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From: jonathan@comp.vuw.ac.nz (Jonathan)
Newsgroups: comp.sys.dec
Subject: Re: MicroVAX support for RL02
Summary: RLV12 yes, but RLV11?
Message-ID: <1990Sep08.100922.6323@comp.vuw.ac.nz>
Date: 8 Sep 90 10:09:22 GMT
References: <330.26db7121@dragon.uucp> <33151@cc.usu.edu>
Sender: news@comp.vuw.ac.nz (News Admin)
Organization: Comp Sci, Victoria University, Wellington, New Zealand.
Lines: 38

In article <33151@cc.usu.edu> SLSW2@cc.usu.edu (Roger Ivie) writes:
>In article <330.26db7121@dragon.uucp>, cts@dragon.uucp (Charles T. Smith, Jr.) writes:
>> Does anyone know if the RL211 and RL02 drives are supported by the MicroVAX
>> II?
>> 
>
> [Positive answer]
>
>Of course, this was back before VMS used all 22 bits worth of QBUS mapping.
>If you hook an RL02 up these days, you should make certain that it's the
>new, one board, 22 bit controller instead of the old two board 18 bit
>controller.
>

The 22-bit addressing is indeeld necessary  for recent versions of
VMS. Is it possible to use the old two-board controller for 4.3bsd,
or for old versions of VMS that don't need 22-bit addressing?

The 18-bit two-board controller (RLV11?) must be in two adjacent Qbus
slots that are wired for the ``CD'' scheme, rather than normal Qbus.
The only such slots in a normal Microvax-11 backplane are the two
slots immediately after the CPU board[1], in which the CD slots are
``reserved for memory expansion''.  Installing this controller
mandates removing any additional memory from a Microvax-II, leaving
only the 1Mbyte on the CPU board.

Assuming one's sofware will run in 1 Mbyte physical memory, and does
not use 22-bit addressing, can anyone confirm that an RLV11 works in a
microvax-11?

[1]  DEC documentation variously says that these two slots implement
CD interconnect in the right two "fingers", and an otherwise
undescribed Microvax-II  memory expansion bus. 
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