Well RFC 791 doesn't mention any "link control protocol". Maybe it never
existed. Well modern man's highest acheivement launched in 1983 I see then. I
just can't get over the way IP packets split, find the shortest routes and
recombine at the destination :) amazing. PDPs are certainly mentioned in rfc
791 !
Bill
----- Original Message -----
From: Michael Short
To: SIMH
Sent: Saturday, March 12, 2016 5:36 PM
Subject: Re: [Simh] [SimH] Networking support
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 <[email protected]> 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 <[email protected]>
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
To: Anders Magnusson
Cc: SIMH ; Bob Supnik
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 <[email protected]>
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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