IBM RS/6000 - Manual (Page 99)

Chapter 5. AIX Version 4.1.4 Support
AIX Version 4.1.4 is the first supported operating system on the PCI-based
RS/6000 servers, E20 and F30. These machines can be installed from a standard
AIX Version 4.1.4, or later, installation CD-ROM or over the network.
AIX Version 4.1.4 provides support for four features which are specific to or
different from the PCI-based RS/6000 servers when compared with
microchannel-based RS/6000 systems:
Support for a soft "key-switch" function
System dump support
mksysb support
ISA adapter configuration support
The first three features are discussed in detail in this chapter. ISA, together with
PCI adapter configuration support information, can be found in Chapter 6, “Adapter
and Device Configuration on PCI-Based RS/6000 Servers” on page 99.
This chapter also covers Graphics support for the PCI-based RS/6000 servers.
5.1 Electronic Key-Switch Function
One of the main differences between the traditional microchannel-based RS/6000
systems and the current range of PCI-based RS/6000 systems is the omission of a
physical key. On all microchannel-based RS/6000 systems, there is a physical key
which can be in one of three positions:
Normal
Service
Secure
Although the E20 and F30 do not have this physical key, they have an electronic
key-switch instead. Currently, this provides the ability to boot the machine in
Normal or Service modes. The electronic key-switch is a logical key-switch,
separate from a physical one, that the platform firmware knows about. Its state is
communicated from the firmware to AIX through a residual data environment
variable. Currently, only the firmware can set the electronic key switch.
5.1.1 Boot-Device Order List
When an E20 or F30 has passed through the firmware boot-up stage, it is then
required to boot an operating system. To do this, the machine ha
s to know
which device it should try and boot from. To enable this to happen, the E20 and
F30 both use the Boot Device Order List (Boot List). There are two of these on the
E20 and F30. The first list is the default one, and it has four entries:
1. Diskette drive (not supported in AIX Version 4)
2. Internal CD-ROM drive
3. Internal hard disk
4. Network adapter
 Copyright IBM Corp. 1996 75