Impressario provides an open printing and scanning environment. Third party support for printers and scanners can be plugged into the Impressario environment by following the procedures described in this chapter.

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Note: As of this writing, Silicon Graphics is in the process of making its inst software packaging and installation technology available to its developers. The inst software packaging mechanism is far superior to the use of tar archives. When available, inst software packaging should be used instead of tar archives.

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The current method for creating an Impressario software distribution uses the tar(1) file archiving program. To create a software distribution use the following procedure.

To illustrate better the process of packaging Impressario printing support software, let us create a fictitious product. The product will provide Impressario support for the Blast family of printers. The Blast product line consists of the Blast 1, Blast 2CVX, and the Blast P+. Since each of the Blast printers is similar in functionality, support for all of them will be provided by a single model file.

Impressario printing support products typically are named with the printer family, the word Print and the lowest version number of Impressario that supports the product. In keeping with this convention, we will name our product "BlastPrint for Impressario 1.2".

A typical Impressario printer support product consists of the following files:

Model file		When the printer is registered with the spooling system, this file is copied and becomes the printer interface file. The spooling system executes this shell script for each print job.
Driver		This executable program performs the work of communication with the printer. The interface file invokes the driver to do the actual printing of a file. The driver sends data to the printer and updates the POD status file.
POD files		The POD consists of three files, all with the same basename as the model file but with the suffixes config, status, and log. These plain text files contain static and dynamic printer information.
Graphical options panel program		This GUI program provides users with graphical access to printer specific options. The program is given the same basename as the model file with the suffix gui.
Graphical options panel resource file		This is an X Window system resource file for the graphical options panel program. The file is named with the class name of the graphical options panel program. This name must also match the GUI_CLASS variable in the model file.
Manual page		A manual page should be created that describes the printing product. By convention, this manual page should be named with the product name. The manual page must be formatted using nroff(1) and must be compressed before installation. A product manual page template and a Makefile to perform the required formatting, compression, and installation is provided in the directory /usr/impressario/man. Note: In order to create a manual page you must have the Documenter's Workbench product installed on the development system.

The files listed in Table 11-1 comprise the BlastPrint product. The files are listed with their absolute pathnames, ownership, and permissions.

Before creating the actual software distribution, the above files must be copied to the directories indicated and given the specified ownership and permissions. Once this is done, the Impressario test program testiconfig(1) can be run to verify that the product conforms to Impressario product installation specifications.

To run the testiconfig program on the BlastPrint product, execute the following:

cd /usr/impressario/tests/print
./testiconfig blast_model

Once the product installation has been verified, a software distribution can be created. This is done using the tar(1) command. Assuming we are making a tape distribution, we would issue the following command (note the use of the line continuation character `\' to allow the command line to extend over multiple lines):

tar cvLf /dev/tape /var/spool/lp/model/blast_model \
                /usr/lib/print/blaster \
                /usr/lib/print/data/blast_model.config \
                /usr/lib/print/data/blast_model.status \
                /usr/lib/print/data/blast_model.log \
                /var/spool/lp/gui_model/ELF/blast_model.gui \
                /usr/lib/X11/app-defaults/Blast \
                /usr/share/catman/u_man/cat1/blastprint.z

The resulting tape archive represents the BlastPrint product.

It is recommended that the copying of the files to their installation directories, the assigning of ownership and permissions, and the archiving of the files all be automated in a shell script. This eliminates a large amount of typing and provides a reproducible distribution mechanism.

Once the distribution tape has been created, it should be taken to a new system (in other words, one that has never had BlastPrint installed) and installed. This is done using the following command as superuser:

tar xvf /dev/tape

Once BlastPrint has been installed, the testiconfig program should again be run to verify that the installation is complete and correct. A printer should then be connected to the system and registered with the spooling system using the Printer Manager (printers(1M)). The Impressario test program testipr(1) should be run on the newly installed printer to verify that it is able to print all supported Impressario file formats and options.

If the printer was installed with the name myblaster, it can be tested by executing the commands:

cd /usr/impressario/tests/print
./testipr myblaster

This completes the creation of an Impressario printer support product.

To illustrate the process of packaging Impressario scanning software, we will create a fictitious product to provide Impressario support for the LowTech 100 scanner.

Impressario scanning products are typically named with the scanner family, the word Scan, and the lowest version number of Impressario that supports this product. We will name our product "LowTechScan for Impressario 1.2".

A typical Impressario scanner support product consists of the following files:

Scanner driver		The executable program that gets the data from a scanner.
Graphical options program		Graphical scanner-specific options program launched from a scanning application. The graphical options program showcases a scanner's features. This program must have the same base name as the scanner driver in order to be recognized by scanners(1M), the scanner install tool.
Graphical options resource file		X Window System resource file for the graphical options program. This file is named with the class name of the graphical options program. This class name must be the same as the graphical options program name with the first letter capitalized. If the graphical options program resource file is not named using these conventions, the options program will not have access to its resources when invoked for a network scanner.
Manual page		A manual page should be created that describes the scanning product. By convention, this manual page should be named with the product name. The manual page must be formatted using nroff(1) and must be compressed before installation. A product manual page template and a Makefile to perform the required formatting, compression, and installation is provided in the directory /usr/impressario/man. Note: In order to create a manual page you must have the Documenter's Workbench product installed on the development system.

The files listed in Table 11-2 comprise the LowTechScan product. The files are listed with their absolute pathnames, ownership, and permissions

Before creating the actual software distribution, the above files must be copied to the directories indicated and given the specified ownership and permissions. Then the scanners(1M) tool should be run to verify that the correct string for the LowTech 100 scanner appears in the "Install New Scanner" dialog. The scanners tool should be used to install a LowTech 100 scanner, and gscan(1) should be able to run the graphical options program from the "Scanner Specific Options" command on the "Parameters" menu.

Once the product installation has been verified, a software distribution can be created. This is done using the tar(1) command. Assuming we are making a tape distribution, we would issue the following command (note the use of the line continuation character `\' to allow the command line to extend over multiple lines):

tar cvLf /dev/tape /usr/lib/scan/drv/lowtech \
         /usr/lib/scan/opt/lowtech \
         /usr/lib/X11/app-defaults/Lowtech \
         /usr/share/catman/u_man/cat1/lowtech.z

The resulting tape archive represents the LowTechScan product.

It is recommended that the copying of the files to their installation directories, the assigning of ownership and permissions, and the archiving of the files all be automated in a shell script. This will eliminate a large amount of typing and provides a reproducible distribution mechanism.

Once the distribution tape has been created, it should be taken to a new system (in other words, one that has never had LowTechScan installed) and installed. This is done using the following command as superuser:

tar xvf /dev/tape

Once LowTechScan has been installed, the scanners and gscan programs should again be run to verify that the installation is complete and correct.

This completes the creation of an Impressario scanner support product.