Using EXTRACT with Data on DVD-ROM

Foreign Trade--Imports and Exports

EXTRACT works with data sets on CD-ROM, but not on DVD-ROM, due to a difference in the way Windows operating systems deal with the two types of media. To continue using EXTRACT with these data, copy all or most of the files on the DVD-ROM to your hard disc or to a network drive, redefine the location to which you copied the files as a "virtual CD", and finally unprotect all of the files copied.

  1. Find a location on your hard disc or network drive that can accommodate the data. (The December 2002 Imports of Merchandise disc requires 700 mb of space).

  2. Copy all of the contents of the root directory and the AUXIL directory to new location.

  3. Redefine the location to which you copied the files as a separate drive. EXTRACT expects imports and exports data files to be in the root directory of a drive, so you must map a network drive or local drive to accommodate it.

  4. Unprotect the files in the root directory and AUXIL subdirectory of your virtual CD.

  5. Execute EXTRACT, but now directing the software using the drive letter selected in step 3 above.

Each time you get a new DVD for a different data month or year, you will need to go through these same steps, except that you may reuse the same virtual drive each time.

If you use both imports and exports discs or both monthly and historical (5-year) discs, create a different virtual drive for each type of disc. The master.ctg file differs for each type of disc.

Source: U.S. Census Bureau, Economic Planning and Coordination Division
Last revised: July 13 2011