A P P E N D I X G

Sun Ultra 250 UPA/PCI System

This appendix describes information that is different in this PCI-bus-based system than that in an Sbus-based Sun system.

---

Banner Command Output

The output of the banner command appears as follows, indicating that it is a PCI-based system.

---

Generic Names

Note that the output of the show-devs command shows some PCI- based nodes. PCI-based systems use generic names for devices. That is, the on-board network is named "network", and internal disks are named "diskn", with n representing the scsi target number for that disk, ("disk" with no number refers to "disk0"). Plug in PCI cards with their own FCode PROM may or may not be using generic names.

For details on generic names, see Recommended Practices available on the homepage for the Open Firmware Working Group at: http://playground.sun.com

---

SCSI Internal Busses

For Ultra 250 systems, there are two internal SCSI busses. The device "scsi" refers to the internal SCSI I/O bus for internal disk.

The following shows the output of a devalias command on a Sun Ultra 250 UPA/PCI system.

---

.properties for a PCI Device

When you look at properties for a device node of a PCI device, you will see a few properties that are unique to PCI devices and a few properties that have a different format than that of a SBus device. For example, the output of .properties for a PCI device:

The following example shows generic names for devices under /pci@1f,4000/scsi@3 :

---

.speed Command

The command .speed shows the speed for both processors and busses attached to the system, as follows:

---

Probing of Slots For PCI Busses

The Sun Ultra 250 UPA/PCI system has four PCI plug-in slots, distributed across a single PCI bus. Probing of slots for those busses is controlled by the following two NVRAM configuration variables:

TABLE G-1 NVRAM Configuration Variables

Variable Name	Default Value	Description
pci0-probe-list	3 ,2, 4, 5	Controls probe order of plug-in devices under pcio
pci-slot-skip-list	none	Controls skipping of PCI plug-in slots

pci0-probe-list specifies the device probe order on the "B" bus of the 1F PCI Controller. Device 3 is the motherboard 876 UltraSCSI bus (internal disks), while devices 2, 4, and 5 are open 33MHz 32-bit slots for plug-in cards.

pci-slot-skip-list is a list (0 to 3) of PCI slots that should not be probed. The values "0" to "3" correspond to the backpanel PCI slots, from bottom to top.

The Ultra 250 systems provide 4 PCI plug-in slots, numbered from 0 to 3, bottom-to-top (accessible and labeled from the back of the system).:

TABLE G-2 PCI Plug-in Slots

PCI Slot	PCI Bus PCI Device	Width		Speed
3	pci0	/pci@1f,2000/xxx@1	32 bit	33 MHz
2	pci0	/pci@1f,4000/xxx@2	32 bit	33 MHz
1	pci0	/pci@1f,4000/xxx@4	32 bit	33 MHz
0	pci0	/pci@1f,4000/xxx@5	32 bit	33MHz

where the xxx will correspond to the particular PCI card plugged into that slot. For example, plugging an 875/glm SCSI controller card into slot 0 will yield /pci@1f,4000/scsi@5 , while plugging an 876 dual-SCSI card into slot 3 will yield two separate "devices" /pci@1f,2000/scsi@1 and /pci@1f,2000/scsi@1,1 .

---

Probe SCSI Command

The following is a sample output of the probe-scsi command showing the two internal SCSI busses.