Obtaining a License Key


Running any version of Cyc other than OpenCyc requires a valid license key. Your institution should have received a valid license key at the time of acquiring your license. A license key consists of five groups of four hexadecimal digits (0-9, a-f) separated by the minus sign (ASCII code 45 in decimal, or 2D in hexadecimal). License keys are valid for a specific time period only; the exact duration is dependent on your license contract. An example (expired) license key is: d928-2826-1787-5fe9-6d31

A ResearchCyc license application is available here. If you need additional license keys, or your license key has expired, please contact us at license [at] cyc [dot] com.

Selecting an Appropriate Machine

System Requirements:


  • 64-bit OS
  • Java 1.6 or greater (64-bit)
  • 8 GB main memory (6GB Java VM)
  • 4 GB of available disk space
  • One dual-core CPU is fine, the faster the better


  • 64-bit Linux OS
  • Latest release version of Java 1.7 (64-bit)
  • 16 GB (or more) main memory (12GB Java VM)
  • 10 GB of available solid state disk (SSD) space
  • Fastest CPU (always prefer speed over number of cores)


Downloading Cyc

Along with your license key, you will be provided with a URL and a password with which you can download a Cyc installation bundle. Cyc installation bundles are either ZIP files or gzipped TAR files. Cycorp provides secure hash sums, typically SHA1 for Cyc installation bundles. Administrators can verify the correctness of a download using these hash sums and programs such as sha1sum or WinSHA1Sum.


Unpacking a Cyc Installation Bundle

Unpacking a Cyc installation bundle requires an archive program that can deal with the ZIP or gzipped TAR file format. On UN*X systems, command line tools such as unzip, gunzip and tar are available. On Windows systems, programs such as Winzip, 7-zip, and Cygwin ports of the UN*X command line tools are available.
Once an appropriate archive program is available, simply unpack the Cyc installation bundle to a local disk with sufficient space; use the archive program to determine how much room the installation requires.
A Cyc installation unpacks into one directory tree. The top level directory has a name of the form cyc-sys10.XXXXXX-kbYYYY, where XXXXX stands for the system version number and YYYY represents the number of the KB that is included with the Cyc installation.
For example, the top level directory cyc-sys10.134209-kb2100. indicates that this release has system version number 134209 and comes with KB number 2100.
The fully qualified path to the top-level directory is referred to as CYC_BASE_DIR in the remainder of this document.