From Newsgroup: comp.sys.ibm.ps2.hardware
https://knowbility.org/blog/2023/accessibility-apis-part-2
" When Screen Readers Got GUI
Screen readers have never literally read the screen, of course. Only
something on your side of the thirteen-inch amber CRT monitor could do
that. However, as the earliest screen readers emerged during the
mid-1980s, such as Textalker for the Apple II and Jim Thatcher's
in-house IBM screen reader, they did read video memory, which consisted
of a couple of easily-accessed kilobytes of values representing text characters (i.e., the ASCII standard), plus additional memory addresses
that stored color values, once that became a thing. A twelve-year-old
could read and write to it: I was, and I did during the early '80s.
Screen readers' tasks all revolved around this simple UI. They echoed
typed text, automatically read lines scrolling up from the bottom, automatically announced text with a specific background color that
designated a selected menu item, provided a special review mode and
review cursor that could explore the entire screen, sent their output
text string to a hardware speech synthesizer, and granted the user
control over all of it through more buttons and switches than a NASA
manned space vehicle. When a program switched into "graphics mode" in
order to draw the screen as a "bitmap" pixel by pixel, screen readers
clammed up."
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