Carriage control tape
Encyclopedia
A carriage control tape was a loop of punched tape
Punched tape
Punched tape or paper tape is an obsolete form of data storage, consisting of a long strip of paper in which holes are punched to store data...

 that was used to synchronize rapid vertical page movement in most IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

 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 from unit record
Unit record equipment
Before the advent of electronic computers, data processing was performed using electromechanical devices called unit record equipment, electric accounting machines or tabulating machines. Unit record machines were as ubiquitous in industry and government in the first half of the twentieth century...

 days through the 1970s. The tape loop was as long as the length of a single page. A pin wheel moved the tape accurately using holes in the center of the tape. A hole punched in one of the other channels represented a particular position on the page. Channel one was typically used to indicate the top of the page and might be the only channel used. Another channel might indicate the summary line on an invoice, enabling rapid skipping to that line. IBM provides a special manual punch that allowed accurate placement of the channel punches. Skipping occurred under computer control, but a form feed switch on the printer control panel allowed a manual skip to the top of the page. The tapes could be easily changed when new, continuously fed forms were loaded into the printer.

Sources

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