As of May 21, 2004, the National Library of Canada (NLC) and the National Archives of Canada (NAC) became Library and Archives Canada (LAC). The National Library of Canada (NLC) Control Number was renamed to Library and Archives Canada (LAC) Control Number in Update no. 5 of the MARC 21 format for Bibliographic data.

In order to accommodate the century change, the National Library of Canada is planning to change the structure of its control number (present in fields 001 and 016 in records distributed by the Library through its MARC Records Distribution Service).

The current structure of the number is:

Positions Element
0  Blank
1-2  Year
3-8  Number
9  Check digit
10  Language code
11  Blank
12-n  Revision indicator

In order to avoid ambiguity in records distributed in the year 2001 and beyond, the Library has decided to expand the year element from two digits to four digits. The proposed new structure is:

0-3  Year
4-9  Number
10  Check digit
11  Language code
12-n  Revision indicator

Implementation:

NLC control numbers assigned prior to implementation will not be changed.

The new structure was be implemented in January 2001.

Open Data, Content Management Division
Library and Archives Canada
Ottawa, ON   K1A 0N4
CANADA
Telephone: 819-994-6936
Fax: 819-934-4388
Email: marc21@bac-lac.gc.ca