The Amiga offered these features before most other competing home computer platforms though the Macintosh which had been introduced a year earlier had similar capabilities. The Amiga's main rival, the Atari ST, sourced the Yamaha YM2149 Programmable Sound Generator (PSG). Compared to the in-house designed Amiga sound engine, the PSG could only handle 1 channel of sampled sound, and needed the computer's CPU to process the data for it. This made it impractical for game development use until 1989 with the release of the Atari STE which used DMA techniques to play back PCM samples at up to 50 kHz. The ST, however, remained relevant as it was equipped with a MIDI controller and external ports. It became the choice of by many professional musicians as a MIDI programming device.