PDP-11/73 booting!

[Allison]

>
>Subject: Re: PDP-11/73 booting!
>   From: Doc Shipley <doc at mdrconsult.com>
>   Date: Mon, 12 Dec 2005 20:59:26 -0500
>     To: General at mdrconsult.com, "Discussion at mdrconsult.com":On-Topic and Off-Topic
> Posts	<cctalk at classiccmp.org>
>
>Allison wrote:
>
>> 
>> Certainly if you can find a BA23 with the rack kit that would be an ideal 
>> solution just make sure it has the PDP-11 backplane (can have a different
>> one for VAX).  Then you can transfer the modules you have to it and have
>> more usable slots as the backplane is 18 slots (ABAB config).  There's
>> a plus you'll have the distribution board for the in box mounted RX 
>> and RD drives.
>
>   Can you elaborate on this?
>
>   I'm running a PDP-11/53 and a PDP-11/83 in BA23s that originally
>housed MV-IIs.  I never knew there's a difference.

The BA23 came with a microPDP-11 backplane or one for the uVAX-II.
While the differences are small when used with care they are differnt.
For the PDP-11 use the MicroPDP11 backplane is desired as the uVAX 
one has three slots that are CD wired for PMI bussed memory.
the DISK interface and distribution board in the back of the drive 
cavity however are the same.  

So if you have a uPDP-11 ba23 you have the disti board and all you need
is a 50pin to 50pin to connect that to the RQDXn and the from there the 
needed (short) cables to the specific drives.

Allison