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)).

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 an HP-IB card, the next number is the HP-IB address, followed by the unit number of the device if the device supports units.  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 then provides a 10-second delay, during which time the operator can override the autoboot sequence by entering 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 implemented 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 and autoboot and autosearch enable may be modified via isl. 

SEE ALSO

boot(1M), hpuxboot(1M), isl(1M). 

Hewlett-Packard Company  —  HP-UX Release 7.0: Sept 1989