HP-UX 11i September 2002 Release Notes

Internet and Networking Services
Low Bandwidth X Extension (LBX)
Chapter 12
234
graphics displays can be achieved than otherwise would be possible with a single system
with multiple graphics cards. SLS/d provides the X Window system support for part of
the 3-D Visualize Center products.
SLS/d involves a low-level change in the X server that unites several distributed
graphics displays into a logical X Window system. The only user-visible changes are
related to system configuration. The X Window system API remains unchanged in the
SLS/d system, and thus is completely transparent to 2-D X window applications. The
motivation behind this new functionality is to increase the size of the logical screen
beyond what is possible using a single system with multiple graphics cards.
A new driver and a new X server extension have been added to the X server in order to
implement this change. The functionality is enabled by modifying the server's X* screens
file. The full documentation for the SLS/d functionality can be found in the X server
information file, /usr/lib/X11/Xserver/info/screens/hp, and in the Graphics
Administration Guide.
An SLS daemon and a configuration tool are delivered to aid system configuration. The
daemon is controlled via start and stop scripts that reside in the /sbin/init.d,
/sbin/rc1.d, and /sbin/rc2.d directories. The SLS daemon is started when the
system enters run-level 2 or greater, and stopped when the system enters run-level 1.
See the X server documentation for more details.
The performance of SLS/d depends on the performance of the underlying network to
which the SPUs in the system are connected. On a dedicated network with a 100 Base-T
backbone, the 2-D X Windows performance approaches that of a single SPU SLS system.
SLS/d is transparent to applications in the same manner as SLS. Once the system has
been configured, it behaves identically to a single screen X Window system, albeit with a
much larger screen size. One requirement is that the underlying graphics cards in the
system be homogeneous. Although not a strict requirement, it is also desirable that the
systems participating in the SLS/d system be homogeneous as well.