IBM 1130 with IBM 1132 printer open (7415892502)

The IBM 1132

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 ...

was the normal printer for 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 th ...

computer system. It printed 120 character lines at 80 lines per minute. The character set consisted of numbers, upper-case letters and some special characters. The 1965-introduced 1132 was built around a stripped down

IBM 407 The IBM 407 Accounting Machine, introduced in 1949, was one of a long line of IBM tabulating machines dating back to the days of Herman Hollerith. It had a card reader and printer; a summary punch could be attached. Processing was directed by ...

printing mechanism. The 407 was IBM's top-of-the-line

accounting machine An accounting machine, or bookkeeping machine or recording-adder, was generally a calculator and printer combination tailored for a specific commercial activity such as billing, payroll, or ledger. Accounting machines were widespread from the ear ...

from the 1950s. The 1130 had 120 power

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch e ...

s, each wired to the print magnet for one printer column. The magnet released a lever that engaged a cam with a spinning clutch shaft. The engaged cam then made one revolution, pushing its print wheel toward the ribbon and paper, thereby printing one character. As the set of 120 print wheels spun, the 1130 received an

interrupt In digital computers, an interrupt (sometimes referred to as a trap) is a request for the processor to ''interrupt'' currently executing code (when permitted), so that the event can be processed in a timely manner. If the request is accepted, ...

as each of the possible 48 characters was about to move into position. The printing driver software had to quickly output a 120 bit vector designating which transistors were to fire so as to drive the print wheel against the ribbon and paper. This put a big performance burden on the CPU, but resulted in an inexpensive (for the time) printer. Sometimes a printer output line transistor would fail, resulting in a blank print position. If you knew your way around inside the 1130, it was possible to swap circuit cards so as to move the bad print position to near the right end of the printed line. This kept the 1130 usable until the repair person showed up. The 1132 came in two models with the following characteristics:Model 1 @ 80 Lines/minute, Model 2 @ 40 LPM: * Standard 48-character-set typewheels with A..Z, 0..9 and the symbols . , + - * / = ( ) ' $ &. * Model 1 prints up to 80 alphameric or 110 numeric lines per minute and can be attached to 1131 CPU Models 1, 2, 3, and 5. * Model 2 prints up to 40 alphameric or 55 numeric lines per minute and may be attached only to the 1131 CPU Model 4. * Standard 120 print-line positions spaced 10 characters per inch. * Operator selection of vertical line spacing, 6 or 8 lines per inch. * Forms skipping under program control through automatic, paper-tape-controlled carriage. * Printer operation under stored-program control through automatic interrupt system. * Direct connection to the 1131 Central Processing Unit by means of the 1132 Printer Attachment and an Expansion Adapter.

References

* http://bitsavers.org/pdf/ibm/1130/functional_characteristics/A26-5881-3_1130_Functional_Characteristics.pdf p.45ff
Ed Thelen history site, includes photo

IBM 1132 Field Engineering Theory of Operation (Manual of Instruction)
IBM 227-3622, IBM, 1965

External links

Image of an 1132 on Flickr
{{IBM midrange computers 1132 Line printers 1132