Sholes and Glidden typewriter length. The redesigned platen also introduced the modern spacing functionality (horizontal and axial movement providing letter and line spacing, respectively). The cylindrical platen became "an indispensable part of every standard [typewriter]". By the end of 1872, the appearance and function of the typewriter had assumed the form that would become standard in the industry and remain largely unchanged for the next century. Although the machine possessed a cylindrical platen and what was essentially a QWERTY keyboard, two design elements that would later become essential were lacking: the ability to write in upper and lowercase letters and "visible" print. Although the
Not a typewriter replaced with the more general ioctl (I/O control) call, the "ENOTTY" error code was retained. "Typewriter" was what early Unix systems called a terminal. This usage goes all the way back to the First Edition of the Unix Programmer's Manual, dated November 3, 1971. For example, the description of the "hup" command was "hup hangs up the phone on the typewriter which uses it." The abbreviation TTY, which occurs widely even in modern UNIX systems, stood for "Teletype." The generic term "typewriter" was probably used because "Teletype" was a registered trademark of AT&T subsidiary Teletype Corporation and was too specific.