The BOSS JS-5 JamStation is a device that provides digital instrument accompaniments that can be programmed for various styles and 128 instruments.
Here's an example of a song I recorded with it. It's Unit 7, a classic Wes Montgomery tune. It's an MP3, about 4.4M. I recorded this on a Zoom 4-track digital recorder. First I recorded the JamStation track to the Zoom, then overdubbed the guitar track.