IBM RS/6000 - Manual (Page 78)

data. In the case of AIX, the abstraction layer builds the required IPL control block
before the AIX boot image is loaded.
In the first part of this chapter, we will explain the components involved in the boot
process:
Boot record
Firmware
Software ROS
NVRAM
Boot image
Then, we will describe the boot process performed by the firmware, and finally we
will give an introduction to the System Management Services (SMS) programs.
4.1 Boot Record
On microchannel-based RS/6000 systems machines, the entire disk is dedicated to
the AIX operating system. Block 0 of the disk is expected to contain the
boot-record.
Figure 17. Hardfile Layout on Microchannel-Based RS/6000 Systems
The hardfile layout on PCI-based RS/6000 systems is designed to allow
transportable media between various processor types (for example, Intel and
PowerPC 60x) the hardfile layout is similar as now found on a system running DOS
or OS/2. It implements the concept of disk partitions as specified in the PReP
Specification. Following this architecture, the AIX disk image would reside in one of
those partitions, as shown in Figure 18.
Figure 18. Hardfile Layout on PReP Specification
54 Introduction to PCI-Based RS/6000 Servers