[HECnet] Raspberry Pi + SIMH VAX?

[Rob Jarratt]

I got my Raspberry Pi a few days ago too. I too have had few problems,
although for some reason the download of libpcap took an extraordinary
amount of time. I have built the 780 emulation, along with two modifications
of my own, difference disk files, and a DMC11 emulation.

I am running the Pi now 24 hours a day as my HECnet router (node VAX780 at
5.8) using the bridge running on a server that I already run 24 hours a day.
The virtual disk files are stored on the server and I use SMB to access them
from the Raspberry Pi, partly because the 8GB SD card I planned to use did
not work and I had to use a 4GB one, partly because I have heard that SD
performance is poor.

I am not as good on unix these days as I used to be, is there an easy way to
get SIMH to start up automatically on booting the Pi?

I like the idea of a cluster of Pis, might get a few more at some point and
try that myself.

Regards

Rob

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-
hecnet at Update.UU.SE] On Behalf Of Mark Benson
Sent: 03 June 2012 22:21
To: hecnet at Update.UU.SE
Subject: Re: [HECnet] Raspberry Pi + SIMH VAX?


On 4 May 2012, at 00:07, Boyanich, Alastair wrote:


Sampsa:

Interesting. Be sure to set up the idle detection in the simh.ini for
your appropriate OS (netbsd/TheoLinux/VMS/Ultrix/etc..) or it'll run
the CPU flat-out all the time and potentially get hot. I'm really
curious to hear how 'hot' the R-Pi's get under load. Mine's still on
order.
Beautiful idea.

I got my Raspsberry Pi Thursday. It runs SimH 3.9.0 flawlessly under the
provided Debian Linux 'squeeze' distribution from a SD Card. The I/O on
the
RPi isn't fantastic from SD Card, it just about manages 5.5MB/s by most
people's benchmarks which is rather slow.

libpcap and screen are installable from the provided arm6l repositories so
no
need for compiling those. Once I did that I just downloaded the source
zip,
unzipped it into a directory and used 'make' to build, just like normal.
Built
fine and runs perfectly.

PDP-11 simulation is plenty snappy enough running RSX-11M Plus 4.2 on a
simulated 11/83 with 2048kW of RAM. I have DECNet 4.0 (Phase IV) working
on there too and it works fine.

VAX KA655X simulation is... sluggish. I'm used to running it on 1.xGHz
x86_64
CPUs (Atom or AMD) with fast hard drives or SATA SSD. The CPU speed
makes it slow but imagine it's as fast or faster than a real late model
VAX. It's
by no means perishingly annoying, it just takes a little thinking between
operations. I think I may be spoilt as I've never used a real VAX.

Overall so far I'm very impressed with the RasPi and it will fulfil the
roles I
need for it. When I get hold of a few more I am going to try and build a
VMS
cluster that uses less than 6W :) I will also have one permanently running
a
PDP-11 (something that I've not managed since I had my Cobalt Qube2
running) RSX-11MP system.

Oh and CPU Idle works just fine in PDP-11 and VMS-VAX simulations. To be
honest even when I compiled all the simulator binaries for SimH (as a
stress
test) and when I was running the SYSGEN in RSX-11M it barely got much
worse temperature-wise than hot to touch a the CPU. On a board that only
uses 300mA with no USB and Ethernet active it hardly has a lot of energy
to
dissipate as heat in the first place!

I'm gonna have a LOT of fun with these :D

--

Mark Benson

http://DECtec.info
Twitter: @DECtecInfo
HECnet: STAR69::MARK

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