ASA carriage control characters
Encyclopedia
ASA control characters are simple printing command characters used by mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

 printers
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...

 to control the movement of paper through line printer
Line printer
The line printer is a form of high speed impact printer in which one line of type is printed at a time. They are mostly associated with the early days of computing, but the technology is still in use...

s. These commands are presented as special characters in the first column of each text line to be printed
Print job
In computing, a print job is a file or set of files that has been submitted to be printed.Jobs are typically identified by a unique number, and are assigned to a particular destination, usually a printer...

, and affect how the paper is advanced before the line is printed.

"ASA" is the abbreviation of the American Standards Association, a former name for the American National Standards Institute
American National Standards Institute
The American National Standards Institute 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 organization also coordinates U.S. standards with international...

 (ANSI), which is believed to have sanctioned these control characters.

Operation

ASA Character Action ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

 Equivalent
1 Advance to next page (form feed
Page Break
A page break is a marker in an electronic document that tells the document interpreter that the content which follows is part of a new page. A page break causes a form feed to be sent to the printer during spooling of the document to the printer.-Form feed:...

)
CR
Carriage return
Carriage return, often shortened to return, refers to a control character or mechanism used to start a new line of text.Originally, the term "carriage return" referred to a mechanism or lever on a typewriter...

 FF
2–9, A, B, C Advance to vertical tab stop CR VT (approximately)
blank Advance 1 line (single spacing) CR LF
0 Advance 2 lines (double spacing) CR LF LF
- Advance 3 lines (triple spacing) CR LF LF LF
+ Do not advance any lines before printing,
overstrike the previous line
CR


Overstriking
Overstrike
In typography, overstrike is a method of printing characters that are missing from the printer's character set. It was widely used around the early 1990s...

 can be used to make boldface text by printing the same line twice without advancing the paper. It can also be used to make underline
Underline
An underline, also called an underscore, is one or more horizontal lines immediately below a portion of writing. Single, and occasionally double , underlining was originally used in hand-written or typewritten documents to emphasise text...

d text by printing a line of underscore
Underscore
The underscore [ _ ] is a character that originally appeared on the typewriter and was primarily used to underline words...

 characters atop the text.

Mainframe printers have 12 channels (1 through 9 and A through C) that can be assigned a fixed position on the page, allowing the printer to skip a variable distance down the page to a fixed location. Normally only channel 1 is preassigned, to the top of the page.

ASA carriage control characters are still used for printer output from mainframe
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

 applications and software today, and are not limited to seasoned software or applications dating from the days of the line printer. ASA carriage control characters are interpreted by other software before being printed on modern computer printer
Computer printer
In computing, a printer is a peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. Many printers are primarily used as local peripherals, and are attached by a printer cable or, in most new printers, a...

s.

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 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 the 7th line

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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