| User interface basics / Connecting to a GUI front-end | |
GUI protocol compression might be used in the GUI protocol to reduce the amount of data exchanged between the front-end and the application server. Compression is typically useful on slow networks. The compression algorithm is provided by the standard ZLIB library of the system.
When using the Genero Web Client (GWC/GAS), compression is not useful and is automatically disabled.
Compression makes sense on slow networks (for example, with a phone-line dialup modem, or broadband modem based networks); On fast networks (like 100 Mbps Ethernet based networks), compression uses unnecessary processor time.
Compression is disabled by default, and can be enabled with this FGLPROFILE entry:
gui.protocol.format = "zlib"
If this parameter is defined, but the ZLIB library is not installed on your system or if the ZLIB version is not compatible with the version needed by the runtime system, compression cannot be supported, and the program will stop with error -6317. The ZLIB version must be 1.2.5 (or compatible with version 1.2.5). On Microsoft™ Windows™ platforms, the name of the library must be ZLIB1.DLL; Precompiled binary packages can easily be found on the internet. On UNIX™ platforms, the name of the shared library must be libz.so (normally located in /usr/lib). Note that on Linux™ distributions, you typically have to install the zlib (or zlib1g) package and create a symbolic link for libz.so. The libz.so file is part of zlib-devel package, though.