You feeling ancient thinking back about Pak, lharc, arj and bimodem makes me feel really ancient. I remember dialing the BBS on the phone and then sticking the handset in the acoustic coupler of my Novation CAT which was connected to the LNW System Expansion attached to my TRS-80 Model 1.

You and me both --- I remember stumbling across .ARJ files on abandonware sites at the tail-end of the '90s. Even then, they were something of a curio; ZIP was dominant format, and RAR was gathering pace.

Me too. I still remember the joy of being able to use ARJ in MS-DOS to split archives across multiple floppies.

Which had the feature before PkZip, if memory does not trick me.

Or my friends on the Amiga world exchanging LHA files.