N* Horizon IRQs? Who used them?

[atod]

In reading through some of the N* Horizon technical documents, I saw that the MB has interrupts. It also has the ability to set and clear them. They are for the Real-Time Clock, Serial Ports and Parallel Ports.

Does anyone know if N* compatible CP/M BIOS (Lifeboat?) or NS DOS ever made use of the interrupts? I.e. for background printing or serial transfers? Or perhaps for some sort of periodic ISR?

Just wondering...

Thanks