A computer punched card reader or just computer card reader is a

computer input device In computing, an input device is a piece of equipment used to provide data and control signals to an information processing system, such as a computer or information appliance. Examples of input devices include keyboards, mouse, scanners, cameras ...

used to read

computer programs A computer program is a sequence or set of instructions in a programming language for a computer to execute. Computer programs are one component of software, which also includes documentation and other intangible components. A computer progra ...

in either source or executable form and

data In the pursuit of knowledge, data (; ) is a collection of discrete values that convey information, describing quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpret ...

from

punched cards A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...

. A computer card punch is a computer output device that punches holes in cards. Sometimes computer punch card readers were combined with computer card punches and, later, other devices to form multifunction machines. It is a input device and also an output device. Most early computers, such as the

ENIAC ENIAC (; Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer, completed in 1945. There were other computers that had these features, but the ENIAC had all of them in one pac ...

, and the IBM NORC, provided for punched card input/output. Card readers and punches, either connected to computers or in

off-line In computer technology and telecommunications, online indicates a state of connectivity and offline indicates a disconnected state. In modern terminology, this usually refers to an Internet connection, but (especially when expressed "on line" ...

card to/from

magnetic tape Magnetic tape is a medium for magnetic storage made of a thin, magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany in 1928, based on the earlier magnetic wire recording from Denmark. Devices that use mag ...

configurations, were ubiquitous through the mid-1970s. Punched cards had been in use since the 1890s; their technology was mature and reliable. Card readers and punches developed for punched card machines were readily adaptable for computer use. Businesses were familiar with storing data on punched cards and

keypunch A keypunch is a device for precisely punching holes into stiff paper cards at specific locations as determined by keys struck by a human operator. Other devices included here for that same function include the gang punch, the pantograph punch, ...

machines were widely employed. Punched cards were a better fit than other 1950s technologies, such as

, for some computer applications as individual cards could easily be updated without having to access a computer.

Operation

The standard measure of speed is ''cards per minute'', abbreviated CPM: The number of cards which can be read or punched in one minute. Card reader models vary from 300 to around 2,000 CPM. If all columns of an 80 column card encode information this translates to approximately 2,500 characters per second (CPS). '' ow? 80 × 300 = 2400, 80 × 2 000 = 160 000' Cards may be read using mechanical ''brushes'' that make an electrical contact for a hole, and no contact if no punch, or photoelectric sensors that function similarly. Timing relates the signals to the position on the card. Cards may be read serially, column by column, or in parallel, row by row. Card punches necessarily run more slowly to allow for the mechanical action of punching, up to around 300 CPM or 400 characters per second. Some card devices offer the ability to ''interpret'', or print a line on the card displaying the data that is punched. Typically this slows down the punch operation. Many punches read the card just punched and compare its actual contents to the original data punched, to protect against punch errors. Some devices allow data to be read from a card and additional information to be punched into the same card. Readers and punches include a ''hopper'' for input cards and one or more ''stackers'' for cards read or punched. A function called ''stacker select'' allows the controlling computer to choose which stacker a card just read or punched will be placed into.

Card readers/punches

Control Data Corporation

* CDC 405 —

CDC 6000 series The CDC 6000 series is a discontinued family of mainframe computers manufactured by Control Data Corporation in the 1960s. It consisted of the CDC 6200, CDC 6300, CDC 6400, CDC 6500, CDC 6600 and CDC 6700 computers, which were all extremely rapid ...

card reader, 1200 or 1600 cards per minute (CPM) * CDC 415 —

card punch, 250 cards per minute

Documation

Documation Inc. Documation was an American Stock Exchange-listed computer hardware manufacturer founded in 1969 in Melbourne, Florida that went public in 1976. They made ( punched card) card readers used in some American elections 3 decades later. They also ...

, of Melbourne, Florida, made card readers for

minicomputer A minicomputer, or colloquially mini, is a class of smaller general purpose computers that developed in the mid-1960s and sold at a much lower price than mainframe and mid-size computers from IBM and its direct competitors. In a 1970 survey, ...

s in the 1970s: * M-200 card reader, 300 cards/minute also sold by DEC as the CR-11 card reader for the

PDP-11 The PDP-11 is a series of 16-bit minicomputers sold by Digital Equipment Corporation (DEC) from 1970 into the 1990s, one of a set of products in the Programmed Data Processor (PDP) series. In total, around 600,000 PDP-11s of all models were so ...

* M-600 card reader, 600 cards/minute, also sold by HP as 2892A and 2893A * M-1000-L card reader 1,000 cards/minute Their card readers have been used in elections, including the 2000 "Chads" election in Florida.

IBM

* IBM 711 card reader computer peripheral used in the vacuum tube era, 150 or 250 CPM * IBM 2501 card reader, 600 or 1000 CPM * IBM 1402 high speed reader/punch introduced with the

IBM 1401 The IBM 1401 is a variable-wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing unit record equipment for processing data stored on pu ...

, 800 CPM * IBM 1442 reader/punch introduced with the lower-cost IBM 1440, read 80-400 CPM, punch 91-355 CPM * IBM 2540 reader/punch derived from the 1402 that was introduced with System 360 * IBM 2560 Multi-Function Card Machine (MFCM), first introduced for the

IBM System/360 Model 20 The IBM System/360 Model 20 is the smallest member of the IBM System/360 family announced in November 1964. The Model 20 supports only a subset of the System/360 instruction set, with binary numbers limited to 16 bits and no floating point. In ...

, could also collate, sort and print/interpret. * IBM 3505 reader and its companion 3525 reader/printer/punch that was introduced for the

System/370 The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path f ...

in 1971, read 1200 CPM, punch 300 CPM

Binary format

For some computer applications, binary formats were used, where each hole represented a single binary digit (or "

bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented a ...

"), every column (or row) is treated as a simple bitfield, and every combination of holes is permitted. For example, the IBM 711 card reader used with the 704/709/7090/7094 series scientific computers treated every row as two 36-bit words, ignoring 8 columns. (The specific 72 columns used were selectable using a plugboard control panel, which is almost always wired to select columns 1–72.) Sometimes the ignored columns (usually 73–80) were used to contain a sequence number for each card, so the card deck could be sorted to the correct order in case it was dropped. An alternative format, used by the

IBM 704 The IBM 704 is a large digital mainframe computer introduced by IBM in 1954. It was the first mass-produced computer with hardware for floating-point arithmetic. The IBM 704 ''Manual of operation'' states: The type 704 Electronic Data-Proc ...

's IBM 714 native card reader, is referred to as Column Binary or Chinese Binary, and used 3 columns for each 36-bit word. Later computers, such as the

IBM 1130 The IBM 1130 Computing System, introduced in 1965, was IBM's least expensive computer at that time. A binary 16-bit machine, it was marketed to price-sensitive, computing-intensive technical markets, like education and engineering, succeeding t ...

System/360 The IBM System/360 (S/360) is a family of mainframe computer systems that was announced by IBM on April 7, 1964, and delivered between 1965 and 1978. It was the first family of computers designed to cover both commercial and scientific applic ...

, used every column. The

's card reader could be used in Column Binary mode, which stored two characters in every column, or one 36-bit word in three columns when used as input device for other computers. However, most of the older card punches were not intended to punch more than 3 holes in a column. The ''multipunch'' key is used to produce binary cards, or other characters not on the keyboard. IBM lace card

As a

prank A practical joke, or prank, is a mischievous trick played on someone, generally causing the victim to experience embarrassment, perplexity, confusion, or discomfort.Marsh, Moira. 2015. ''Practically Joking''. Logan: Utah State University Press. ...

, in binary mode, cards could be punched where every possible punch position had a hole. Such " lace cards" lacked structural strength, and would frequently buckle and jam inside the machine.

References

Punched card equipment

File:IBM 650 at Texas A&M.jpg, An IBM 650 computer, introduced in 1953, came with the IBM 533 Card Reader/Punch, right. At many IBM 650 installations, punched cards and address 8000 on the console were the only input and output medium. File:IBM Electronic Data Processing Machine - GPN-2000-001881.jpg, IBM 711 card reader on an IBM 704 computer at NASA in 1957 File:BRL61-IBM 1401.jpg, The popular IBM 1401, introduced in 1959 featured a fast card reader/punch, the IBM 1402, left File:NASAComputerRoom7090.NARA.jpg, IBM 711 card readers, far left and foreground, attached to dual IBM 7090s at NASA Mission Control in 1962. File:IBM 2314 DiskDrives and IBM 2540 CardReader Punch.jpg, An IBM 2540 Card Reader Punch at the University of Michigan computer center in 1968 File:DM IBM S360.jpg, Punched card reader/punch on an IBM System/360 Model 20 File:IBM System3 model 10d.jpg, IBM System/3, announced in 1969 introduced a new, smaller punched card and a combined reader/punch/sorter, right File:IBM 7070 (7074).jpg, IBM 7070 with IBM 7501 Console Card Reader, right, based in the IBM 026 keypunch File:Documation card reader.JPG, Documation M-600 card reader {{DEFAULTSORT:Punched card input output Punched card Computing input devices Computing output devices Computing-related lists