11/93 Rebuild - SCSI HD now boots RT11

Rod Smallwood rodsmallwood52 at btinternet.com
Fri May 31 14:27:48 CDT 2019

On 31/05/2019 19:40, allison via cctalk wrote:
> On 05/31/2019 02:04 PM, Rod Smallwood via cctalk wrote:
>> Hi
>>      Well I now have a bootable SCSI drive on my 11/93. Its not RSTS/E
>> (yet) but it is RT 11 and reliable.
>> Its a bit baseline but it runs.
>> So next up was to see if we could get the RQDX3 to co-exist with the
>> SCSI controller.
>> I switched the base address to 160336 and it does not stop the SCSI
>> drive booting as DU0.
>> Had the RQDX3 been on the normal base address I think you would get the
>> HD as DU0 and the two halves of an RX50 as the next two drives.
>> But what happens to the RX50's when you move the RQDX3 to 160336 ?
>> Rod
> Under RT-11 you have to do a SET CSR and sometimes Vector when you move
> a device off the default.  Its how I could have two DD (tu58) on teo
> serial ports.  Same for RX02, RL02, with RQDX3 (with RD52 and RX33)
> where the RQDX was set to a nonstandard address.
> As I remember the CMD controller is nominally the same as RQDX3 for the
> same address. so likely RQDX at the secondary address (see the manual)
> will be treated well if not use the set utility.  It  only comes to mind
> as I had two RQDX3s in one machine to make RD52 to RD52 copies at one
> point.  Also my BA123 uVAX-II has both CMD SCSI controller (Rz56 x2) and
> RQDX3 for RD52 wher the RD52 was the swap and page disk (QD540s are fast
> but only 31mb) and by having independent channels helped with system
> performance.
> RSTS/E the conventions for non standard device addresses are different
> but there is a mechanism for addressing that.  I've not used that.
> Any of the PDP11 unix again there is a way but the process varies with
> version and is unknown to me.  I tried once to get V^ to talk to more
> than RL02.
> In the end first make sure you using the suggested secondary controller
> address.  Then use the OS dependent tools for installing additional drives.
> Allison

    OK lets see if I can understand whats going on.

1. The CQD sits at the normal 17772150 base address
2. RQDX3 is at the alternate 17760334 base address.
3. The map function in the 11/93 monitor sees both
4. The SCSI drive boots RT11 with the RQDX3 in place.
5. So if I connect an RX50 through the cable splitter as normal then what device(s) is(are) the RX50



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