HP-UX Reference (11i v2 03/08) - 1M System Administration Commands N-Z (vol 4)
p
pdc(1M) pdc(1M)
NAME
pdc - processor-dependent code (firmware)
DESCRIPTION
pdc is the firmware that implements all processor-dependent functionality, including initialization and
self-test of the processor. Upon completion, it loads and transfers control to the initial system loader
(isl(1M)). Firmware behavior varies somewhat, depending on the hardware series as described below.
Series 800 Behavior
To load isl from an external medium, pdc must know the particular device on which isl resides. Typically
the device is identified by the Primary Boot Path that is maintained by pdc in Stable Storage. A path
specification is a series of decimal numbers each suffixed by ’/’, indicating bus converters, followed by a
series of decimal numbers separated by ’.’, indicating the various card and slot numbers and addresses.
The first number, not specifying a bus converter, is the
MID-BUS module number (that is, slot number
times four) and followed by the
CIO slot number. If the
CIO slot contains a terminal card, the next
number is the port number, which must be zero for the console.
When the processor is reset after initialization and self-test complete, pdc reads the Console Path from
Stable Storage, and attempts to initialize the console device. If the initialization fails, pdc attempts to
find and initialize a console device. Algorithms used to find a console device are model-dependent. pdc
then announces the Primary Boot, Alternate Boot, and Console Paths.
If autoboot (see isl(1M)) is enabled, pdc provides a 10-second delay, during which time the operator can
override the autoboot sequence by typing any character on the console. If the operator does not interrupt
this process, pdc initializes and reads isl from the Primary Boot Path. On models that support
autosearch, if this path is not valid and autosearch (see isl(1M)) is enabled, pdc then searches through
the
MID-BUS modules and CIO slots to find a bootable medium. Currently, autosearch is only imple-
mented on the model 825.
If the autoboot sequence is unsuccessful, overridden by the operator, or not enabled in the first place, pdc
interactively prompts the operator for the Boot Path to use. Any required path components that are not
supplied default to zero.
The Primary Boot, Alternate Boot, and Console Paths as well as autoboot and autosearch enable can be
modified via isl.
Series 700 Behavior
To load isl from an external medium, pdc must know the particular device on which isl resides. Typically
the device is identified by the Primary Boot Path that is maintained by pdc in Stable Storage. A path
specification is an
I/O subsystem mnemonic that varies according to hardware model.
When the processor is reset after initialization and self-test complete, pdc reads the Console Path from
Stable Storage, and attempts to initialize the console device. If the initialization fails, pdc attempts to
find and initialize a console device. Algorithms used to find a console device vary according to hardware
model.
If autoboot and autosearch (see isl(1M)) are enabled, pdc waits for approximately 10 seconds during
which time the operator can override the autoboot sequence pressing and holding the
ESC (escape) key on
the console.
The system then begins a search for potentially bootable devices. If allowed to complete, a list of poten-
tially bootable devices is displayed, labeled with abbreviated path identifiers (P0, P1, etc). A simple
menu is then displayed where the user can:
• Boot a specific device, using the abbreviated path identifier, or the full mnemonic.
• Start a device search where the contents are searched for
IPL images (note the first search only
identified devices and did not check the contents).
• Enter the boot administration level.
• Exit the menu and return to autobooting
• Get help on choices
The search of potentially bootable devices can be aborted by pressing and holding the escape key. The
search for device contents can also be aborted by pressing and holding the escape key.
HP-UX 11i Version 2: August 2003 − 1 − Hewlett-Packard Company Section 1M−−605