Archive Combat Air Activities File (CACTA)
Purpose Database about combat air missions in Vietnam
Institution in charge National Archives and Records Administration
Contents The Combat Air Activities File (CACTA) contains data from combat air missions in Southeast Asia, involving all the U.S. military services and the air force of South Vietnam. The “file” consists of 32 data files, each of which records information on the missions in a two-month period. The records describe air missions that flew between October 1965 and December 1970. No known data exists for November 1967. In 1971, the CACTA file was superseded by the Southeast Asia Data Base (SEADAB). Each CACTA record includes mission name and date; function and location of the mission; type, number, and identification of aircraft; results of the mission, including loss and
damage data about aircraft and crew; and free-text comments. Records also contain data about bombing runs in Vietnam, including the ordnance used and the geographic coordinates where the ordnance was dropped.
Technologies used
The Combat Air Activities File (CACTA), as several of the Vietnam-era data files held in the
Center for Electronic Records of the National Archives, were created by the Department of Defense using an early data base management system called the National Military Command System Information Processing System 360 Formatted File System, commonly known as NIPS. The data structure of NIPS files is hierarchical in that each data record is composed of fixed, non-repeating data with one level of subordinating data. Each record is of varying length and is usually organized into the following sets of data elements: a Control Set, in which a unique record identifier is found, such as operations report number; a Fixed Set, containing non-repetitive data; and one or more types of Periodic Sets. Each type of Periodic Set may occur one or more times. In addition, NIPS
files can include Variable Sets that appear only whe n data is present.
Relevance of the archive
During the War in Vietnam, the US heavily bombed portions of the Ho Chi Min Trail in eastern Laos – over 2 million tons of bombs. As much as 30 % of the ordnance dropped did not explode. More than three decades later, farmers ploughing fields and children playing in bamboo thickets accidentally caused the ordnance to explode, which has killed or maimed more than 10,000 people.An internationally funded program to identify potential unexploded ordnance is using targets, map coordinates, and type of ordnance for U.S. bombing runs from two Vietnam air combat databases that cover the years 1965–1975, which the National Archives accessioned in 1976-77. In Laos the data from the bombing runs were entered into a geographic information system that plots the target
coordinates to the bombing database. Maps were then printed and used in the field by bomb technicians who use handheld GPS units to pinpoint the coordinates on the ground via navigational satellites.
What happened to it?
The initial effort was unsuccessful because the geographic coordinates were flawed. The reason for these anomalies is that the data initially were created and used in a report generator system called the National Information Processing System (otherwise known as NIPS). NIPS was developed for the Department of Defense. By the time the records came to the National Archives they were legacy records and the staff on the Machine Readable Archives Division began a process of “deNIPSing” the records, that is moving them out of NIPS by reformatting them to a flat-file non-proprietary format in standard EBCDIC. The “de-NIPSed” files are no longer dependent on the NIPS software with which they were created. Instead, as flat files, users can process and ma nipulate them using
widely-available software applications.
Characteristics of the recovery
For 25 years it was believed that the “deNIPSed” files were trustworthy reformatted records. However, the data anomalies found in the Combat Activities File raised a question. It now appears that at the time the “deNIPSing” occurred, the documentation accompanying the data file either was incomplete or perhaps even missing, because the geographic coordinates, which were encoded in binary (binary angular measurement, a form of “packing data”) in order to conserve space, were incorrectly treated as 7-bit ASCII in each data field. Consequently, all of the geographic coordinates were wrong. Once this problem was identified, a process was begun to correctly convert these data fields.
Cost of the recovery
It has been impossible to find information about the overall cost of the recovery.
Conclusions
The primary issue here is that migration introduced data anomalies into the records, which were not recognized for almost 25 years. These data anomalies could be corrected because NARA had retained the original NIPS data (that is the original 1 and 0s) and periodically migrated them to new media so that they remained “alive” or readable. The lesson to be learned here is the advantage of keeping the original bit stream alive.
Source: Preservation of digital memories: risks and emergencies
Six case studies Edited by Alessandra Ruggiero . http://www.iccu.sbn.it/opencms/export/sites/iccu/documenti/emergenze.pdf p.35-36