Commodore BASIC: Difference between revisions

Revision as of 00:18, 30 May 2010

Revision as of 14:50, 20 July 2010

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==Technical details==

<!-- Commented out because image was deleted: [[Image:C64scrn.png|right|frame|Commodore BASIC v2 running on a [[Commodore 64]]|{{deletable image-caption|1=Friday, 11 January 2008}}]] -->

A convenient feature of Commodore's [[read-only memory|ROM]]-resident BASIC [[interpreter (computer software)|interpreter]] and [[KERNAL]] was the [[full-screen editor]], which allowed users to enter direct commands or to input and edit program lines from anywhere on the screen&mdash;simply by pressing the <code>RETURN</code> key whenever the [[cursor (computers)|cursor]] happened to be on a line containing a valid BASIC statement. This marked a significant change in program entry interfaces compared to other common home computer BASICs at the time, which typically used [[line editor]]s, invoked by a separate <code>EDIT</code> command, a "copy cursor," [[Escape sequence]]s, or the like.

It also had the capability of saving named files to any device, including the [[Compact Cassette|cassette]] &ndash; initially a popular storage device in the days of the [[Commodore PET|PET]]. Most systems of the era only supported filenames on [[diskette]], which made saving multiple files on other devices more difficult, requiring the operator to note the recorder's counter display at the ___location of the file, which was inaccurate and prone to error. Most non-Commodore users worked around the problem by only recording one file per tape. With the PET, when the user requested to load a file by name from the cassette, the device would read data sequentially, ignoring any non-matching filenames until the named file was located and read into memory. The file system was also supported by a powerful [[storage record|record structure]] that could be loaded or saved to files. Another difference between the cassette transfer implementations of the Commodore and other systems was that Commodore tapes were encoded digitally, where other manufacturers usually used a less expensive analog interface which enabled the use of a standard tape recorder, but was much less reliable.