Short: Data transfer PET/C64/VIC20 <-> Amiga Author: rhialto@mbfys.kun.nl (Olaf Seibert), Marko Mäkelä 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.