Monday, 12 December 2011

IBM Selectric typewriter

The IBM Selectric typewriter was a awful acknowledged archetypal band of electric typewriters alien by IBM on July 31, 1961.12

Instead of the "basket" of alone typebars that swung up to bang the award and folio in a acceptable typewriter, the Selectric had a blazon aspect (frequently alleged a "typeball") that rotated and pivoted to the actual position afore striking. The blazon aspect could be calmly afflicted so as to book altered fonts in the aforementioned document, resurrecting a accommodation that had been pioneered by the Blickensderfer typewriter sixty years before. The Selectric additionally replaced the acceptable typewriter's affective carrying with a cardboard roller ("platen") that backward in position while the typeball and award apparatus confused from ancillary to side.

Selectrics and their birth eventually captured 75 percent of the United States bazaar for electric typewriters acclimated in business.3 IBM replaced the Selectric band with the IBM Wheelwriter in 1984 and transferred its typewriter business to the anew formed Lexmark in 1991

Selectric II

After the Selectric II was alien in 1971, the aboriginal architecture was appointed the Selectric I. These machines acclimated the aforementioned 88-character accounting elements. However they differed from anniversary added in abounding respects:

The Selectric II was squarer at the corners, admitting the Selectric I was rounder.

The Selectric II was accessible with a Bifold Angle advantage to acquiesce it to be switched (with a batten at the top larboard of the "carriage") amid 10 and 12 characters per inch, admitting the Selectric I had one anchored "pitch."

The Selectric II had a batten (at the top larboard of the "carriage") that accustomed characters to be confused up to a bisected amplitude to the larboard (for absorption text, or for inserting a chat one appearance best or beneath in abode of a deleted mistake), admitting the Selectric I did not. This advantage was accessible alone on bifold angle models.

The Correcting Selectric II was appear in 1973 and had a alteration feature. This formed in affiliation with a alteration ribbon: Either the cellophane and hardly adhering "Lift-Off" band (for use with Correctable Film ribbons), or the white "Cover-Up" band (for bolt or Tech-3 ribbons).

The white or cellophane alteration band was at the larboard of the typeball and its orange take-up ball at the appropriate of the typeball; it was afflicted apart from the accounting ribbon. The alteration key (an added key at the basal appropriate of the keyboard) backspaced the carrying by one amplitude and additionally put the apparatus in a approach wherein the abutting appearance typed would use the alteration band instead of the accustomed ribbon, and along would not beforehand the carriage. The typist would columnist (and release) the alteration key and again re-type the erroneous character, either appropriation it off of the folio or (if application a bolt ribbon) accoutrement it with white-out powder, again blazon the actual character. Any cardinal of mistakes could be adapted this way, but the action was absolutely manual, as the apparatus had no anamnesis of the typed characters

Selectric-based machines with data storage

In 1964 IBM alien the "Magnetic Band Selectric Typewriter" and in 1969, a "Magnetic Agenda Selectric Typewriter." These were sometimes referred to as the "MT/ST" and "MC/ST", respectively. The MC/ST was additionally accessible in a "communicating" adaptation that could challenge an IBM 2741 terminal or run its built-in Correspondence Code. These featured electronically-interfaced accounting mechanisms and keyboards and a alluring accumulator accessory (either band in a cartridge, or a magnetic-coated agenda the aforementioned admeasurement as an 80-column punched card) for recording, editing, and replaying typed actual at ca. 12-15 characters per second.

These machines were amid the aboriginal to accommodate chat processing adequacy in any form. They acclimated the aforementioned elements as accustomed appointment Selectrics.

In 1972, the "Mag Agenda Executive" was offered. Like IBM's beforehand typebar-based "Executive" models this offered proportional spacing, based on multiples of a 1/60" assemblage size. Unlike the assorted "Selectric Composer" models, there was no accouterment for ambience the apparatus to alter the letter and chat agreement to actualize justified copy. Some of the typestyles originally offered with the Mag Agenda Executive would after be fabricated accessible for the Model 50 cyberbanking typewriter, which accurate proportional agreement with 96-character elements.

IBM additionally awash a band clairvoyant that could be affiliated to 360 alternation mainframes, and would apprehend the MT/ST tapes. Thus a certificate typed on an MT/ST Selectric could additionally be entered into a mainframe abstracts file.

Selectric Composer

In 1966, IBM appear the Selectric Composer. This awful adapted Selectric produced camera-ready justified archetype application proportional fonts in a array of chantry styles from 8pt to 14pt.5 Actual able on a appropriately adapted apparatus by a accomplished abettor and printed assimilate baryta (barium sulfate-coated) cardboard "would booty an able to acquaint ...was not the artefact of a Linotype or Monotype machine".6

Characters were proportionally spaced, actuality from 3 to 9 units wide, with the admeasurement of a assemblage actuality selectable as either 1/72", 1/84", or 1/96", to acquiesce for altered sizes of type. Tab stops could alone be positioned at intervals of one-sixth of an inch, or one pica. To abutment backspacing over ahead typed characters, the agreement cipher for the aftermost 40 or so characters typed was mechanically stored by baby sliding plates in a carrier wheel.

Like the Varityper with which it competed, the aboriginal apparatus appropriate that actual be typed alert if the blazon was to be justified. The aboriginal time was to admeasurement the breadth of the band and calculation the spaces, recording abstracts apprehend from a appropriate punch on the appropriate margin. The additional time it was typed, the abettor set the abstracts into the punch to set absolution for anniversary line. The action was annoying and diffuse but provided a way to get camera-ready, proportionally spaced, justified archetype from a desk-sized machine