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

14 Oct 1998

...
 To get RT-11 to deal with two DU controllers, you can
either:

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 problem with this technique is that the handler name is built into
the driver, which is used by XM to locate the extended memory region
used to store data (and other code), and the two handlers would still
have the same name.  You would need to SIPP the new handler and search
for all references to the name 'DU' (search for ;rDU) to 'DG' (;rDG).

					Megan Gentry
					Former RT-11 Developer

+--------------------------------+-------------------------------------+
| Megan Gentry, EMT/B, PP-ASEL   | Internet (work): gentry!zk3.dec.com |
| Unix Support Engineering Group |          (home):  mbg!world.std.com |
| Compaq Computer Corporation    | addresses need '@' in place of '!'  |
| 110 Spitbrook Rd. ZK03-2/T43   | URL:     http://world.std.com/~mbg/ | 
| Nashua, NH 03062               | "pdp-11 programmer - some assembler |
| (603) 884 1055                 |  required." - mbg                   |
+--------------------------------+-------------------------------------+