ppcopy

Copy files over the parallel port using Linux and DOS and a LapLink cable.

Building

To build everything (both Linux and DOS utilities), type:

make

This builds all four programs:

• par-read and par-write (Linux utilities)
• parread.com and parwrite.com (DOS utilities)

Requirements

• GCC (or compatible C compiler) for Linux utilities
• NASM (Netwide Assembler) for DOS utilities

Build Options

You can build specific targets:

make linux       # Build only Linux programs (par-read, par-write)
make linux-i386  # Build 32-bit statically linked Linux programs (par-read-i386, par-write-i386)
make dos         # Build only DOS programs (parread.com, parwrite.com)

The DOS assembly programs support different debug levels:

make parread.com DEBUG=0   # Minimal size (188 bytes, default)
make parread.com DEBUG=1   # With error messages (287 bytes)
make parread.com DEBUG=2   # Verbose debugging (571 bytes)

make parwrite.com DEBUG=0  # Minimal size (default)
make parwrite.com DEBUG=1  # With error messages
make parwrite.com DEBUG=2  # Verbose debugging

The DEBUG=0 build is optimized for manual entry via the DOS DEBUG utility.

Usage

Usage on Linux

This consists of two utilities: a way to write a file to the parallel port from Linux, and another to read.

First, connect the LapLink cable. Then, on one computer, type:

par-write <file>

Replacing <file> with whatever file you want to copy.

On the other computer type:

par-read > <output>

Replacing <output> with whatever file you want to copy.

The file will be written to <output>

Usage on DOS

There are assembly language versions that you can use for reading and writing on DOS. They consist of two .COM programs: parread.com and parwrite.com. They are optimized to be small so that you can load them via the debug utility if you have no other way of copying files to the DOS machine.

Receiving files on DOS

Connect a LapLink cable between the Linux computer and the DOS machine. Run par-write on the Linux computer, and on the DOS computer run

parread

The output will be placed in C:\parread.out.

Sending files from DOS

parwrite.com can send files from DOS, enabling DOS-to-DOS or DOS-to-Linux transfers without needing a Linux sender. On the DOS computer, run

parwrite <file>

On the receiving end, run par-read on Linux or parread on another DOS machine.

QEMU Device

A QEMU device that emulates a LapLink cable connection between two VMs is included in the qemu-device/ directory. See qemu-device/README.md for integration and usage instructions.

Protocol

See PROTOCOL.md for details on the wire protocol used for transfers.