MR Piggy

<img src="README.md.d/mrpiggy.jpg" width="33%" align="right">

An fork of MS Kermit with the build system ported to GNU make, jwasm, and Open Watcom C so that no proprietary software is needed to compile. The resulting executable is 16-bit (8086) and can run on original IBM PC hardware or in an emulator such as dosbox.

This has been tested and works on genuine hardware as a replacement for MS Kermit.

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Compilation

If you have jwasm and owcc installed (see below), then you can create a DOS executable of kermit.exe by simply running 'make' on your GNU/Linux box.

Prerequisites

Compilation requires the jwasm assembler and Open Watcom C compiler (owcc). GNU Make syntax is used in the Makefile. UPX is used to compress kermit.exe from 300KB to 150KB.

Jwasm

I used tuxxi's masm-unix which made compiling jwasm on GNU/Linux straight forward.

<ul><details><summary>Cut and paste this into a command line to compile and install jwasm:</summary>

    sudo apt install build-essential cmake
    git clone http://github.com/tuxxi/masm-unix
    cd masm_unix/src/JWasm
    cmake .  &&  make  &&  sudo cp -p jwasm /usr/local/bin/

</details></ul>

Open Watcom C Compiler

Watcom Install

The Open Watcom v2 source code is overly large to download and git times out, so I had to install a prebuilt copy.

<ul><details> <summary>Cut and paste these commands to install the Open Watcom v2 C compiler:</summary>

cd
mkdir ow2
cd ow2
R=https://github.com/open-watcom/open-watcom-v2/releases
wget -O ow2.zip "$R"/download/Current-build/open-watcom-2_0-c-linux-x64
unzip ow2.zip
rm -r ow2.zip binnt binp binw rdos rh 
mv binl64 bin
cd bin
chmod +x $(file * | grep ELF | cut -f1 -d:)
mv vi weevil

<details><summary>32-bit binaries</summary>

Binaries are in binl instead of binl64; rename it to just bin. If you don't have a binl directory, try changing x64 to x86 in the wget line.

cd
mkdir ow2
cd ow2
R=https://github.com/open-watcom/open-watcom-v2/releases
wget -O ow2.zip "$R"/download/Current-build/open-watcom-2_0-c-linux-x86
unzip ow2.zip
rm -r ow2.zip binnt binp binw rdos rh 
mv binl bin
cd bin
chmod +x $(file * | grep ELF | cut -f1 -d:)
mv vi weevil

</details> <details><summary>About weevil</summary>

Note that we've renamed the Watcom editor to weevil because calling it vi on a UNIX system is silly. It is clearly the love-child of Microsoft EDIT and ed plus it's a bit buggy (try Ctrl+C), thus "weevil".

</details> </details></ul>

Watcom Compiler Setup and Usage

The Makefile already sets up everything needed for compilation, presuming Watcom is installed in $HOME/ow2. To compile just run:

make

However, if you want to use Watcom by hand, read on.

<ul><details>

To use the Watcom C compiler, you'll first need to setup the compilation environment like so:

export WATCOM=${HOME}/ow2
export PATH+=:${WATCOM}/bin
export INCLUDE=${WATCOM}/h

You can run that at the command line or add it to a Makefile. To compile a program, you use the owcc command, like so:

owcc  -bdos  -mcmodel=s  -o myprog.exe  myprog.c

You can then execute the .exe file in dosbox to test it out.

</details></ul>

UPX

UPX can be installed with apt install upx-ucl, for Debian GNU/Linux.

Uncompressed, the file kermit.exe takes up 300 KB, which leaves no room for documentation or DOS on a 360 KB floppy disk. So, by default the Makefile uses upx to compress the executable down to 150 KB. On an IBM PC (8088 4.77MHz) compression adds a twelve second pause before running and saves six seconds of floppy disk access. Of course, the pause will be shorter for faster CPUs.

Or, if you have a large, fast drive, use the uncompressed executable, kermit-uncompressed.exe.

Supplementary files

• mskermit.ini configuration file loaded on startup. This example file has been modified to default to using TELNET over a TCP/IP network instead of a serial connection. (This requires a packet driver for the network card has already been loaded.)

• emacs.ini for Emacs key bindings, currently loaded by mskermit.ini. This can take dozens of seconds to load on a floppy based system.

Todo

• [x] Get it to compile under GNU/Linux

• [x] Test the .EXE on an IBM PC

• [x] Reduce file size so it is more useful on retro-PCs (currently it is 322 KiB

  • [X] Look into runtime DOS executable compressors. Do any exist that are Free Software?
    • Surprisingly, Yes!
    • Running upx on KERMIT.EXE cuts the size in half to 152 KB.
    • Noticeably slower start up time in emulation with DOSBOX.
  • [X] Measure compressed start time on actual PC hardware. It might be faster than uncompressed due to floppy access. (Nope! Saved six seconds of I/O and added twelve of CPU.)

• [ ] Bundle with FreeDOS as a bootable 360KB disk image.

• [ ] Maybe include the numerous miscellaneous supplementary files that came with the MS Kermit 3.14 distribution.

• [ ] Configure Makefile to automatically add builddate to symboldefs.h.

• [ ] Is there any benefit to using mTCP's network code instead of Kermit's?

• [ ] Look into ways to reduce filesize that do not impact start up time

  <details>
  • Simple Methods
    • [ ] Compiler, linker flags.
    • [ ] Investigate: why is Open Watcom executable 50 KB larger than the one created by Microsoft tools in 1999. Is it Watcom's standard library?
    • [ ] Check how Open Watcom's PACKDATA works.
      • Kermit 3.14 notes state that 40KB was saved by using PACKDATA option of LINK.EXE. That option exists in Open Watcom but produces no savings in file size.
      • WARNING! I had thought PACKDATA was safe to experiment with, but I realized that since stack checking is disabled, a smaller segment size might cause pointers to wrap around!
      • [ ] What is the max size of the data structures in Kermit?
  • Complex Methods
    • [ ] Conditional compilation
      • [ ] Add "Lite" versions (no NET, no GRAPHICS, neither) to Makefile.
      • [X] What existing subsystems does CHECK command identify?
        • IF: ???
        • Network: How does this differ from TCP?
        • TCP/IP:
        • Graphics: Tek4010 & Sixel
        • Terminal: Terminal emulation. no_terminal implies no_graphics.
        • (nls_portuguese: Missing from check but exists as ifdef.)
      • [ ] Identify other large subsystems
        • [ ] serial port? script interpreter? H19 and other terms?
        • [ ] weird networks like IPX
      • [ ] Wrap them in #ifdef, same as Lite.
    • [ ] Analyze algorithms and datastructures to trim for size.
    • [ ] How large is Kermit's TCP/IP, DHCP, and DNS implementation? Is mTCP smaller?
  </details>