Introduction and need help bringing some pdp11's back
cz at alembic.crystel.com
Tue Oct 29 21:14:19 CDT 2019
Ok, first hurdle is down. In reading the RQDX3 Controller Module Users
Guide it shows that for a BA23 the 50 pin cable goes down under the Q
bus chassis then loops straight up into the RQDX3. Which is impossible
to do with a modern (hee hee!) 50 pin SCSI ribbon cable as the cable
keys are set up so that it would not be possible to plug the cable into
the RQDX3 without inverting it (Because DEC likes to sell their cables
with upside-down keys). However 30 seconds with a flush cutting pliers
allowed me to remove the cam/key from the cable connector and plug it
into the RQDX3.
System is now booting up off the floppy. Good step forward. I'll shut it
down for now, and get a XXDP+ floppy from Ebay. That should allow me to
format a Maxtor RD54 drive and get this thing up to steam.
Bit of progress. Thanks all! :-)
On 10/29/2019 9:53 PM, allison via cctalk wrote:
> On 10/29/19 9:34 PM, Nigel Johnson via cctalk wrote:
>> On 29/10/2019 20:37, Chris Zach via cctalk wrote:
>>> The M9058 can plug in to any general slot in Qbus for power and does not
>>>> past interrupt or DMA grant. Bottom/end of the bus is fine.
>>> Interesting, I didn't realize the RQDX series boards didn't use
>>> interrupts or DMA. Does the CPU just poll them endlessly?
>> RQDX1 and 2 did not pass them but used them. (Maybe not NPG) I believe
>> the RQDX3 did, however.
> Ok for the edification of all. The M9058 IS NOT the RQDX3 board,
> It is the breakout board used with The RQDX2 or 3. What the M9058 needs
> power for, it adds additional decodes to address up to 4 RD drives
> or 4 floppies, the total is four if mixed so the usual was 3 RDs and 1
> floppy usually RX50 or later RX33.
> All RQDX3 pass grants, some later version RQDX2s pass grants.
> The RQDX3 with either breakout board can interface RD50 through RD54
> MFM disks and RX50, RX33, as well as RX23 depending on revision level
> and system software.
> The RQDX2 is an earlier quad width and ther eare at least three versions
> (firmware and board revisions) will work with All of the RDs 50 through
> 54 but only RX50 and later RX33.
> How do I know?
> MicroVaxII in BA23
> MicrovaxII/GPX in BA123
> MicroPDP-11 in BA23 pedestal stand
> BA11 PDP-11/23 (with smaller ABCD backplane)
> BA11 PDP11/23B (18 slot backplane)
> BA11 PDP11/73 (18 slot backplane)
> All of winch have RQDX3 or late version RQDX2 (BA11 11/23)
> with the BA23 breakout board or M9058 (standard config is BA123).
> Not all of those are "supported configuration" but the docs
> describe them and the setup is straight forward.
>> Nigel Johnson
>> MSc., MIEEE
>> Amateur Radio, the origin of the open-source concept!
>> You can reach me by voice on Skype: TILBURY2591
>> If time travel ever will be possible, it already is. Ask me again yesterday
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>> Nigel Johnson <nw.johnson at ieee.org>
>> Please consider the environment when deciding if you really need to
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