1.8. GPHIGS ARCHITECTURE
The following diagram shows the GPHIGS architecture:
Figure 1.8.a
GPHIGS has at its core a kernel which manages both the Centralized
Structure Store (CSS) and archive files. Below the kernel level is a metadriver
whose call level is completely based on the PEX protocol. Below this level are
the drivers, in particular the X-Window driver. The diagram also shows the
separation between output and input since input is, in fact, managed by an
independent process, called the PHIGS Input Manager (PIM), activated when the
workstation is opened. The PIM handles communication with the output processor
via the PHIGS Input Interface (PII). The PIM manages inputs for all types of
X-based workstations: X11, GDI, Xgl, GL, OpenGL, PEXlib. In this case, GPHIGS
creates an X window, initializes the PIM and then initializes the 3D graphic
library.