pdc - processor-dependent code (firmware)
is the firmware that implements all processor-dependent functionality, including initialization and self-test of the processor. Upon com-
pletion, it loads and transfers control to the initial system loader (isl(1M)). Firmware behavior varies somewhat, depending on the hard-
ware as described below.
To load from an external medium, must know the particular device on which resides. Typically the device is identified by the Primary Boot
Path that is maintained by 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, reads the Console Path from Stable Storage, and attempts to ini-
tialize the console device. If the initialization fails, attempts to find and initialize a console device. Algorithms used to find a con-
sole device are model-dependent. then announces the Primary Boot, Alternate Boot, and Console Paths.
If (see isl(1M)) is enabled, provides a 10-second delay, during which time the operator can override the sequence by typing any character
on the console. If the operator does not interrupt this process, initializes and reads from the Primary Boot Path. On models that support
autosearch, if this path is not valid and (see isl(1M)) is enabled, then searches to find a bootable medium.
If allowed to complete, a list of potentially bootable devices is displayed, labeled with abbreviated path identifiers (P0, P1, etc). A
simple menu is then displayed where the user can:
o Boot a specific device, using the abbreviated path identifier, or the full mnemonic.
o 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).
o Enter the boot administration level.
o Exit the menu and return to autobooting
o Get help on choices
If the sequence is unsuccessful, overridden by the operator, or not enabled in the first place, 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 and enable can be modified via
PA-RISC Systems Only pdc(1M)