How do I install multiple versions, minor versions and patches of ACS on the same machine at the same time? How do I switch between different versions of ACS?

Problem

Solution

Standard installation

A standard ACS installation directory has the name defined by the major and minor version numbers:

/alma/ACS-X.Y
where X and Y are respectively the major and minor version numbers

A non-standard installation can be done in arbitrary directories, but for absolute path problems with the GNU gcc compiler and tcl/tk.

This convention is based on the rule that the tools distributed with ACS shall not change for a patch release (third version number) and patch releases have to be 100% backward compatible.

Patch releases

A patch release is installed by replacing the directories:

/alma/ACS-X.Y/acsdata
/alma/ACS-X.Y/ACSSW

with a new version.

The location of these two directories is controlled by the environment variables $ACSDATA and $ACSROOT and it is therefore possible to point to different patch versions simply by changing these two variables.

It is always possible to know what version/patch of ACS is installed in a certain directory tree by looking at the files:

/alma/ACS-Y.Y1/ACSSW/ACS_VERSION
/alma/ACS-Y.Y1/ACSSW/ACS_PATCH_LEVEL
/alma/ACS-Y.Y1/ACSSW/ACS_TAG

where the actual name of ACSSW might depend on your installation.

Note: Notice that this cannot take into account patching done by hand.

New ACS build

A new build of ACS always creates a clean ACSROOT and ACSDATA directories, but also keeps a backup of the previously installed one.

In this way the new build replaces transparently the old one.

Starting with ACS 4.1, the ACS build procedure assigns if possible to these directories a name which is postfixed with the ACS version and patch level or, if pre-existing, the CVS tag. If a tag does not exist or the directories with that name already exist, it will generate a unique postfix (this was the only action before ACS 4.1)

The backup copy can be later removed or kept in parallel to the new one.

ACS update

Starting with ACS 4.1 the script acsUpdate is available to install a new ACS patch on top of a pre-existing installation of the same ACS major&minor version from a binary distribution tar file.

The ACSROOT and ACSDATA directories from the tar file replace the existing ones, but a backup copy of the previously installed ones is kept according to the same rules described above.