How are drive numbers assigned in Partition Work?

[TeraByte Support]

it's from the BIOS. Typically they make the booted drive HD0. For UEFI the program just assigns the number based on the order UEFI returns the drives available.

[Bob Coleman]

Hi everyone,

I’ve got one internal SSD and a USB-connected external hard drive.
While checking in BIU Partition Work, I noticed something unexpected — the external HDD is listed as Drive 0, while the internal SSD shows up as Drive 1.

Out of curiosity, what determines how these drive numbers are assigned? Is there a specific order or rule that the software follows?

Thanks for any clarification!

I have exactly the same configuration and found this surprising also, but, as you say, it's just curiosity.