The conventions or standards described apply to data on industry compatible magnetic tapes to be made publicly available for the six Count summarizations and the geocode lists of 1970 census data.

Conventions applicable to summary tapes prepared from Dress Rehearsal censuses were established in 1968. Prior to the establishment of those conventions, there were a series of telephone contacts with representatives of computer manufacturers in an attempt to identify the existence of some standards. The only standard that a majority of computer systems share is the FORTRAN formatted READ statement for handling up to 132 characters per physical record in one READ execution.

As specifications for the contents of various summary files became firm, the need for modification to the conventions used for Dress Rehearsal summary tapes became apparent. The modified conventions are contained in this document. The development of geocode files has generally followed the same conventions.