UDP on 1970's micros [was Re: NeXT]

From: Thomas Pfaff <thomas100_at_home.com>
Date: Sun Sep 13 01:20:27 1998

The neat thing about using a PIC chip is that it's external... so
with a little extra logic you can route it through either a parallel
or serial port.

UDP is User Datagram Protocol... it's good enough that you can write
simple clients and servers to transfer data. Many servers can be
switched from TCP to UDP services on any unix machine or a tiny
daemon can be written to do the routing. So you could access a web
server on the net via a TRS-80 this way.

Of course it would be nice to have full TCP/IP available but it's
considerably more work.
There is a stack for the C64. I'd like something that is portable,
a widget that plugs on the back of a variety of early PCs. Something
like a box with a Z180 board, with serial and ethernet on board
would be very nice for a full network implementation.

Ironically the upstart company I helped "startup" does all of this
in a gate level implementation [no processor required] but it's
available only as an embeddable logic core for integration into
things like cellular phones and kids toys.

Anyway, UDP is good enough as long as you do checksums on the data
that comes through. Obviously you couldn't run a web server using
UDP very well. TCP/IP would be more fun because as an exercise you
could host a web server on computers from the 1970's.

Also if you did TCP/IP, IP, ARP and PPP all in software on a 1970's
micro you probably couldn't do a whole lot else in RAM. However, a
dedicated embedded SBC between your
Trs-80 and your Sun Sparcstation could allow your Trs-80 to do quite
a bit and would simplify data transfers to and from the net, etc.
It could be made simple too... type in a small BASIC program to
program your IP address and bootstrap your network connection. It
could be that easy [no floppies required].

I mentioned the PIC controller with UDP first because they are small
and egg-stremely cheap.

Thomas


Begin forwarded message:


  I've heard rumors of IP (not TCP/IP, just IP) being written for the C-64
(along with PPP or SLIP I assume). Apparently, the port only had IP and
ICMP (Internet Control Message Protocol---at the same layer as IP) as
nothing else could fit in 64k. IP isn't that difficult (and uncompressed
SLIP is pretty easy as well). UDP is just a user accessable (under UNIX)
version (more or less) of IP (unreliable datagram protocol, but I
think UDP
stands for User Datagram Protocol, as a datagram protocol is unreliable by
definition if I recall correctly).
Received on Sun Sep 13 1998 - 01:20:27 BST