AHCI and SATA spec

[Klakap]

I found that on AHCI page we have some structures from SATA spec 3.0 But SATA specification 3.0 is not freely available. Is it legal to have these things on wiki?

[Octocontrabass]

The SATA 1.0 specification seems to be freely available. Have the structures changed since then?

[nexos]

The SATA 1.0 specification seems to be freely available. Have the structures changed since then?

I found that doc about 5 minutes ago, and that made my day! I think for a hobby OS relying on that is OK, as I am sure that SATA implementation are probably backwards compatible with SATA 1.

Also, one could just look at Linux. That would be legal. Or you could just look at Haiku if you're concerned about licensing problems with the GPL 2.

[Octocontrabass]

I am sure that SATA implementation are probably backwards compatible with SATA 1.

There were quite a few mistakes in the original SATA 1.0 specification that were corrected in later versions. You might be able to find archived copies of the errata from before the SATA 2.5 specification was published in early 2006.

[nexos]

Actually, the SATA spec is quite reasonably priced at $25 dollars. It might be a good investment depending on how serious you are.
My OS should support most storage devices. We have ATA and ACS free drafts. There are SCSI and SAS free drafts. AHCI is free, SATA is only $25. NVMe is free. I'd say that's pretty good!

[Klakap]

The SATA 1.0 specification seems to be freely available. Have the structures changed since then?

Thank you! I think that because SATA-IO selling specifications 2.5+, it mean that they do not care about spec 1.0, so it is free.

[Ethin]

I'm pretty sure that posgin source code for the figures in the SATA spec is perfectly legal. After all, it wouldn't make sense for them to bar that -- everything that can interface with SATA/AHCI has those definitions (or similar) and they'd have to go after *every* use of it, which would be impossible. I'd say that its similar to the NVMe specifications: those are free, but so long as you don't directly quote the document and claim that your work incorporating the spec is by NVM express, its perfectly legal -- because, again, open-source software contains those same definitions, and outlawing that would be nonsensical and unenforceable. But if there's a lawyer on here who can verify that, that'd be nice. But I'm pretty sure its legal because you can find those definitions in tons of OSS software. Same for the PCI specs. Just don't directly link to the paid specs.

[nexos]

I agree with what @Ethin said. If the code were illegal, then Linux would be long gone.

[Ethin]

Bumping this topic because I'd just like to add another reason to avoid SATA 1.0: the changes that've occurred in SATA 2.5+. The SATA 3.5A specification describes all the changes in Ch. 1. NCQ priority and unload is one of the features, as well as alterations to the BIST activate FIS, fast fail, and a few other things too.