So I found a 9-track reel-to-reel tape drive on eBay that looked like it was in working and beautiful condition. It’s a Kennedy 9800 with the reels arranged horizontally so it doesn’t take up half an equipment rack. I’d like to use it with a PDP-8/e system emulated via SimH running on a Beaglebone Black, so I’ll need to build a controller for it.
The Beaglebone Black has two independent, real-time CPU cores called PRUs that could totally control this tape drive. Developing for those seems a pretty specialized process so I’m opting to build a USB controller that presents a SCSI Sequential Access Device, using SCSI Stream Commands.