Package instances

Variations of a software package might reside on your system simultaneously. Each variation of a package is known as an ``instance'' and is treated as a separate entity. Three parameters, defined by the package developer, combine to uniquely identify each entity.

These parameters are:

PKG

the package abbreviation (which remains constant for every instance of a package)

VERSION

the software package version

ARCH

the software package architecture

For example, two versions of a package that run on the same system might be identified as:

   PKG="abbr"		PKG="abbr.1"
   VERSION="4.2 v1"	VERSION="4.2 v1.1"
   ARCH="(386)"		ARCH="(386)"

You cannot install on the same system two instances of a package that have the same package abbreviation (PKG).

Each package instance has a ``package identifier''. This ID maps the three identifying parameters to one name, the name of this package instance on your system.