September 12, 2001 IBUS 4 pmax

### NAME

ibus - pmax internal I/O space driver

### SYNOPSIS

ibus0 at mainbus0 ibus0 at tc? slot ? offset ?

### DESCRIPTION

ibus is a virtual device corresponding to the pmax internal I/O space found on DEC 2100, 3100, 5100 and 5000/200 systems.

Internal I/O space spans the pmax physical address space, and is mapped permanently in the kernel virtual space at the very early time of the kernel startup procedure.

ibus driver manages the internal I/O space of pmax.

- Address range management to avoid confliction of address space of which devices probe by touching hardware port is difficult.

- Interrupt vector management.

- bus_space(9) and bus_dma(9) implementation.

- Other utility functions.

ibus is always required to run the NetBSD kernel.

### SEE ALSO

intro(4), bus_dma(9), bus_space(9)