RX50 / RX33 Questions related to PDP-11's - test-drb@ccmp.vtda.org

14 Oct 1998

...
 I'm using the RQDX3 controller as the floppy
controller and the WQESD
(ESDI) controller as the boot device.  When I tell the system to boot from
DUB0 or DUB1 which is the terminalogy that the WQESD controller expects
(figuring that out, i.e. reading the manual took longer than I want to
admit) with a RX50 attached, it will access the floppy drives, this is best
evidenced by my using a cleaning floppy in the drive (made it easy to hear
the drive being accessed).
When I try using a pair of Teac floppies I've converted to RX33's using
information I found on Sunsite I'm not really sure it tries to access them. 
Keep in mind that early RQDX3 revisions don't know how to talk to
RX33's - they're limited to RX50 floppies.  Seeing as how your system
is apparently doing bizarre things with the RX33's, this might be the
case.

What exactly do your "RX33's" do when you try to access them?

What firmware revision is your RQDX3?

...
   Can you use RX50 floppies to boot a
 system with RX33 drives? 
Yes.

...
 Will RT-11 boot off of a floppy drive at CSR 17760334? 
I've tried with
both the Boot disk from my RX50 distribution set, and a RX50 boot disk that
I made using PUTR.  I've a sinking feeling that having two disk controllers
is confusing RT-11. 
To get RT-11 to deal with two DU controllers, you can either:

1.  Do a SYSGEN to create a DU handler that can handle more than one
    DU controller.  With recent enough RT-11's, the same handler
    copes very nicely with multi-port booting.

2.  COPY DU[X].SYS to another name (say, DG[X].SYS), and then SET DG:CSR=nnnnnn
    and SET DG:VECTOR=nnn, where nnnnnn is the CSR and nnn is an unused
    vector in your system.  When you create a bootable floppy which you
    want to be bootable on your second controller, you must lay down the
    DG bootstrap instead of DU, since the DU device points to the wrong
    controller.

The tradeoffs between the above two methods are documented in the
RT-11 _System Generation Guide_ and the RT-11 _Device Handlers Manual_.
Method #2 above is easily the quickest, and will probably do just fine
for your purposes.  (Though a RT-11 system with extended-unit multiport
DU handler is a beautiful sight!)

...
 Is it possible to create a Bootable TK50 with RT-11
that can be used to do
the install? 
Look for the file MUB.COM on your distribution:

Again, it will depend on which version of RT-11 you're running whether
MUB.COM is MU-bootability is present.

-- 
 Tim Shoppa                        Email: shoppa(a)trailing-edge.com
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