About a small town’s worth of people pointed me to this on Mastodon, so here it goes:
In an IMAX theater, the m130’s job is to control the quick turn reel unit, or QTRU for short. (For many years, it appears, a non-emulated m130 sat holstered in most theaters.) The QTRU’s job is to control the platters, which are those large horizontal shelves where all of a film’s many reels are stitched together, stored, and then quickly spun out to and from the projector. The IMAX 1570 projector moves film at a little under six feet per second, so it’s all happening really fast.
The m130 is apparently crucial to keeping the thing humming — “PALM PILOT MUST BE ON ALL THE TIME,” reads a notice above an image of a different m130 that has since been passed around the internet — but doesn’t often need to be used. “I’ve never had to interact with the Palm Pilot,” says one person familiar with the technology. “It’s really just a status screen.” Its job is to keep the QTRU moving at a consistent speed and to help keep the film’s video in sync with its audio.
This doesn’t surprise me one bit. In environments like these, if something works, and has been working reliably for decades, there’s really no reason to change any of it. This application is probably quite simple, but since there’s only a very small number of theaters out there even capable of showing 70mm film, and it doesn’t look like it’s a format on the up and up.