from Hacker News

How did it come that SATA HDD use ATA while SATA CD drives use SCSI as protocol?

by curling_grad on 2/2/23, 6:28 PM with 5 comments

• by wtallis on 2/2/23, 9:47 PM

  Wow, there are a lot of bad explanations in that thread. A lot of it seems to stem from people not making the distinction between SCSI commands and lower-level transports, many of which also have SCSI in their names. But that seems to be pretty common in storage, where the separation of layers isn't as clear as on the Internet.

• by simne on 2/4/23, 8:31 PM

  This is because SCSI is harder to implement, but SCSI is more flexible, and ATA was not flexible enough to support first CD drives.

  So with first "civilian" CD drives, appear few proprietary interfaces and some used sort of SCSI.

  Than just made decision, to save resources, make hybrid, using ATA electronics, but partially SCSI logic/software.

• by mdmglr on 2/3/23, 2:13 AM

  > SATA HDDs nor CD drives talk any AHCI.

  I bought a used HP EliteDesk Mini G1 off eBay to replace a Raspberry Pi for a project. It requires a SATA m.2 which needs an AHCI controller on-board. Very difficult to find.