[Simh] Questions on SIMH VAX

[Zane H. Healy]

I'm actually thinking about buying a D510 motherboard, not a Netbook.  The
Intel motherboard includes a Gigabit NIC, and a PCI slot.  I'd probably put
an Intel 10/100 NIC in the PCI slot specifically for SIMH.  With a couple
Seagate 500GB SATA drives, Optical Drive, and 2-4GB RAM I think I'd have a
fairly usable 'low-power' system.  Though the drives and 2nd NIC would
definitely bump up the power it would pull.

I would hope to see performance somewhere between my MicroVAX III and
VAXstation 4000/vlc.

Actually that brings up another question, how RAM intensive is SIMH?  If I
can do this under OpenBSD, I know it's very light on its memory usage.

Zane



On Wed, 9 Jun 2010, Hittner, David T (IS) wrote:

> Be careful if you are using the wireless NIC of the netbook. Read the
> SIMH FAQ about wireless Ethernet, particularly the info about Decnet
> Phase IV compatibility, and be prepared to adjust cluster timeouts as
> required; significant delays can occur during wireless disruptions.
>
> As to VUPs, the netbook can't be worse than a VAX-780 :-)
>
> Dave
>
>> -----Original Message-----
>> From: simh-bounces at trailing-edge.com [mailto:simh-bounces at trailing-
>> edge.com] On Behalf Of Zane H. Healy
>> Sent: Wednesday, June 09, 2010 4:56 PM
>> To: Marc Chametzky
>> Cc: simh at trailing-edge.com
>> Subject: Re: [Simh] Questions on SIMH VAX
>>
>>
>>
>> On Wed, 9 Jun 2010, Marc Chametzky wrote:
>>
>>> I can give some input from my experience on a few of these things...
>>
>> Thank you, it tends to indicate what I am considering is doable.
>>
>>>> Does anyone happen to know what kind of performance this would
> give?
>>>> How many VUPS would such a setup offer?
>>>
>>> I don't know how it would perform on your system as I'm not familiar
>> with the
>>> performance characteristics of the Atom processor. On my SIMH setup,
>> which is
>>> a virtualized Linux system running on an ESXi host using an AMD
>> Phenom II X3
>>> 710 processor (limited to 2 GHz on a single processor), I get 13
> VUPs
>> (using
>>> SRI's PT_VAX.EXE).
>>
>> I've no idea what that CPU is, as I'm not familiar with AMD products,
>> but a
>> quick google would seem to indicate that's more than 3x the CPU power.
>> Of
>> course the Atom isn't designed for this sort of workload.  Even if it
>> isn't
>> practical to run WASD, I could still do pretty much everything else on
>> SIMH.
>>
>>> I will note that I got better idle handling once I started running
>> DECnet. I
>>> think that SIMH dealt better when there was some occasional activity
>> (such as
>>> handling network packets) rather than a truly idle system.
>>
>> It would definitely be running DECnet Phase IV, as I'd want to be able
>> to
>> talk to my PDP-11's, and have it on HECnet.
>>
>>>> I assume that Volume Shadowing is supported, so that I can place
>> disk
>>>> images
>>>> on seperate physical hard drives and turn on shadowing?
>>>
>>> That should work just fine. There might be an issue with SIMH
> working
>>> properly if one of its virtual drive volumes becoming unavailable,
>> though, so
>>> an advantage of volume shadowing (system reliability) probably goes
>> away.
>>
>> My thought was to have redundancy should I loose a physical HD.  Which
>> is
>> why I use Volume Shadowing on my Alpha.
>>
>>>>  What about
>>>> clustering with real physical VMS systems if I desire it?
>>>
>>> I've done it in the past using SIMH VAX clustered with a hardware
>> Alpha box.
>>> It worked just fine.
>>
>> Perfect, as if I were to use it, I'd want to be able to cluster with a
>> MicroVAX III and an Alpha at a minimum.
>>
>>>> How large of
>>>> virtual disks does SIMH support?
>>>
>>> Big. :-) Using a command like "set rqb0 rauser=N" in vax.ini, I'm
>> able to use
>>> large drives including one that's 15 GB. I did need to tweak my
>> sources in
>>> order to get large volumes working properly at some point in the
> past
>> (an
>>> issue with the large file APIs), but that was some time ago and I
>> don't
>>> recall whether it was still needed with the current sources.
>>
>> My Alpha currently runs with 3 36GB drives, and 1 50GB drive.  Though
> I
>> could trim down the required space.
>>
>> Zane
>>
>>
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>