BASIC
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Why would a keyboard have a dollar sign but not a multiplication sign? Even though interactive processing (as opposed to batch processing with punched cards) was a novelty, teletypewriters had been used as interfaces to computers long before the 1960s. Various sorts of TTYs, teleprinters, or "printing telegraphs" were used commercially as a means of textual communication beginning in the 1910s. Based on pre-ASCII characters codes that came from telegraphy, these systems were used to transmit dollar amounts much more frequently than they were used for sending mathematical equations. Murray Code, the 1901 revision of the standard 1870 telegraph code, included two characters that allowed "shifting" into alternate sets. A shifted "D" would become a "$" in Murray Code. | Why would a keyboard have a dollar sign but not a multiplication sign? Even though interactive processing (as opposed to batch processing with punched cards) was a novelty, teletypewriters had been used as interfaces to computers long before the 1960s. Various sorts of TTYs, teleprinters, or "printing telegraphs" were used commercially as a means of textual communication beginning in the 1910s. Based on pre-ASCII characters codes that came from telegraphy, these systems were used to transmit dollar amounts much more frequently than they were used for sending mathematical equations. Murray Code, the 1901 revision of the standard 1870 telegraph code, included two characters that allowed "shifting" into alternate sets. A shifted "D" would become a "$" in Murray Code. | ||
| − | Interestingly, the original, North American Commodore 64 keyboard sported a pound sterling sign (£), a figure absent from other U.S. computers of the time. The presence of this key is a clear indicator of Commodore's plans to sell its computers in the United Kingdom, although the key had a precedent in Murray Code, which also features a pound sterling sign. | + | Interestingly, the original, North American Commodore 64 keyboard sported a pound sterling sign (£), a figure absent from other US computers of the time. The presence of this key points to Commodore's plans to sell its computers in the United Kingdom, although the key had a precedent in Murray Code, which also features a pound sterling sign. |
| − | The dollar sign is still used in some of today's workhorse programming languages, such as Perl and PHP. In both of these, it is used to indicate a variable by being placed at the beginning, rather than the end, of the variable name. In Perl it specifically indicates a ''scalar'' variable, since $ looks like S for scalar. | + | The dollar sign is still used in some of today's workhorse programming languages, such as Perl and PHP. In both of these, it is used to indicate a variable by being placed at the beginning, rather than the end, of the variable name. In Perl it specifically indicates a ''scalar'' variable, since $ looks like S for "scalar." |
== Altair BASIC and Micro-Soft == | == Altair BASIC and Micro-Soft == | ||
