# 2023/10/04

## On Retrocomputing

I've been spending a bunch of time working on some Z80 systems, mostly
CP/M systems. I need to spend some more time learning about the
differences between CP/M 2.2 ZSystem. One of these systems, an SC131 [1]
is connected via Tailscale to the internet over SSH. This works something
like this:

  [SC131] <= FTDI => [Pi consrv] <= [Tailscale]

It's kind of useful being able to hack on CP/M stuff remotely; however,
there some issues downloading new files to it. I think it's related to
latency between the SSH host and the serial link because even pasting
in data seems to get hung up pretty quick. If I plug it in directly, I'm
able to use XMODEM just fine. I wrote a Pascal version of DUMP.COM and
a reverse version (UNDUMP) [2] that should work on the RC2014s and the
SC131.

I learned some new things about CP/M in writing these tools. In
particular, CP/M doesn't support the FileSize, FilePos, Seek, and Flush
procedures don't work on CP/M (c.f. page 267 of the Turbo Pascal 3.0
manual). Speaking of the Turbo Pascal 3.0 manual, I found a copy on eBay
that I've ordered. There's a lot of things I want to learn, such as how
to write CP/M programs specifically, as well as writing my own Z80
monitor.

## BBSes

I've been trying to set up a BBS. I found mystic BBS [3], currently
running on a Raspberry Pi. However, I haven't gotten the message board
or file uploads working, which is 95% of what I want a BBS for. I think
what I want are four core functions:

  + a message board
  + mailboxes
  + file uploads
  + chat functionality

Mailboxes seem like a subset of message boards: you could post a message
where the board is an individual user. There's a part of me that wants to
run this on a retrocomputer. File uploads should probably support XMODEM
or ZMODEM, and there needs to be some basic association on the files so
the owner can delete or upload. Maybe directory-based permissions?

The answer is that I probably need to write my own.

## Modem

I would like to be able to connect to BBSes from my CP/M systems. I have
the RC2014 WiFi module [4], but it works the wrong way: it allows you
to connect remotely over telnet to your RC2014. I tried getting Zimodem
[5] working, but it wouldn't build. I think the answer is obviously to
write my own.

## kge

A while ago, I wrote my own text editor; I'd like to build a GUI version
using Dear ImGui. It needs to run on Windows and Linux, and it would be
nice if it could build on MacOS too.

So far, I haven't gotten it running yet. I've been trying with Conan [6],
but I can't find all the dependencies. I'm currently trying to build it
with support for GLEW/GLFW. The other option is trying to set up some
sort of conditional build.

Anyways, that's a brain dump for now.

[1] https://smallcomputercentral.com/sc131-z180-pocket-computer/
[2] https://git.wntrmute.dev/kyle/kcpmtk
[3] https://www.mysticbbs.com/
[4] https://rc2014.co.uk/modules/esp8266-wifi-module/
[5] https://github.com/bozimmerman/Zimodem
[6] https://conan.io/