Chuck wrote
+=======================================================================
The alt-numeric keypad entry of "extended ASCII" (ALT+128 thru 255) is a
function of the IBM PC's keyboard BIOS and has been there since the very
first PC in 1981. Since it's a part of the BIOS it occurs below the
operating system, at least for DOS. Your actual mileage will vary since
later operating systems such as Windows and OS/2 (and I assume Linux)
will subvert the BIOS functions and introduce their own low level
keyboard support and their own mapping to graphic characters
================================================================
Chuck,
Actually I think the actual keystrokes were designed are adopted by ASCII long
before the
original PC. I remember using them in CP/M. However, not all font character
sets support
full or extended ASCII. So it is actually the font which must support the
character set.
Fonts on the PC were introduced in programs such as word processors and desktop
publishing
programs. Native BIOS and DOS did not support font sets. Most of the BIOS
functions I
remember controlled special characters like the function keys and scroll lock
and
print-screen ect. Fonts could only be supported by applications. With the
introduction of
Windows 1.01 there began some universal support for fonts on the PC. I'm sure
the keyboard
bios recognized that the special ASCII characters were there, but there just
was no way to
address the bios without a program. When Windows 3.0 came to be, it took
control of all of
the special characters and font control.
IBM was most influential in developing the standard 101 key keyboard. Even
Apple Computer
accepted it as a standard in it's MacII products in the late 1980's. Back in
the old days
each manufacturer had their own unique keyboard. Most were based on 88
characters. However
there was no standard. The 101 key keyboard became known as the "standard IBM
layout". Now
every computer uses it.
Phillip Franklin
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