One of the design goals of Firebird 1.5 is to prepare the way for multiple installs of the server. This will allow users to run different versions side by side. Firebird 1.5 does support this, although it is not well documented and very much requires intervention from a skilled user. Future versions of Firebird will make this process far less complicated. In the meantime Firebird 1.5 needs to prepare the ground. This forces us to confront the issue of library installation. At the same time, Microsoft have taken their own steps to manage installation of different library versions. Taken together these two separate issues mean a new approach to library installation for Firebird 1.5 and beyond. 1/ Installation of Microsoft system libraries. The problems associated with installing different versions of Microsoft system libraries are so notorious that it has acquired the name 'DLL Hell'. From the release of Windows 2000 onwards Microsoft have made it almost impossible to upgrade system dll's. To resolve this Microsoft now recommend that each application installs local copies of any system libraries that are required. Firebird 1.5 follows this practice for all Microsoft platforms from Windows 2000 onwards and places the required libraries in the \bin directory along with the server. When installed on older systems (Win 9x, NT) it follows the standard practice and attempts to upgrade older versions of the system libraries. 2/ Installation of fbclient.dll. Firebird 1.5 and beyond no longer use gds32.dll as the client library. It is now called fbclient.dll. Given the problems that Microsoft have had with DLL hell it wouldn't make much sense if we continued to store the Firebird client library in the directory. And as we want to allow installation of multiple engines simultaneously we would be creating our own DLL hell if we continued the practice of using the directory for the client library. So, from Firebird 1.5 on, the client library resides in the \bin directory along with all the other binaries. A new registry key has been added and all Firebird compliant applications should now use this to locate the correct version of Firebird that they wish to use. The new key is: HKEY_LOCAL_MACHINE\SOFTWARE\Firebird Project\Firebird Server\Instances Firebird will guarantee that one entry under this key always exists. It will be known as "DefaultInstance" and will store the path to the root directory of (yes, you've guessed it) the default installation. Those that don't care about particular installations can alway use the default instance to locate the fbclient.dll. Future versions of Firebird will see other entries under Instances. Applications will be able to enumerate the registry entries to determine which library instance the wish to load. 3/ Supporting legacy applications and drivers. Traditionally, applications that use InterBase or Firebird have expected to load the gds32.dll client library from the directory. Firebird 1.5 ships a tool named 'instclient.exe' that can install a clone of fbclient.dll to the Windows System directory. This clone gets patched on the fly so that its file version information starts in "6.3". This is done so because some old applications do extra checks on the GDS32.DLL file version. Based on a lot of experiments, it has been determined that 6.3 is a safe "compatible" version number to use, much better than "1.5". During the installation process the installer checks to see if an installation of InterBase or Firebird exists. If nothing is installed it will write a patched gds32.dll into the directory. If it detects that any possible version of Firebird or InterBase may already be installed it will not install the gds32.dll in the directory. However you can always do so later by using the new 'instclient.exe' tool. It is intended that future versions of Firebird will not attempt to install gds32.dll into the directory and ultimately it will be completely removed from the distribution. This 'instclient.exe' tool can also install the FBCLIENT.DLL itself in the Windows system directory. This can be preferred by some tools or applications and we don't want to miss any use case. instclient Usage: instclient i[nstall] [ -f[orce] ] library q[uery] library r[emove] library where library is: fbclient | gds32 This utility should be located and run from the 'bin' directory of your Firebird installation. '-z' can be used with any other option, prints version Purpose: This utility manages deployment of the Firebird client library into the Windows system directory. It caters for two installation scenarios: Deployment of the native fbclient.dll. Deployment of gds32.dll to support legacy applications. Version information and shared library counts are handled automatically. You may provide the -f[orce] option to override version checks. Please, note that if you -f[orce] the installation, you might have to reboot the machine in order to finalize the copy and you might break some other Firebird or InterBase(R) version on the system.