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z80 comm/Technology, (sdf.org), 09/13/2018
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It's time for a meta-monologue about something I wrote
today[1]. I have a z80 SBC that I want to use for "online
stuff." In an ideal world, I'd connect my USRobotics modem
to the thing and dial in to a system, which would give me
access to sundry online activities. Voila, problem solved
with just my z80 home computer.
The world, unfortunately, is not my kind of ideal. I have a
100Mb cable modem connection for the whole house, with wifi
of course. Oh, what a burden! First world problems...
Anyway, social/economic issues aside, it's my desire to do
quirky and esoteric things with my computers. One of those
is to get my z80 online in a somewhat "authentic" way if
possible, and without adding to the household budget.
Therefore:
Requirement 1: Use the existing connection to the internet.
Ok, that's fine, I can live with that. I'll be connected via
a serial port, so I could imagine that I was using a modem.
And what does a modem do? It connects you to, and allows you
to use, a remote resource. The only difference, I think,
will be "how remote is the resource?" In the case of a
traditional modem, the remote resource might be in the same
city, or state- an ISP or BBS, for example.
Here's another question: what did the ISP or BBS generally
provide? That's a tough one. The BBS scene was pretty
varied; I think I won't be getting that experience *except*
through telnet/ssh connections to BBSes that are out there
after I find a solution. I'll be getting more of an ISP
experience. In the past, I did have an ISP that provided a
shell account along with the internet... so, I'll pretend
that I'm my own ISP, and I'll provide a *nix shell. That
brings be to:
Requirement 2: This is all pretend fun, treat it that way.
Requirement 3: Provide a basic shell environment with
internet access.
Are you with me so far? Here's the thing that I *don't*
want, so it's clear: I don't want to use my z80 computer as
a dumb terminal to access the full computing power of the
Pi. I can do that already, it's not what I'm aiming for with
this project. Heck, I could just connect my VT100/VT52
terminal directly to the Pi and bypass the z80 SBC
altogether, right? Nuh uh, not what I'm aiming for. What I
*do* want is to feel like or simulate "being online" with
my z80 computer. So:
Requirement 4: Make sure the shell access only provides
internet connectivity, and not access to the
computing resources of the Pi. A limited
shell with telnet and ssh out to the
internet, and nothing more.
Hope that makes sense, but it's a monologue, so it doesn't
matter. In any case, what I think I'll get, what I'm aiming
for here, is the ability to use *truly remote* resources and
opportunities. That's what I view the internet as, roughly
speaking.
Oh, I just thought of another thing:
Requirement 5: Have the ability to download items to the z80
So, maybe I'll need x/y/zmodem programs in addition to
telnet and ssh? Kermit? I'm not entirely sure, but I'll need
to figure that out.
OR... should I basically provide a stub that connects me
directly to SDF? In other words, when I open the serial port
it connects me to a getty (or whatever) on the Pi, which in
turn is configured to automatically provide me with a prompt
to login to SDF instead of a local login prompt. I think
that might feel even more authentic; I wouldn't really be
using the Pi for anything other than a connection to the
internet, as I'd use a modem. I'll add:
Stretch goal: Instead of basic shell, provide a direct
method to login to my remote shell on SDF,
therefore having no access to the local
resources of the pi.
Voila. I have my next z80 SBC related project all lined up!
*NOTE: I realize that most z80's never saw the ppp/slip
tcp/ip stuff that I was used to with my mid-90s computers.
Even the 8088 that I grew up with had an ethernet card at
one point. Perhaps z80 computers were used for BBS access,
time sharing systems, and the like. I'll still consider a
connection to SDF as quite sufficient for what I want.
[1]
gopher://sdf.org:70/0/users/tfurrows/phlog/2018/afn_pcEcosys.txt
