Pro-Pack

Pro-Pack, more commonly known as RNC, is a file compression utility used by several commercial games. It was developed by Rob Northen, who also produced the Rob Northen copylock copy protection scheme.

The compression utility was made available for the Amiga and IBM PC. It can compress Amiga Hunk, MS-DOS EXE, Atari ST TOS and Atari Lynx executables, as well as raw data files. Decompression routines written in assembly language were provided for 680x0 processors (Amiga, Atari ST, Megadrive), 80x86 (IBM PC), 65c816 (SNES) and 65C02 (Atari Lynx)

Identification
ProPacked data files begin with ASCII "", followed by an 0x01 or 0x02 byte to indicate the compression method used.

Format documentation

 * Reverse-engineered data format from Sega Retro

Software

 * RNC_ProPack.lha - includes the original compressor for IBM PC and Amiga, all the decompression routines mentioned above, plus a MIPS R4300 version for the Nintendo 64 and a Z80 version for the GameBoy
 * Pro-Pack compressor and decompressor written in C
 * Ancient

Sample files

 * https://telparia.com/fileFormatSamples/archive/rnc/