Reference: May 07, 1999
USGS Revision and Product Generation Software (RevPG)
The U.S. Geological Survey (UsGS) developed revision and product generation (RevPG) software for updating digital line graph (DLG) data and producing maps from such data.
Note the system requirements:
UNIX Operating Systems
28 Megabytes of RAM
21 Megabytes of Disk Space
100 Megabytes of Swap Space