Programming with Judy

About Judy
When To Use Judy
Chapter 112
Judy libraries The table below shows the location of the libraries that are provided with
the Judy technology on the HP-UX system:
NOTE The 32-bit HP-PA 1.1 shared library (/usr/lib/libJudy.sl) is provided for
compatibility only. For best performance on 32-bit machines, use the
HP-PA 2.0 shared library (/usr/lib/pa20_32/libJudy.sl).
Development
history
The Judy code has been tested and improved over several internally
available iterations at HP. The most recent version runs about twice as
fast as the previous version. This version of Judy was designed to
maintain very good memory allocation of not more than 12 bytes per
index for 32-bit machines and 24-bytes per index for 64-bit machines. In
fact, for large populations of clustered data, memory efficiency can be
less than 8 bytes per index on a 32-bit machine or 16 bytes per index on a
64-bit machine.
The Judy concept has been generating engineering interest at HP for
years with early research and prototyping dating back to 1981. The
current Judy technology has been under active engineering development
for four years. Judy has been proven in several internal HP tools and
products, including a performance profiling tool, a disk work-load
analyzer (WLA), and the OpenGL (Graphics Library). (See Appendix A,
“Where Did Judy Come From?,” on page 59.)
Judy is a technology with patents pending that was invented and
implemented by Hewlett-Packard.
Hardware
Architecture
Type Location on system (from root)
32-bit 64-bit
HP-PA 1.1
(32-bit only)
archive /usr/lib/libJudy.a N/A
shared /usr/lib/libJudy.sl N/A
HP-PA 2.0 archive none /usr/lib/pa20_64/ libJudy.a
shared /usr/lib/pa20_32/libJudy.sl /usr/lib/pa20_64/libJudy.sl