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
- 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
- Copy all of the contents of the root directory and the AUXIL directory to
- In Windows Explorer-tm, click on the first file in the root directory,
shift-click on the last file, and control-click on the AUXIL directory,
and drag the marked files to your new location.
- 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
Unprotect the files in the root directory and AUXIL subdirectory of your
- If you copied the files to a network, in Windows Explorer, click on Tools
| Map Network Drive... and complete the dialogue. Click the checkbox
next to "Reconnect at logon" unless this is only a one-time use..
- If you copied the files to a local hard disc, open a MS-DOS window and
SUBST X: C:\directory
where X: is whatever unused drive letter you want to assign to the virtual
CD, and C:\directory is whatever location you copied the data files to.
You will need to repeat this step every time you run EXTRACT after rebooting.
Execute EXTRACT, but now directing the software using the drive letter selected in
step 3 above.
- In Windows Explorer, navigate to your virtual drive (e.g., X:), paint
all of the files in the root directory, right click and select
Properties, then click on the checkbox next to "Read-only" so
that it becomes blank. Click Apply and then OK.
- Repeat the process in the AUXIL subdirectory.
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
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