting
 RT-11.  You will not lose anything with a 
Ok, why is that?
  different combination of SET parameters, but
 you will gain with respect to what drives
 can be booted, in particular from a cold start. 
In this instance I want to boot from a "clean" install of RT-11 from DL0,
but eventually I will be booting from DU0.
  The exact nature of which disk drives are being
 used will also help.  I suspect an RD53 and an
 RX50, but please confirm.  Most novice RT-11 
OK, this is where it gets tricky.  I'm not totally sure how to identify
the ST506 drives fitted to the machine.  One is a full-height 5.25" drive,
with (seemingly) about 65,000 blocks on each partition.  The other is
half-height, with considerably less on each partition - one is around
40,000 blocks, one is around 16,000 blocks (if I remember correctly - I'm
not actually near the machine right now to check).  The smaller drive is
made by Fujitsu, may be something like M224XAS ?  The label is rather hard
to read.
The other drives are an RL02 (I have two but lack the cable that links the
two drives) and an RX02.
Gordon.