Keypunch
| Industry | Computer hardware |
|---|---|
| Founded | 1911 |
| Headquarters | Armonk, New York , United States |
| Products | Keypunch machines, punched card equipment |
| Website | www |
A keypunch refers to a device designed to create holes in rigid paper cards at precise points dictated by keys pressed by an operator. Comparable equipment includes the gang punch, pantograph punch, and stamp. The term also encompasses machines that transfer information onto punched tape media.
In the context of Jacquard looms, punched cards acted as a paper tape "chain" containing a program that controlled the loom's functions.[1]
For Hollerith machines and similar unit record devices, punched cards held the data these machines processed. In computer systems utilizing punched card input/output, such cards represented either data or programs directing the machine’s operations.
Initial Hollerith keypunches operated manually; subsequent versions were electromechanical units resembling compact desks with keyboards akin to typewriters, featuring hoppers for blank cards and stackers for completed punched cards. Certain models also printed the character corresponding to the punched holes above each column. The discarded punched pieces, known as chad, were collected in a chad box, or at IBM facilities called a chip box or bit bucket.
In numerous data processing scenarios, punched cards underwent verification by re-entering the same information (referred to as two pass verification). This process created significant employment opportunities for keypunch operators, predominantly women,[2] who were typically employed full-time within extensive keypunch departments responsible for data input.
During the 1950s, Remington Rand launched the UNITYPER, which allowed direct data entry onto magnetic tape for use with UNIVAC systems. Later in 1965, Mohawk Data Sciences introduced an enhanced magnetic tape encoder marketed as a substitute for keypunch machines. The emergence of microprocessors and cost-effective computer terminals encouraged smaller firms such as Inforex and Pertec to develop key-to-tape and key-to-disk solutions.[3]
Throughout the 1970s, keypunches and punched cards remained widely used but were rapidly superseded by affordable CRT computer terminals. Eliminating the intermediate step of transferring punched cards to tape or disk lowered expenses and enhanced data verification and correction during entry. The introduction of video display terminals, interactive timeshared systems, and eventually personal computers allowed original users to input data and programs directly rather than relying on keypunch operators.
Stamping Jacquard cards, 1801 through 1890
Jacquard cards were originally created by hand stamping or cutting, occasionally with the aid of a guide plate. A refinement involved sandwiching the card between two perforated metal plates, inserting punches according to the design, and then pressing the assembly through a press. These manual techniques were eventually replaced by mechanized methods. The so-called 'Piano machines,' named for their keyboard-like keys and similar in function to unit record keypunches, became the predominant technology.
Hollerith and IBM Keypunch Machines, 1890s to 1930s
The initial card punch devised by Herman Hollerith in the 1890s was a straightforward device that created circular holes measuring 3/16 inch in diameter. To simplify the punching process, these holes were positioned close to the edges of the cards. Hollerith later advanced this concept by inventing a more precise Keyboard Punch, which employed a pantograph mechanism connecting a punch tool to a pointer, enabling accurate alignment over a 12 by 20 grid for manual hole placement within one of 20 columns.
In 1901, Hollerith secured a patent for a device where an operator could press one of twelve keys to punch a hole, with automatic card feeding following each punch. This initial Type 001 keypunch utilized 45-column cards with round holes. By 1923, The Tabulating Machine Company launched the first electrically powered keypunch, the Type 011 Electric Keypunch, which activated a solenoid to create holes when keys closed electrical circuits. The 80-column punched card format made its debut in 1928. Subsequent models included the Type 016 Motor-Driven Electric Duplicating Keypunch (1929), Type 31 Alphabetical Duplicating Punch (1933), and Type 32 Alphabetical Printing Punch (1933).
"Alphabetical duplicating keypunches captured alphabetic data on tabulating cards so that full words and names, alongside numeric information, could be printed later using an alphabetical accounting machine. The Type 31 Alphabetical Duplicating Punch (1933) automatically ejected one card and fed the next within 0.65 seconds. These devices featured distinct alphabetical and numerical keyboards; the alphabetical keyboard resembled a manual typewriter but omitted shift, tab, backspace, and character keys, instead incorporating skip, release, stacker, and '1' keys." – IBM Archives
Post-World War II IBM Keypunches and Verifiers for 80-Column Cards
A majority of IBM keypunches and verifiers shared an electromechanical keyboard design that encoded keystrokes by means of mechanical bails closing electrical contacts upon key depression. This action generated encoded signals representing characters. A feedback loop energized magnets to return the keystem to its resting position, reset encoding bails, and provide tactile as well as audible confirmation to the operator. Each unit developed its own unique tactile response influenced by wear and contact adjustments; however, no direct "feel" modifications existed beyond calibrating electrical contacts. Special function keys operated solely through electrical means without mechanical linkages.
Models like the IBM 024, 026, and 029 accepted program cards that controlled features such as tabbing and field duplication. The more advanced IBM 129 incorporated electronic circuit cards allowing operators to store simple programs.
IBM 024 and 026 Card Punch Models
Released in 1949, both the IBM 024 Card Punch and IBM 026 Printing Card Punch were fundamentally similar except that the latter included printing capabilities. Each machine contained twelve precision punches—one assigned per card row—powered by robust actuators. Cards were advanced one column at a time as holes were punched, producing a characteristic "chunk" noise during operation. These machines accommodated cards with 51, 60, 66, and 80 columns.
The IBM 026 model printed characters above each punched column. By 1964, ten variants existed featuring different character sets; scientific versions replaced less frequently used commercial symbols with parentheses, equal signs, and plus signs.
Their logic circuits integrated diodes, 25L6 vacuum tubes, and relay components. The vacuum tube circuits operated mainly at 150 VDC for punch-clutch magnet control; most other circuitry functioned at 48 VDC.
Character printing was achieved through a 5×7 dot matrix wire array regulated by a metal "code plate" embedded with precisely machined pins representing each printable symbol. When pressed against the wire array, selected wires engaged to imprint characters onto ribbon and card. This mechanism was intricate to service; broken wires inside narrow tubes were common faults requiring meticulous repair. The printing assembly was susceptible to damage when duplicating unconventional "binary" punch patterns that forced the code plate beyond its intended range. Disabling printing merely prevented pin impact but did not disengage the code plate from the punching mechanism.
The external styling of the IBM 024/026 punches was designed by renowned industrial designer Raymond Loewy, famous for his streamlined aesthetics and early-to-mid twentieth century railway car designs. The machines’ heavy steel bodies with rounded edges exemplified an industrial Art Deco influence.
IBM 056 Card Verifier
The IBM 056 served as the verification counterpart to the 024 Card Punch and the 026 Printing Card Punch. It bore a strong resemblance to the 026 keypunch, distinguished primarily by a red error indicator lens mounted on its cover. During operation, the verifier user would re-enter the identical data keyed in by the punch operator, allowing the machine to perform a comparison to ensure the punched information matched. Cards that passed verification were marked with a small notch along their right edge.
Most mechanical and electrical parts of the IBM 056 were shared with the 024/026 keypunch models; however, its punching mechanism was replaced by sensing pins designed to detect holes. If any inconsistencies were found, these pins halted card movement and activated a red error light. Instead of printing, the notching mechanism driven by solenoids took the place of the 026’s print assembly.
Operators were given up to three chances to amend errors during verification. Failing that, an error notch was punched above the column containing the fault, and the "OK" punch function was disabled. While some data might still be accurate, this procedure significantly reduced repeated mistakes. Because some operators could anticipate errors based on previous entries, certain machines were altered to permit only a single input before triggering error notching.
Cards flagged with error notches underwent re-punching on an 024 or 026 device by duplicating correct columns and correcting mistakes prior to re-verification and final approval notching. The duplication feature replicated existing hole patterns onto blank cards, simplifying the correction workflow.
Typewriter Card Punches
The initial integration of a card punch with a typewriter—enabling text typed on a keyboard to be punched directly onto cards—was developed by Powers in 1925. IBM later introduced the IBM 824 Typewriter Card Punch, which replaced the traditional 024 keyboard with an electric typewriter unit. Similarly, the IBM 826 combined an IBM 026 Keypunch mechanism with a typewriter interface.
IBM 029 Card Punch
Launched alongside System/360 in 1964, the IBM 029 incorporated new character encodings for symbols such as parentheses, equals sign, plus sign, and others within the EBCDIC character set. Mechanically akin to the IBM 026, it printed characters corresponding to punched data at the top of each card using an expanded code plate featuring 2240 printing-pin locations to support EBCDIC’s broader range of characters.
Its logic circuitry utilized wire contact relays in later iterations and reed relays combined with diodes mounted on SMS cards in earlier versions. Due to reliability concerns with reed relays, IBM reverted to wire-contact relay designs. Operating at 48 volts DC, this model eliminated vacuum tubes found in predecessors like the 024 and 026. An optional "Left-Zero" capability automatically inserted leading zeros to right-justify numeric fields, improving data entry efficiency.
IBM 5924 Key Punch
The IBM 5924 Key Punch, derived from the model T01 of the IBM 029 series, debuted during IBM’s 1971 announcement of the IBM Kanji System. It featured a unique keyboard layout that allowed operators to utilize fifteen shift keys with their left hand while selecting among 240 Kanji characters with their right hand. This design supported processing extensive East Asian character sets exceeding 10,000 symbols used in Chinese, Japanese, and Korean computing applications.
IBM 059 Card Verifier
The IBM 059 Verifier served as a companion to the IBM 029 Card Punch but marked a notable departure from its forerunner, the IBM 056. Instead of relying on mechanical sensing pins, it employed optical detection of punched holes through fiber-optic lightpipes illuminated by a single light source, resulting in significantly quieter operation. Despite this modern sensing approach, the fundamental verification technique closely resembled that of the 056 model.
Interestingly, some users missed the distinct audible "thunk" characteristic of the earlier device. This absence occasionally led operators to press keys more forcefully, sometimes accelerating wear on the keyboard—an example of how users adapted to evolving technology with mixed effects.
IBM 129 Card Data Recorder
Released alongside the System/370 in 1971, the IBM 129 integrated punching, verification, and online 80-column card reading/punching capabilities for compatible computer systems. A toggle switch on its keyboard allowed users to switch between punch and verify modes.
Featuring transistorized electronics, the IBM 129’s primary innovation over previous IBM keypunch models was its electronic buffer for 80 columns. This buffer permitted error correction using the Backspace key before automatically punching the entire card upon pressing Release. Earlier machines required manual card ejection and correction after mistakes.
Its logic circuits were housed within SLT modules mounted on a swing-out, wire-wrapped backplane. The card punching speed operated independently from keystroke input speed, improving overall throughput.
The device could hold up to six different programs selectable via a rotary dial. Unlike earlier models that loaded programs from a drum, program cards were fed through the card path. Duplication processes used stored images rather than separate read stations, facilitated by an integrated optical reader enabling "read-in" operations.
Program card
IBM keypunches such as the 024, 026, and 029 along with verifiers like the 056 and 059 utilized Program Cards or drum cards to automate tasks including field skipping, default character insertion, and duplication—advancing beyond earlier Skip Bars. These programs were encoded on punched cards wrapped around a rotating drum; holes engaged electrical contacts through starwheels as cards passed through.
Programming employed the top six rows [12,11,0,1,2,3], with an optional Second Program feature using the bottom six rows [4,5,6,7,8,9], selectable by a switch. The program drum could be removed by releasing a locking lever.
Functions provided by program cards included:
| Function | #1 | Char. | #2 | Char. | Description |
|---|---|---|---|---|---|
| Field Definition | 12 | & | 4 | 4 | Punch all columns except first within a field |
| Start Automatic Skip | 11 | - | 5 | 5 | Punch first column of fields designated for skipping |
| Start Automatic Duplication | 0 | 0 | 6 | 6 | Punch first column of fields set for duplication |
| Alphabetic Shift | 1 | 1 | 7 | 7 | Switch keyboard to Alphabetic mode in specified column |
| Left Zero Print | 2 | 2 | 8 | 8 | Force printing of leading zeros or signs |
| Print Suppression | 3 | 3 | 9 | 9 | Prevent printing in targeted column |
Programming languages such as FORTRAN, RPG, and IBM’s Assembly language assigned specific operations to particular columns (for example: columns 1,10,16,36,72). Program cards automated tabbing and defined fields accordingly.
An illustrative example:
1.......10........20........30........40........50........60........70........80 1AAAAAAAA1AAAAA1AAAAAAAAAAAAAAAAAAA1AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA &&&&&&&&
Here, activating skip would move the cursor directly to column 10. Fields marked as "Numeric Shift" often contained special symbols or sequence numbers.
Note that "Field Definition" (code 12) and "Alphabetic Shift" (code 1) print as A. Improper use of program code 2 could generate invalid characters or even damage printers.
Additionally, program cards supported "gang punching," allowing fixed fields to be inserted across multiple card decks simultaneously. Some operators even programmed rhythmic patterns for entertainment by alternating between noisy and silent characters during punching.
IBM 5496 Data Recorder for 96-Column Cards
In 1969, IBM introduced the System/3 series of entry-level business computers that utilized a more compact 96-column punched card. To support these cards, IBM developed the IBM 5496 Data Recorder, a keypunch machine equipped with printing and verification capabilities, alongside the IBM 5486 Card Sorter designed specifically for processing these cards.
Powers and Remington Rand (UNIVAC) Keypunch Machines
Around 1906, James Powers, working at the United States Census Bureau, created the Powers Keypunch, featuring 240 keys tailored for census data entry. Powers established the Powers Accounting Machine Company in 1911, which was later acquired by Remington Rand in 1927. Remington Rand's UNIVAC division manufactured keypunch devices compatible with their 90-column cards as well as machines designed to work with IBM’s 80-column cards. Their mechanical design avoided infringing on IBM patents prior to acquiring Eckert–Mauchly Computer Corporation. UNIVAC keypunches processed the entire card data before punching holes in a single operation, allowing for error correction and minimizing card waste.
Remington Rand’s lineup included models such as the UNIVAC Card Code Punch Type 306-5 (90 Column Alphabetical), Types 204-2 and 204-3 (90 Column Numerical), Portable Electric Punch Type 202, Spot Punch Type 301, and Automatic Verifying Machine Type 313.
The Type 306-2 model facilitated verification by running cards through the keypunch twice; correctly punched data produced elongated holes while mistakes appeared as round perforations. The Automatic Verifying Machine provided rapid mechanical error detection. In 1969, the UNIVAC 1710 Verifying Interpreting Punch was introduced to further enhance accuracy.
Keypunch as a Verb
The expression keypunched (from the verb to keypunch) initially described the process of transferring information onto punched cards using a keypunch device. Although physical keypunch machines have become obsolete, the term endures as a synonym for data entry.
This evolution reflects a change from its original function: pressing a key on a keypunch simultaneously imprinted the character on the card's surface and punched holes readable by a computer Card reader.
Shift Toward Direct Data Input
During the 1950s, Remington Rand unveiled the UNITYPER, an input device that allowed direct data entry onto magnetic tape for use with UNIVAC systems. Subsequently, in 1965, Mohawk Data Sciences introduced an enhanced magnetic tape encoder marketed as a keypunch alternative. By the mid-1970s, advancements in microprocessors and affordable computer terminals led smaller companies like Inforex and Pertec to develop new key-to-tape and key-to-disk input solutions.
While punched cards continued to be widely used for data input and programming through the mid-1980s, removing the intermediate step of transferring data from cards to tape or disk lowered expenses and improved error detection during entry. The advent of video display terminals, interactive timeshared systems, and eventually personal computers enabled originators to enter data directly, replacing traditional roles of data entry clerks.
See also
- Punched card
- Punched card input/output
- Hollerith code
- Unit record equipment
- Computer programming in the punched card era
- List of IBM products
- Chad (paper)
Further reading
External links
- Columbia University Computing History: IBM Keypunches
- IBM Archives: IBM 029 — Card Punch
- IBM Archives: Working for the railroad (001 keypunch)
- IBM Punched Card Accounting Machines (1955)
- ↑ Bell, T.F. (1895) Jacquard Weaving and Designing, Longmans, Green And Co.
- ↑ IBM Archive: Keypunch operators, 1934, Stockholm
- ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).