ACPI Bochs dsdt.dsl unexpected io Definition

[sebihepp]

Dear OSdev forum,

I wanted to know if there is an FDC (Floppy Driver Controller) existing in the system, before writing a driver for it. So I thought it must be in the ACPI tables. Using the wiki I found the DSDT and looked through bochs DSDT for an example.

I stumbled across something strange. There is one IO description for 0x3F2 with size 4 and one for 0x3F7 - the status registers A and B are missing.

Where is the error in my head?

Best regards
Sebi

[Octocontrabass]

Some floppy disk controllers don't have status registers A and B, and Bochs is capable of emulating at least one such controller.

I think the default floppy disk controller in Bochs does have those status registers, though. That's probably a mistake in the DSDT. (I wonder if it's a common mistake on real hardware...)

[sebihepp]

Thank you very much. I thought they were needed. But after having a look into the documentation again, you are right: They are completely optional.