[Simh] [SimH] Networking support

Sat Mar 12 17:36:05 EST 2016

On the history of networks, there was also a network called BITNET which
was mainly used
by educational institutions using mainframes. Started around 1981, it was
originally based on
the bisync protocol and was a store-and-forward system. At it peak it had
about 500 organizations
and about 3000 nodes. Toward the end, it morphed into BITNET II using TCP.

On Sat, Mar 12, 2016 at 3:31 PM, Clem Cole <clemc at ccc.com> wrote:

> Bill,
>
> You probably need to date things a little and get a some perspective of
> where a few of us are coming.   Just to set a few lines in the sand.  While
> 3Mb/s "xerox" ethernet has been around for about 5 years, the
> DEC/Intel/Xerox Ethernet 10Mb/s spec was published Sep 30, 1980.   Per RFC
> 801, Arpanet was not officially schedule to switch from the old NCP to IP
> until Jan 1, 1983 (although a number of folks like me had been working with
> what would become IP/TCP for 3-4 years before that).  But "networking" as
> we think of it today, had been around for over 10-15 years before that -
> i.e. long before the rise of the PC.
>
> Most large (mini/mainframe) manufacturer have their own networking.
>  Consider DEC's VMS, the original IP/TCP implementation was written by me
> and my co-workers at Tektronix at the time (1979-80).  DEC wants us to use
> DECnet.   We also have CDC, UNIX boxes and even a IBM mainframe.   We
> needed something that could span the OSses.  It was easier for us to write
> our own implementation because what we wanted was a network that spanned
> our companies use, not one manufacturer.
>
> Moreover "Metcalfe's Law" is also very important (the value of a network
> is proportional to the exponent of the number of the things connected to
> it).  So ... each manufacturer had their own scheme - both HW and SW.   The
> widest "general" system was the Arpanet "IMP" system that DoD paid to have
> interfaced to a number of different systems; although as has been discussed
> PDP-10's, 11s and eventually Vaxen were a large number of the systems on
> that network.  So in fact, that was the most valuable network because it
> had the most systems connected to it that had cool things that could
> used/shared.
>
> Actually, the largest reaching network at the time was the Unix UUCP
> network, which allowed email and file transfer (al biet a tad slowly).
> There were thousands of sites on it.  In fact the UUCP site "ccc" pre-dates
> ccc.com being registered to me because in those days people could not
> register a domain name.  But "usenet" could not do things like telnet and
> was a good bit less formal that the ARPAnet or the Internet.
>
> Roll forward and think of PC's.   Please remember with the PC's
> pre-ethernet  too were often "networked" most often with ARC-net HW (75 ohm
> coax - very cheap), running either Netware or LAN-Manager.   Like, DECNet
> and the systems from the mini's and mainframes, it allowed PC to send files
> around, share printers, send email etc.   But like all other proprietary
> systems, it was closed so it's not talk to your Vaxen or UNIX systems etc.
> The size of these networks tended to be the size of your office during
> Word/Excel et al.   Which was fine for a lot of people... but....   it's a
> little like having a local walkie-talkie that is not connected to the
> larger network and you can talk to a few people.  When you finally realize
> you need to talk to someone outside your firm, you note how limited it it.
>
> So... between the US Gov paying for the SW to be written to support a # of
> OS's they cared about, the rise of UNIX, and MetCalfe's Law, IP became the
> protocol and ethernet became the HW that "stuck" - i.e. the rise of the
> Internet.
>
> Now consider that by the time the PC and BBS system that PC's used come on
> the scene you have a quite a different view.  Also, BBS's were really not a
> network in the same way the mini's and mainframes worked.  A person that
> knew a phone number and had an account to call a remote system.   But this
> is quite different from how the DECNet, SNA, Arpanet, etc (or for that
> matter UUCP) worked.
>
>
>
>
> Back to your question...  if we want a simulation system to support
> networking in the way most of us think of it, we need two things.   First
> the HW needs to emulate some know HW that was developed and released by the
> manufacturer.  Second, you need the OS support for same.
>
> Frankly, it is probably not worth investing a lot of effort into writing
> the HW emulation unless we have the SW to drive it.   And frankly, you need
> to think how you will use it.  Modulo Johnny and the cool folks running
> HECnet (a large world wide network running DECnet over the Internet), you
> probably will want to have Internet functionality to be able to access the
> systems.
>
> The good news is that a number of folks developed implementations for
> almost most of the major OS implementations and many of the manufacturers
> eventually picked them up (DEC would eventually take the Tek/CMU IP
> implementation in house).
>
> The bad news is I fear except for a few cases where the manufacturer
> picked it up and made a product, some of those stacks (like the HP-1000 and
> HP-3000 stacks from BBN) have been lost.   If someone has those it would be
> cool, but I have not seen those bits since the early 1980s.
>
> Clem
>
>
>
>
>
> On Sat, Mar 12, 2016 at 2:36 PM, Bill Cunningham <billcun at suddenlink.net>
> wrote:
>
>> What I meant was that I remember on early PCs using an rs232-c line for
>> using the old BBSes and compuserve before it was an ISP. 10 cents a minute.
>> I had several modems 300, 1200 and 2400 baud modems.
>>
>>     These even older machines may have had hookups within a company. Even
>> one building connecting 5 or so machines. Serial would've worked fine. And
>> was what was used. I was thinking with maybe 4-5 PDP8s a company would use
>> some kind of networking. Perhaps not back then. I was only aware of pdp11
>> and vax being "network possible". I guess I was wrong.
>>
>> Bill
>>
>>
>> ----- Original Message -----
>> *From:* Clem Cole <clemc at ccc.com>
>> *To:* Anders Magnusson <ragge at ludd.ltu.se>
>> *Cc:* SIMH <simh at trailing-edge.com> ; Bob Supnik <bob at supnik.org>
>> *Sent:* Saturday, March 12, 2016 2:24 PM
>> *Subject:* Re: [Simh] [SimH] Networking support
>>
>>
>> On Sat, Mar 12, 2016 at 12:25 PM, Anders Magnusson <ragge at ludd.ltu.se>
>> wrote:
>>
>>> DG-UX or MV/UX?
>>>
>> Which was the rewrite of System V ?? i.e. System V cmd system, but
>> internally developed System V SMP kernel -- I want to say DG-UX maybe; but
>> I'd been a long time and many beers ago - I've forgotten the name.   I
>> remember it was a very clean UNIX implementation.   Nice locking structure,
>> easy to debug, etc...
>>
>> Locus was working on different projects with Ultrix, Tru64, VMS, AIX,
>> SunOS, Solaris, HP-UX, Apollo, DG's UX, some work for Pr1me, ISC's 386/ix,
>> Intel's 386 port, SVR4 for the AT&T/UI guys, and Intel's Paragon at the
>> same time.  At one point, I had the OS release schedules for HP, DEC and
>> Sun all pasted on the wall behind my desk.  I used to say LCC got to see
>> everyone's dirty laundry in those days.  As I said, I do remember the DG
>> Unix re-implementation was very easy to work on (I will not say which one
>> we cursed the most).
>>
>>
>>
>>
>>> The DG ethernet card has a 82586 on board.
>>>
>> As I said, many beers ago. I'm undoubtedly mixed up a couple of the
>> systems, since we had so many we worked with in those days.  I remember the
>> AMD chip was a lot easier to program than the Intel device. That said, I
>> suspect that I have the docs on the Intel chips somewhere, but it sounds
>> like others have the DG docs which are going to be better for simh purposes.
>>
>> Clem
>>
>>
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