From V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016) :
PHB
PCI Host Bridge (Power4, IBM)
From The Jargon File (version 4.4.7, 29 Dec 2003) :
PHB
/P?H?B/
[Usenet; common; rarely spoken] Abbreviation, ?Pointy-Haired Boss?. From
Dilbert+character,+the+archetypal+halfwitted+middle-{management">the Dilbert character, the archetypal halfwitted middle-{management
type. See also pointy-haired.