The Philips DDC (digital compact cassette) which used a pre-mp3 lossy audio compression, resulting in audible artifacts when the tape was still good and awful glitches and errors once the tape got a bit of wear. Only advantage, decks could playback standard cassette tapes as well. Crap format, luckily it never hit the mainstream market. I don't think they built a boombox and i don't remember any company except Philips making the recorders.
And DAT, digital recording without compression, variable sample rate, long play capability on some recorders, excellent (CD) quality. Too expensive for most of us but a studio standard. Decks and tapes are quite reliable, still lots of them around. No boombox but some walkmans were made. Tapes are also used by tape streamers, you can get them cheap (used).
