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From: mcculley@alien.enet.dec.com
Newsgroups: comp.sys.dec
Subject: Re: MicroVax hardware compatibility
Message-ID: <15464@shlump.nac.dec.com>
Date: 19 Sep 90 19:50:58 GMT
Sender: newsdaemon@shlump.nac.dec.com
Organization: Digital Equipment Corporation
Lines: 26


In article <1990Aug24.012018.485@spcvxb.spc.edu>, terry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr) writes...
>In article <12927@hydra.gatech.EDU>, bb16@prism.gatech.EDU (Scott Bostater) writes:
>> I have some software written for VMS version 4.6 that makes use of a PDP-11
>> backward compatibility mode.  I want to run the software on a microvax.  Is
>> this backward compatibility mode going to shoot me in the foot?  
> 
>  The correct answer is "it depends". If your software did it the documented
>way and used the RSX AME (Application Migration Executive), it will run on
>the MicroVAX II *if* the II has the AME installed.
> [...]
>  Also, earlier versions of the AME did not supply a software emulator for
>the CPUs that didn't have compatibility mode. The current version (V2.4) does
>provide a software emulator.
> 

Also, if you really need to run the code on the MicroVAX with better
performance than the software emulator will give, you might look into the
CoProcessor/RSX (CP/RSX) product.  This uses the KXJ-11 board to provide a
PDP-11 coprocessor in Q-bus MicroVAX systems, with an RSX system running on the
coprocessor and a modified AME environment on the VAX side.  The KXJ-11 is a
J-11 CPU with some memory and a limited set of on-board I/O facilities, without
bus arbitration logic.  This provides a heterogenous multiprocessing
environment with CP/RSX software to handle the rather unusual hardware
configuration.
hardware