Prerequisite Software

by Joel Aufrecht

OpenACS docs are written by the named authors, and may be edited by OpenACS documentation staff.

OpenACS requires, at a minimum, an operating system, database, and webserver to work. Many additional programs, such as a build environment, Mail Transport Agent, and source control system, are also needed for a fully effective installation.

Table 2.2. Version Compatibility Matrix

OpenACS Version3.
8.5.4 -Maybe
7.3.2 - 7.3.xNoYesNo
8.2NoCVS version onlyYes

The OpenACS installation instructions assume the operating system and build environment are installed. The instructions explain installation of Tcl, Tcllib, tDOM, tclwebtest, a Web Server, a Database, a Process Controller, and Source Control software. The following external links are for reference only.

  • OpenACS 5.9.0The OpenACS tarball comprises the core packages and many useful additional packages. This includes a full set of documentation. The tarball works with both PostgreSQL and Oracle. Some scripts require bash shell.

  • Operating System. OpenACS is designed for a Unix-like system. It is developed primarily in Linux. It can be run on macOS, and in Windows within VMWare.

    • GNU/Linux. The installation assumes a linux kernel of 2.2.22 or newer, or 2.4.14 or newer.

    • FreeBSD. FreeBSD guide. The OpenACS Reference Platform uses shell scripts written for bash, which is the standard Linux shell. If you are using a different shell, you will need to substitute your shell's conventions for setting environment variables when appropriate, and install bash to work with the scripts. Substitute fetch when the instructions suggest you use wget to download software.

    • macOS. the section called “OpenACS Installation Guide for macOS”

    • Windows/VMWare. the section called “OpenACS Installation Guide for Windows” The only way to run OpenACS on Windows is through the VMWare emulator. (Please let me know if you have OpenACS running directly in Windows.)

  • Build Environment. The Reference Platform installation compiles most programs from source code.

    • glibc 2.2 or newer, REQUIRED. You need recent versions of these libraries for Oracle to work properly. For Unicode support, you need glibc 2.2 or newer. This should be included in your operating system distribution.

    • GNU Make 3.76.1 or newer, REQUIRED. PostgreSQL and AOLserver require gmake to compile. Note that on most linux distributions, GNU Make is simply named make and there is no gmake, whereas on BSD distributions, make and gmake are different --use gmake.

  • Tcl 8.5.x. 

    • Tcl 8.5.x, REQUIRED. OpenACS is written in Tcl, an interpreted language. A threaded version of the Tcl interpreter must be installed for OpenACS to work. The Tcl interpreter that is included in most standard distributions may not be thread safe.

    • Tcl 8.5.x development headers and libraries, OPTIONAL.  The site-wide-search service, OpenFTS, requires these to compile. (Debian users: apt-get install tcl8.5-dev). You need this to install OpenFTS.

  • Tcllib, REQUIRED.  OpenACS 5.9.0 uses those Tcl extensions to send e-mail out, among others.

  • tDOM, REQUIRED. OpenACS 5.9.0 stores queries in XML files, so we use an AOLserver module called tDOM to parse these files. (This replaces libxml2, which was used prior to 4.6.4.)

  • tclwebtest, OPTIONAL. tclwebtest is a tool for testing web interfaces via Tcl scripts.

  • Web Server. The web server handles incoming HTTP requests, provides a run time environment for OpenACS's Tcl code, connects to the database, sends out HTTP responses, and logs requests and errors. OpenACS uses AOLserver; some people have had success running Apache with mod_nsd.

    • AOLserver 4.x, REQUIRED. Provides the base HTTP server

    Mat Kovach is graciously maintaining an AOLserver distribution that includes all the patches and modules needed to run OpenACS 5.9.0. These instructions will describe how to install using his source distribution. He also has binaries for SuSE 7.3 and OpenBSD 2.8 (and perhaps more to come), currently located at

    It's also possible to download all the pieces and patches yourself:

    • AOLserver is available at

    • The OpenACS PostgreSQL driver ( is available from SourceForge. If you do decide to use, you have to remember to change the AOLserver config file to point to instead of This guide uses Mat Kovach's distro (i.e.

    • The patch that makes exec work on BSD is available at

    • The patch for AOLserver 3.x that makes ns_uuencode work for binary files is available at

    • The patch that makes AOLserver 3.x respect the -g flag is available at

  • nsopenssl, OPTIONAL. Provides SSL capabilities for AOLserver. It requires OpenSSL. You need this if you want users to make secure (https) connections to your webserver. aolserver3.x requires nsopenssl 2.1a. aolserver4.x requires nsopenssl3; see for latest release. (home page)

  • ns_pam 0.1 or newer, OPTIONAL. Provides PAM capabilities for AOLserver. You need this if you want OpenACS users to authenticate through a PAM module (such as RADIUS).

  • pam_radius 1.3.16, OPTIONAL. Provides RADIUS capabilities for PAM. You need this if you want to use RADIUS authentication via PAM in OpenACS.

  • ns_ldap 0.r8, OPTIONAL. Provides LDAP capabilities for AOLserver. You need this if you want to use LDAP authentication in OpenACS.

  • OpenFTS Tcl 0.3.2, OPTIONAL. Adds full-text-search to PostgreSQL and includes a driver for AOLserver. You need this if you want users to be able to search for any text on your site. For postgres 7.4.x and higher, full text search is also available via tsearch2.

  • Analog 5.32 or newer, OPTIONAL. This program examines web server request logs, looks up DNS values, and produces a report. You need this if you want to see how much traffic your site is getting.

  • Balance 3.11 or newer, OPTIONAL. "Balance is a simple but powerful generic tcp proxy with round robin load balancing and failover mechanisms." You need this or something equivalent if you are running a high-availability production site and do not have an external load balancing system.

  • Database. The data on your site (for example, usernames and passwords, calendar entries, and notes) is stored in the database. OpenACS separates the database with an abstraction layer, which means that several different databases all function identically. While you can run the core OpenACS on any supported database, not all contributed packages support all databases.

    • Oracle 8.1.7 (Either this or PostgreSQL is REQUIRED). You can register and download Oracle from Oracle TechNet. You need this if you want to use an Oracle database.

    • PostgreSQL 7.4.x (Either this or Oracle is REQUIRED). You need this if you want to use a PostgreSQL database.

  • Process Controller. This is software that initiates other software, and restarts that software if it fails. On Linux, we recommend using Daemontools to control AOLserver and qmail.

    • Daemontools 0.76, OPTIONAL. You need this if you want AOLserver and qmail to run "supervised," meaning that they are monitored and automatically restarted if they fail. An alternative would be to run the services from inittab.

  • Mail Transport Agent. A Mail Transport Agent is a program that handles all incoming and outgoing mail. The Reference Platform uses Qmail; any MTA that provides a sendmail wrapper (that is, that can be invoked by calling the sendmail program with the same variables that sendmail expects) can be used.

    • Netqmail 1.04, OPTIONAL. You need this (or a different Mail Transport Agent) if you want your webserver to send and receive email.

    • ucspi-tcp 0.88, OPTIONAL. This program listens for incoming TCP connections and hands them to a program. We use it instead of inetd, which is insecure. You need this if you are running qmail.

  • DocBook, OPTIONAL. (docbook-xml v4.4, docbook-xsl v1.56, libxslt 1.0.21, xsltproc 1.0.21). You need this to write or edit documentation.

  • Source Control. A Source Control system keeps track of all of the old versions of your files. It lets you recover old files, compare versions of file, and identify specific versions of files. You can use any source control system; the Reference Platform and the repository (where you can get patched and development code in between releases) use cvs.

    • cvs 1.11.18, OPTIONAL. cvs is included in most unix distributions. You need this if you want to track old versions of your files, do controlled deployment of code from development to production, or get or contribute development code from

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