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UMLS® Reference Manual [Internet]. Bethesda (MD): National Library of Medicine (US); 2009 Sep-.

Cover of UMLS® Reference Manual

UMLS® Reference Manual [Internet].

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Prior to the 2013AA release, the UMLS was available on a single disk DVD which contained the three UMLS Knowledge Sources in three compressed format files (.nlm data format) and the MetamorphoSys file. (File names for the 2009AA release are shown.)

  • 2009aa-1-meta.nlm
  • 2009aa-2-meta.nlm (Metathesaurus = 2 files)
  • 2009aa-otherks.nlm (Semantic Network and SPECIALIST Lexicon)
  •, MetamorphoSys - the UMLS installation and Metathesaurus subsetting program for PC and UNIX machines (cross-platform Java executable with JRE for each supported platform)

The DVD was discontinued as of the 2012AB UMLS release.

9.1 Hardware and Software Requirements

9.1.1 Supported Operating Systems

  • Windows Vista, XP, 2000, NT
  • Linux*
  • Solaris 9
  • Macintosh OS X (Leopard, Snow Leopard)**

*Linux note: The specific version fully validated is Red Hat Enterprise Linux WS, Version 5. Other versions should also work.

**Macintosh note: MetamorphoSys requires Java 1.6.

9.1.2 Hardware Requirements

  • A MINIMUM of 30 GB of free hard disk space
  • A MINIMUM of 2 GB of RAM, preferably more. Smaller memory size will cause virtual memory paging with exponentially increased processing time.
  • A CPU speed of at least 2 GHz
  • DVD drive

9.2 Installing from the DVD

Insert the DVD into a DVD drive. DVD drives must be mounted as UDF, the standard file system type for all DVDs. File length validation errors and other errors will result if a non-UDF drive is used. For best results the drive should be 6X or faster.

Start the MetamorphoSys install program:


  • The DVD should autorun.
  • If it does not (or if you are installing from the hard disk), go to the DVD root directory and click on "run.bat."

Linux, Solaris, and Macintosh

  • Open a terminal window and change to the root directory of the DVD, then type the appropriate command for your platform:




  • Hit the return key
  • Select "Install UMLS" on the Welcome to MetamorphoSys screen
  • Select destination (local) directory for files on the Install UMLS screen

The Install UMLS Metathesaurus progress monitor charts the process through:

  • Initializing the CUI list
  • Subsetting Content
  • Subsetting Indexes
  • Final Processes

If selected, Semantic Network and SPECIALIST Lexicon files are copied first. Accept the License Agreement notice to proceed with customizing the Metathesaurus.

Select "Cancel" to exit MetamorphoSys at any time. The interrupted process cannot be resumed. The configuration must be recalled (if saved), or recreated (if not saved), and subsetting must be started again.

MetamorphoSys produces an initial install.log file of the installation up to the start of Metathesaurus subsetting. If files pass validation, processing continues and subsetting begins. If validation fails, a warning is displayed and recorded in install.log.

When subsetting is complete, configuration settings are displayed on the screen and also written to "mmsys.log" in the directory containing the subsetted files. Your customized Metathesaurus files are located in the destination directory.

For more information on running MetamorphoSys see Chapter 8 of this documentation.

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