Jerome Fine replies: It is really difficult to say why you are getting a crash at 134606. It may be because of the "BAD" RQDX3, but I just don't know and really don't have a clue. I do have one suggestion. Why not have 2 MSCP device drivers? I know that might seem a bit silly when you don't really need the extra partitions (or do you - I thought that the you were using large ESDI drives on the Viking QDT). One point I agree with is that when you are using DEC MSCP device drivers that can't even do a software boot (Sorry Megan - I just don't understand why DEC would leave out ONE instruction in the secondary boot program that is written into block zero) of non-zero partitions, you have used DU0: and DU1: with their respective UNITs and PART=0 both times which allows either to be hardware booted. I suggest instead: RQDX3,2,1 (which ever you use that actually works) = 172150/154 Viking QDT = 160334/150 WQESD = 160354/144 (not that you will actually set the VECTOR) Then place the hard drives on the Viking QDT controller on a device driver called VI: (I used to call my Sigma device driver SI:) and keep the DU: device driver just for the RX50. BUT, don't forget that a simple copy of DU(X).SYS to VI(X).SYS is not sufficient. There are also a number of locations that must modified: (a) SET VI: CSR=160334 SET VI: VECTOR=150 (b) wherever DU appears as .RAD50, change it to VI You can set up the VI(X).SYS on the hard drives along with the DU(X).SYS, but you will have some trouble in switching to the above suggested CSR/VECTOR settings unless you can get a bootable RX50 on the RQDX3,2,1 If you can, and you can produce the necessary VI(X).SYS, on the RX50 (you will also need SIPP to make the (b) changes, and you can get everything to work correctly with the new hardware and software set-up, then copy the VI(X).SYS to the hard drives on the Viking controller. Then as a test, boot the hard drives on the Viking controller as a software boot using: "BOOT VI0:RT11FB" That will be a software boot for those hard drives and will test that everything works. If possible, have the hard drives under WRITE PROTECT (and first make a backup of the RX50 and WRITE PROTECT it so you can't lose it). Once you get that far, the final step (without WP) is to: "COPY/BOOT VI0:RT11FB.SYS VI0:" either from the hard drive itself or from the RX50 (the latter might be a bit safer). After that, the WQESD (I presume you are using a dual 11/73 M8192 without hardware BOOT ROMs) should allow you to directly boot the Viking hard drives if you specify the correct controller: "B DUB1" if I remember the syntax. If you need help setting up the VI(X).SYS, please ask. If you rarely use the RX50 (I only use the RX50 to transfer stuff to and from the PC using PUTR from John Wilson), then you need not load DU: in any case. The above stuff was done from memory and I may have omitted minor points and been mistaken on others. But, I have successfully run the following MSCP device drivers: DU(X).SYS = 172150/154 RQDX2 with RD53/RX50 QR(X).SYS = 172140/144 RQDX3 Q=dual VR(X).SYS = 172130/134 RQDX2,1 V=quad,2nd HI(X).SYS = 160334/130 Hitachi ESDI drives SE(X).SYS = 160434/140 Seagate ESDI drives all at once and been able to boot from all of them. Finally, if anyone is interested (so far no one has been and at this point it would be a while before I could respond), I can supply a DU(X).SYS for V5.4G and prior which will boot non-zero partitions. They are fun to use, but probably not really worth the effort. But at this point, there is only fun left - so go for it. I think that Tim has also modified the code so it can be Y2K compliant. When I fixed the software for a different version, I found that the year in the TOY rolled over Cmp #99.,Year ;Branch if 20th century Bhis $10 ; is present Add #100.,Year ;Switch to 21st century 10$: But I would check just in case for your model. Sincerely yours, Jerome Fine