In the early days of computer CD-ROM drives, aside from SCSI interfaces, there were a number of proprietary interfaces developed by individual manufacturers. This was exemplified by PC sound cards such as this Sound Blaster 16, which included three different connectors for CD-ROM drives: (source: https://commons.wikimedia.org/wiki/File:KL_Creative_Labs_Soundblaster_16_CT2230.jpg)
On the left of the board, we see headers for a Creative / Panasonic drive, a Mitsumi drive, and also a Sony drive.
As the IDE/ATAPI standard became established, later cards were shipped with a single 'IDE' header (e.g. the Sound Blaster 32), and was eventually left off altogether when motherboards started carrying dual IDE controllers as standard.
My question is as follows:
How did these early interfaces differ from each other, and from the eventual ATAPI standard that followed?