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The 1998 ACM Computing Classification System

The ACM Computing Classification System [1998 Version]

The full classification scheme involves three concepts (described more fully in the Introduction): the four-level tree (containing three coded levels and a fourth uncoded level), General Terms, and implicit subject descriptors. (See also the Report of the CCS Update Committee (pdf)). For information on how to classify works using the CCS, see How to Classify Works Using ACM's Computing Classification System.

The full CCS classification tree is available as a single HTML document; as an ascii file; or as an xml file.

Nodes in parentheses indicate a cross-reference to related material.

General Terms

These apply to any elements of the tree that are relevant.

  • Algorithms
  • Design
  • Documentation
  • Economics
  • Experimentation
  • Human Factors
  • Languages
  • Legal Aspects
  • Management
  • Measurement
  • Performance
  • Reliability
  • Security
  • Standardization
  • Theory
  • Verification

Implicit Subject Descriptors

Uncoded items are Implicit Subject Descriptors.

Implicit Subject Descriptors (also called "Proper Noun Subject Descriptors") are proprietary names of products, systems, languages, and prominent people in the computing field, along with the category code under which they are classified. For example, "C++" is under "D.3.2 Language Classifications". Listing is alphabetical by name. Sort of people's names is by first name, not surname.

Implicit Subject Descriptors do not appear as part of the formal scheme because they are too numerous to include without making the scheme too cumbersome. Please note that this list is dynamic and sees frequent updates as new names are introduced. Please send suggestions for names you do not see on the list, along with a brief explanation of the name's significance and (if possible) the CCS category under which the name should be classified, to

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