Short:        Data transfer PET/C64/VIC20 <-> Amiga
Author:       rhialto@mbfys.kun.nl (Olaf Seibert), Marko Mäkelä <Marko.Makela@HUT.FI>
Uploader:     rhialto mbfys kun nl (Olaf Seibert)
Architecture: m68k-amigaos


This document describes the prlink utility, a program package that
lets you to transfer data over a parallel connection between a
Commodore 8-bit computer and a bigger system (Amiga or PC).

The utility is based on a daemon, or a memory resident IRQ handler
wedge running in the Commodore end of the cable.  You always issue the
link commands from the other side (Amiga or PC).  This implementation
saves you from needing a server process on the bigger computer, which
is very important for MS-DOS users.

Currently daemons are available for the Commodore PET series (3032 and
8032/4032), the Vic-20, C64 and C128 computers.  The Commodore plus/4
may be supported in the near future.  There are compilation options
that support the Commodore REU (RAM Expansion Unit), even
simultaneously with an Action Replay cartridge installed, and some
internal memory expansions on the C64 and the C128.

The client programs are written so that they compile on Amiga and on
Linux with the GNU utilities, and on MS-DOS with Visual C++.  The
programs were originally written for Linux.  The Linux and MS-DOS
versions use machine language optimized transfer routines.  Also the
Amiga version is partially manually optimized in 68000 machine language.

The idea of the transfer utility package is that a daemon runs on the
Commodore side in an interrupt routine, without affecting the computer's
performance.  It checks if the other side wants to send any command,
and executes possible commands.  The protocol includes commands for
memory transfers and for starting a machine language routine or a BASIC
program.  The latter two commands deinstall the daemon for maximum
compatibility.