Packaging of Software Products

AIX Version 4.3 Installation Guide

Packaging of Software Products

Note: Application developers who want to develop software packages to be installed using the installp command should refer to "Packaging Software for Installation" in AIX Version 4.3 General Programming Concepts: Writing and Debugging Programs.

The "packaging" of software products is divided into three categories: products, packages, and filesets. A product may be composed of several packages, which in turn are composed of different filesets. A product may be installed in its entirety, or only certain packages or filesets for the product may be installed. The installation packaging of a software product is divided in this way because many software products are large and have many pieces that can be used independently of each other. Dividing a product into separately installable filesets allows you to install only those filesets you need. You may prefer to install all the filesets included in a package or the entire product, or you may want to install only selected filesets, especially if you have limited hard disk space on your system.

The installation packaging of each fileset in a product may have been divided into three parts: the usr, root, and share parts. Although this can add further complexity to the understanding of the packaging, this parceling of a software product is necessary for the product to be used by diskless and dataless clients in AIX Version 4.3. These functions allow a product to be installed on one machine (called the server) and then be used remotely by other machines on a network (called the clients).

usr part	The usr part of a software product contains the part of the product that can be shared by machines that have the same hardware architecture. Most of the software that is part of a product usually falls into this category. In a standard system, the usr parts of products are stored in the /usr file tree. For example, the ls command would be in the /usr/bin/ls file.
root part	The root part of a software product contains the part of the product that cannot be shared. In a client/server environment, these are the files for which there must be a unique copy for each client of a server. Most of the root software is associated with the configuration of the machine or product. In a standard system, the root parts of a product are stored in the root (/) file tree. The /etc/objrepos directory contains the root part of an installable software product.
share part	The share part of a software product contains the part of the product that can be shared among machines, even if they have different hardware architectures. This would include nonexecutable text or data files. For example, the share part of a product might contain documentation written in ASCII text or data files containing special fonts. In a standard system, the share parts of products are usually stored in the /usr/share file tree. For example, a dictionary database might be stored in the /usr/share/dict/words file.

The share part of a product is optional because many products may not have any files that can be shared among different hardware platforms. The share part of a product is always packaged in a separately installable package. Every product has a usr part. The root part of a product is optional because many products may not have any files that need to be specific to each individual machine. The usr and root parts of a product are packaged together in the same installable package.