For interest "IBM PC Memory Shift software utility 1984" returned no useful hits for the software described that way early on the article.

As a 1980s developer I'm going to guess that's meant to reference Borland's Sidekick which was a seismic revelation for the time.

* https://en.wikipedia.org/wiki/Borland_Sidekick

Or was Memory Shift an actual TSR swapper I just never encountered?