I'm giving some info to someone writing a paper on music & tech. I don't want to give incorrect info. Approx. when did keyboards switch from using waveform synthesis to imitate instruments to using 8-16MB samples? (like the Roland SR-JV80xx series)
You might try synthmuseum.com for information about various products.
The Fairlight (introduced circa 1979) was perhaps the first commercial product using sampled rather than synthesized sounds. (It used RAM, not ROM, however).
E-mu was inspired by the Fairlight and introduced the Emulator in 1981.
See http://synthmuseum.com/emu/index.html for details.
Korg introduced the M1 in 1988. "The M1 was unique in its combination of a keyboard, realistic PCM-ROM-based sounds, drum machine, sequencer and digital multi-effects in a single compact unit. " http://synthmuseum.com/korg/index.html
The E-mu Drumulator was introduced circa 1981, and used actual drum samples. The Linn LM-1 drum machine was introduced in 1980 -- it may be the first commercial sample-based musical instrument.