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Appendix B. UNIX Product Support (UPS) Overview
We mentioned earlier that UPS supports multiple versions of software products on a machine. End users do not find it convenient to specify product version numbers each time they setup a product. This is especially true if product setups are needed at login. Most users want to run the latest, tested, approved version of products without having to keep track of the version numbers.
To allow users to specify the version of a product according to its status rather than by its version number, UPS supports chains to product versions. A chain is a UPS database entry (i.e. a clause in a product file) that points to a particular instance declaration in the database (an instance clause in the same product file). It must match the (extended) flavor and version of the instance declaration exactly. It "attaches" a chain name to a product instance, thereby tagging the product instance according to its status.
Five statuses, or chains, have been defined for use: current, new, test, old, and development.
Chain | Option | Usage |
|---|---|---|
current | | default instance recommended for general use |
new | | tested instance that is not yet current |
test | | instance installed for testing |
development | | instance under development |
old | | older instance that was previously current |
In UPS commands, the command line option associated with the desired chain (status) is used to specify the product instance to retrieve. Using chains is optional, but recommended. Both chained and unchained instances of a product may be declared to UPS; the user can still retrieve any instance, chained or not, by using its product version number.