What is a unit record system?

Answer 1

In Computer technology, a unit record system is a data storage system whose architecture descends from early IBM unit record machinery that used (primarily) 80 column punched (Hollerith) cards as the media. A full reference to the history and employment of such machines can be found at the related link.

When electronic digital computers began to displace unit record machinery beginning in the 1950's, the existing data structure of the 80 column card was, in large measure, retained. Even when the media changed from punched card to magnetic tape and disc and record sizes varied from the original 80 character limit, the basic features of the unit record machine data storage system prevailed.

In a unit record system, each fixed length record comprises multiple fixed length attribute fields in a specific order with each field beginning at a known column number. Each field contains character (in some arbitrary encoding scheme) representations of the data associated with each attribute. One field, often the very first or the very last in the unit record, may contain a unit record key value. Where present, a key value may be used by computer programs to distinguish among multiple record types and determine which field mapping to use to associate the correct characters with their respective attributes.

A unit record system has a second distinguishing feature that derives from its storage system. It is invariantly a sequential batch processing system where a data stream of uniformly sized fixed length records are serially processed. The presence of a key field in a unit record allows multiple record types, each employing a unique attribute field collection, to be stored and used together in such a stream. In such fashion, data which belongs together but which exceeds the limits of the maxmum unit record size may be split over several records.

A trivial example of a multi key unit record system would be:

Key: AA

Field_01: Record_key

Size: 02

Field_02: Last_name

Size: 30

Field_03: First_name

Size: 30

Key: BB

Field_01: Record_key

Size: 02

Field_02: Date_of_birth

Size: 08

Field_03: Place_of_birth

Size: 26

Field_04: Country_of_birth

Size: 26

A pair of associated records would look like (the ^ indicates an unpunched column:

AASMITH^^^^^^^^^^^^^^^^^^^^^^^^^ADAM

BB19110315BOSTON^^^^^^^^^^^^^^^^^^^United States of America

The rules for processing these records are what comprise a computer program's logic.

In Education a Unit Record System refers to a centralized repository of student records where the student unit record contains all official documentation relating to an individual's entire educational history. This unified record follows the student from school to school within an educational system and is retained by the originating authority after the student graduates or otherwise leaves its jurisdiction. Typically, unit record systems are limited to a single local school authority (or board) but in many locales they instead exist at the city, province, state or national level.

In Medical Practice, a Unit Record System is a concept of unified patient information wherein all medically significant data relating to a specific individual is available from a single location and is always presented together. This contrasts with the prevailing Split Record System where a given individual may have multiple records kept at numerous repositories such as their family physician, various pharmacies, every hospital that they have ever received treatment at, and the individual practitioner records of any medical specialists to whom they may have been referred.