1970’s Scanning Development by the NBS with the DEC PDP-11/20
The PDP-11/20 computer's function was as the driver to a microfilm scanner, one in a family called FOSDIC, an acronym for Film Optical Sensing Device for Input to Computers. The first device of its type was developed in the early 1950’s by the National Bureau of Standards (NBS, now NIST) , for the Census Bureau’s large-scale data entry in decennial censuses. The PDP-11 came along fifteen years later for use in the system shown here, named FOSDIC VI.
On the FOSDIC VI system, the scanning CRT and sensor were installed on an otherwise conventional microfilm reader. That’s the device at the far left of the photo. The film moved between the scanning CRT and the photo-detector, each encased in black boxes below the microfilm screen.
A FOSDIC system consisted of a microfilm scanner directed by some kind of computer. The instruments, of which 12 models were made in all, were interactive flying-spot scanners. "Flying-spot" means to guide the scanning according to what it "sees". Typical scanned images included census documents, punched tabulating cards and a variety of special applications. Outputs were normally supplied on magnetic tapes to large-scale computers.
Projects for FOSDIC IV included scanning daily pollution charts for the EPA; scanning underwater current meter film charts for NOAA; and testing data entry forms for the Census.
The scanner-PDP 11 combination as described was declared surplus to NBS in 1975, then acquired by the U.S. Postal Service Research Laboratory and converted into the Postal Precision Scanner and used until 1986. The PDP-11/20 acquired by MARCH was used in related systems and experimental work, acquired by the developer, and in 2006 donated by him to MARCH and InfoAge
MARCH - PDP-11/20 Collection
