Upper case
Posted: Mon Sep 11, 2006 5:45 am
The workhorse printing device of the 1960s/early 70s, the 10 character-per-second Model 33 Teletype (trademark of the Teletype Corporation of Skokie, IL), printed only uppercase. If you sent it an ASCII character code for a lowercase letter, it simply printed the corresponding uppercase character. It printed on 8.5" wide rolled paper, usually "canary yellow."
In the minicomputer world, file name extensions were 3 characters long (uppercase of course), since we figured out a way to cram 3 characters into one 16-bit word (2 bytes) by limiting the character set to A-Z, 0-9, $, -, and underscore. The 3-character convention lives on to this day.
Lower case became popular in the mid-1970s with the invention of the 5x7 dot-matrix printer and, later, the daisy-wheel printer.
In the minicomputer world, file name extensions were 3 characters long (uppercase of course), since we figured out a way to cram 3 characters into one 16-bit word (2 bytes) by limiting the character set to A-Z, 0-9, $, -, and underscore. The 3-character convention lives on to this day.
Lower case became popular in the mid-1970s with the invention of the 5x7 dot-matrix printer and, later, the daisy-wheel printer.