ASA control characters are simple printing command characters used to control the movement of paper through
line printer
A line printer prints one entire line of text before advancing to another line. Most early line printers were
impact printers.
Line printers are mostly associated with unit record equipment and the early days of digital computing, but the ...
s. These commands are presented as special characters in the first column of each text line to be
printed
Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The e ...
, and affect how the paper is advanced before the line is printed. The remainder of the line is printed starting in the first printable position.
"ASA" is the abbreviation of the American Standards Association, a former name for the
American National Standards Institute
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The orga ...
(ANSI), which has standardized these control characters in ''ANSI X3.78-1981(R1992) representation of vertical carriage positioning characters in information interchange''. These are also called "FORTRAN control characters" because they first appeared in versions of
FORTRAN II in the early 1960s,
although they have since been used by other programming languages such as
COBOL
COBOL (; an acronym for "common business-oriented language") is a compiled English-like computer programming language designed for business use. It is an imperative, procedural and, since 2002, object-oriented language. COBOL is primarily u ...
and
PL/I
PL/I (Programming Language One, pronounced and sometimes written PL/1) is a procedural, imperative computer programming language developed and published by IBM. It is designed for scientific, engineering, business and system programming. I ...
.
Operation
Overstriking can be used to make
boldface
In typography, emphasis is the strengthening of words in a text with a font in a different style from the rest of the text, to highlight them. It is the equivalent of prosody stress in speech.
Methods and use
The most common methods in W ...
text by printing the same line twice without advancing the paper. It can also be used to make
underline
An underscore, ; also called an underline, low line, or low dash; is a line drawn under a segment of text. In proofreading, underscoring is a convention that says "set this text in italic type", traditionally used on manuscript or typescript as ...
d text by printing a line containing
underscore
An underscore, ; also called an underline, low line, or low dash; is a line drawn under a segment of text. In proofreading, underscoring is a convention that says "set this text in italic type", traditionally used on manuscript or typescript ...
characters in the print positions occupied by the text to be underscored.
Mainframe printers originally had a
carriage control tape
A carriage control tape was a loop of punched tape that was used to synchronize rapid vertical page movement in most IBM and many other line printer
A line printer prints one entire line of text before advancing to another line. Most ear ...
, with 12 channels (1–9, A, B, C) that can be assigned a fixed position on the page by punching a hole, allowing the printer to skip a variable distance down the page to a fixed location. Later printers such as the
IBM 3211 and
IBM 4248 did away with the physical carriage control tape and used an electronic ''Forms Control Buffer'' (FCB) instead.
ASA carriage control characters are still used for printer output from
mainframe
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise ...
applications and software today. They are interpreted by drivers and other software before being printed on modern printers.
Example output containing ASA carriage control characters:
This is the first line on the page
This is the third line on the page
This is the 6th line on the page
This is the 7th line on the page
____ the - Overstrike and boldface the 7th line
Example as printed output:
This is the first line on the page
This is the third line on the page
This is the 6th line on the page
This is the 7th line on the page - Overstrike and boldface the 7th line
See also
*
Carriage control tape
A carriage control tape was a loop of punched tape that was used to synchronize rapid vertical page movement in most IBM and many other line printer
A line printer prints one entire line of text before advancing to another line. Most ear ...
*
IBM Machine Code Printer Control Characters
References
External links
* More elaborate description a
Felgall Mainframe*
* First-character forms-control data definitio
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Computer printers
Control characters