Tikalon Blog by Dev Gualtieri

Tikalon Header

IBM Selectric Typewriter

August 3, 2011

I used many Selectric typewriters in my early career, and I even bought one while I was a post-doc . My first published papers were typed on Selectrics, and I used Selectric computer terminals, called IBM 2741 terminals , attached to IBM System/360 and System/370 series mainframe computers .

I personally typed my dissertation on a rented Selectric II. Since those were the days before word processing , the Selectric that I rented had a correcting feature that would mechanically "lift" letters from the page. The Selectric was introduced as an IBM product fifty years ago, on July 31, 1961, when I was a high school freshman.[1-3]

Figure caption

An IBM Selectric Typewriter

Photograph by Oliver Kurmis, via Via Wikimedia Commons.

The Selectric solved a physics problem that all typewriters , manual and electric, faced. You needed to accelerate a massive object (the type carrier) very quickly and have it impart a particular impulse to the ink ribbon to transfer the typed character onto paper, often making several carbon copies . In all typewriters of that time, which were not that different from the 1874 Sholes-Remington typewriter , the type carriers were metal bars with the impact character on the end, and they needed to move quite a long distance between their resting state and impact.

The IBM engineering team scrapped the traditional typewriter concept by replacing the massive array of type bars with a far less massive ball. Said H. Wisner Miller, an IBM vice president during its Selectric era, "... We threw away everything but the alphabet."[3]

The ball contained the impact characters over most of its surface, and a particular character was selected by suitable rotation and tilting of the ball. All this movement required 2,800 parts.[3] One side benefit was that the ball could be swapped for one of an alternative typeface, such as mathematical symbols and foreign language characters.

Selectric typeball.

An IBM Selectric typeball (Prestige Elite), shown here as a composite of two Wikimedia Commons images, here and here.

I mentioned that Selectrics were used as computer terminals, also, so it wasn't much of a stretch to build a word processor around a Selectric. One very successful version of this was the Magnetic Card Selectric Typewriter . The data storage was on a magnetic analog of the venerable punch card , and the process was cumbersome, since the only I/O was through the typewriter.

A lot of paper was consumed in getting that perfect, final version of your typescript, but this word processing system was very popular. About 13 million Selectrics of all types were sold by 1986,[1] and at one time it held seventy-five percent of the US market.[2]

IBM missed an opportunity in computer terminals, since the Selectric didn't speak "ASCII ," and it had a limited character set of just the 44 typewriter characters and their upper case values. Bob Bemer, an IBM computer scientist who helped to define ASCII, argued in favor of ASCII compatibility, but his recommendation wasn't followed.[3] Computer people still used Selectrics as terminals for non-IBM computers. My IBM 2741 terminal spoke APL , compliments of the proper type ball.

Eventually, an even more elegant impact-printing mechanism, the daisy wheel , was developed. Daisy wheel printers were faster, and they had fewer mechanical parts, while the heavy Selectric followed in the "Big Iron " tradition of the IBM mainframes of its era. I had a Diablo 630 daisy wheel printer in my office for most of the 1980s, and this was driven by my WordStar word processor program running on a CP/M computer.

Daisy wheel type element

Daisy wheel type element.

(Via Wikimedia Commons).

Many authors, in the dim past before computer word processing, have used IBM Selectrics in their work. I've mentioned two of these, Hunter S. Thompson and Isaac Asimov , in my blog articles.

References: