Once common words no longer heard . . .

More and More Obsolete Computing Terms

©Conrad Weisert, Information Disciplines, Inc.,
30 November 2016

Those of us who've been in the computing / data-processing field for some time, are noticing that many professional and technical terms that we once used every day are rarely heard these days. Younger colleagues are sometimes puzzled upon hearing or reading some of those terms.

I'm starting this little collection, therefore, to remind readers how much our profession has changed just within a few decades, and perhaps also to help clarify old documentation.

Register used for calculations. (replaced by multiple general registers)

Information represented in BCI or EBCDIC characters.

Binary-coded information, a 6-bit character representation (sometimes BCD, binary-coded decimal) derived from punched-card codes.

Same as physical record.

card image
(a) Character string representing the contents of an 80-column punched card.
(b) Bit array (usually 12 X 72) with 1's representing holes in a punched card.

core dump
Printed contents of main memory or a part of main memory, used as a debugging aid.

carriage tape
A perforated paper loop used to control rapid vertical movement of continuous paper in a line printer.

drum card
A punched card used to control an IBM keypunch machine to advance to the beginning of each field, default to certain character types within the field, duplicate a field from the previous card, etc., in order to enhance the speed and accuracy of offline batch data entry.

An 8-bit extension of BCI used by IBM 360 and other third-generation computers; replaced by ASCII.

Encoding scheme for representing letters, digits, and punctuation as holes on a punched card. Sometimes casually used as a synonym for BCI.

index reigister
Register used mainly for address modification or counting rather than general computation.

JCL (Job Control Language)
Command language for batch processing on OS/360 and similar batch operating systems.

(instruction) Same as branch; used in Univac and CDC computer architectures.

logical record
Contiguous data items written to or read from a file as a unit.

(a). Supervisory control program in an opeating system.
(b). Screen display device.

object deck
Punched card output from a compiler or assembler containing object code in absolute or relocatable form.

overpunched sign
Punched card representation of a plus sign or a minus sign in the same column with a digit to conserve space. The result was often the same code as an alphabetic character, relying on program logic to make the distinction.

packed decimal
Numeric representation using 4 bits for each decimal digit (i.e. 2 digits per byte), supported by IBM 360 and similar computers.

A temporary usually emergency program correction.

physical record
Contiguous logical records written to or read from a magnetic tape or disk as a unit, in order to reduce the space between records.

relocatable binary
Compiler output (object deck) in which a loader program would increment certain fields (memory addresses) by the actual origin of the program component in memory.

source deck
Punched cards containing characters comprising a module in a programming language; input to a compiler or assembler.

(instruction) Same as branch; used in IBM scientific computer architectures.

word mark
Bit position reserved for separating data items (words) on variable-word-length machines, such as the IBM 1401.

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Historical notes

Last modified 27 January 2017