17.9 The Imprints Toolset

The Imprints tool set provides a UNIX equivalent of the Windows NT Add Printer Wizard. For complete information, please refer to the Imprints Web site at http://imprints. sourceforge .net/ as well as the documentation included with the imprints source distribution. This section only provides a brief introduction to the features of Imprints.

Unfortunately, the Imprints toolset is no longer maintained . As of December 2000, the project is in need of a new maintainer. The most important skill to have is Perl coding and an interest in MS-RPC-based printing used in Samba. If you wish to volunteer, please coordinate your efforts on the Samba technical mailing list. The toolset is still in usable form, but only for a series of older printer models where there are prepared packages to use. Packages for more up-to-date print devices are needed if Imprints should have a future.

17.9.1 What is Imprints?

Imprints is a collection of tools for supporting these goals:

Providing a central repository of information regarding Windows NT and 95/98 printer driver packages.
Providing the tools necessary for creating the Imprints printer driver packages.
Providing an installation client that will obtain printer drivers from a central Internet (or intranet) Imprints Server repository and install them on remote Samba and Windows NT4 print servers.

17.9.2 Creating Printer Driver Packages

The process of creating printer driver packages is beyond the scope of this document (refer to Imprints.txt also included with the Samba distribution for more information). In short, an Imprints driver package is a gzipped tarball containing the driver files, related INF files, and a control file needed by the installation client.

17.9.3 The Imprints Server

The Imprints server is really a database server that may be queried via standard HTTP mechanisms. Each printer entry in the database has an associated URL for the actual downloading of the package. Each package is digitally signed via GnuPG which can be used to verify that the package downloaded is actually the one referred in the Imprints database. It is strongly recommended that this security check not be disabled.

17.9.4 The Installation Client

More information regarding the Imprints installation client is available from the the documentation file Imprints-Client-HOWTO.ps that is included with the Imprints source package. The Imprints installation client comes in two forms:

A set of command line Perl scripts.
A GTK+ based graphical interface to the command line Perl scripts.

The installation client (in both forms) provides a means of querying the Imprints database server for a matching list of known printer model names as well as a means to download and install the drivers on remote Samba and Windows NT print servers.

The basic installation process is in four steps and Perl code is wrapped around smbclient and rpcclient.

For each supported architecture for a given driver:
1. rpcclient: Get the appropriate upload directory on the remote server.
2. smbclient: Upload the driver files.
3. rpcclient: Issues an AddPrinterDriver() MS-RPC.
rpcclient: Issue an AddPrinterEx() MS-RPC to actually create the printer.

One of the problems encountered when implementing the Imprints tool set was the name space issues between various supported client architectures. For example, Windows NT includes a driver named " Apple LaserWriter II NTX v51.8 " and Windows 95 calls its version of this driver " Apple LaserWriter II NTX ".

The problem is how to know what client drivers have been uploaded for a printer. An astute reader will remember that the Windows NT Printer Properties dialog only includes space for one printer driver name. A quick look in the Windows NT 4.0 system registry at:

 HKLM\System\CurrentControlSet\Control\Print\Environment

will reveal that Windows NT always uses the NT driver name. This is okay as Windows NT always requires that at least the Windows NT version of the printer driver is present. Samba does not have the requirement internally, therefore, " How can you use the NT driver name if it has not already been installed? "

The way of sidestepping this limitation is to require that all Imprints printer driver packages include both the Intel Windows NT and 95/98 printer drivers and that the NT driver is installed first.