ISA Bus

The following sections describe the ISA bus.

ISA Bus Memory and I/O Space

Two address spaces are provided: memory address space and I/O address space. Depending on the device, registers can appear in one or both of these address spaces, and are self-identifying. Table A-3 shows the registers for memory and I/O address spaces in the ISA bus.

Table A-3 ISA Bus Address Space

ISA Space  Name	Address  Size	Data Transfer  Size	Physical Address  Range
Main memory	24	16	0x0-0xffffff
I/O	--	8/16	0x0-0xfff

Hardware Configuration Files

In the Solaris 8 operating environment, the use of hardware configuration files to provide arguments to probe(9E) on IA platforms is highly discouraged, since probes can lead to system hangs and resets. Exact device configuration information is maintained by the booting system and is passed to the probe(9E) function.

Bootable (Realmode) Drivers

A separate realmode driver might need to be developed for the booting system. See the Realmode Drivers white paper in the Driver Development Site at http://soldc.sun.com/developer/support/driver for information on realmode drivers. Hardware configuration files may be needed on some occasions to augment the information provided by the booting system. See driver.conf(4) and isa(4) for further details.