Re: IBM, sonic delay lines, and the history of the 80x24 display

Ben Collver <bencollver@tilde.pink> writes:

Some theories about the 80x24 and 80x25 sizes
=============================================
Arguments about terminal sizes go back decades, [5] but the article
80x25 presented a detailed and interesting theory. To summarize, it
argued that the 80x25 display was used because it was compatible with
IBM's 80-column punch cards, [1] fits nicely on a TV screen with a
4:3 aspect ratio, and just fit into 2K of RAM. This led to the 80x25
size on terminals such as the DEC VT100 terminal (1978). The VT100's
massive popularity led to it becoming a standard, leading to the
ubiquity of 80x25 terminals. At least that's the theory.

It's always be obvious to me that the PC was 80x25 so that it could
accurately emulate a 3270 24 line display.

A 3270 HAS a 25th line where is displays some additional information
like whether the keyboard is locked.  There were 24 lines of data and a
25th line for status information.

--
Dan Espen