Next | Prev | Up | Top | Contents | Index

EISA-Bus Address Space

The EISA-bus address space is divided into I/O address space and memory address space.

I/O address space provides access to the 4 KB page that references the registers on an EISA card on a slot-specific basis and the registers on an ISA card on an address-range basis.

The EISA memory space supports memory that is configured to respond to the address range starting at 0xa0000. On Indigo2 systems, the EISA memory address range extends 112 MB up to address 0x06ffffff (see Figure 4-1). Once properly mapped by the operating system, this memory space can be directly accessed by the CPU through loads and stores.

Figure 4-1 : Indigo2 Memory Space IRIX release 5.2 and later releases provide a set of procedural interfaces that a device driver must use to allocate and map the EISA I/O address space and memory address space.

The Indigo2 has four peripheral card slots that accept EISA, GIO, or graphics cards. A server can support up to four EISA cards, but then a graphics card cannot be used. CHALLENGE M platforms have four EISA slots available. Graphics cards are available that use one, two, or three slots:


Next | Prev | Up | Top | Contents | Index