<
hardware> (Obsolete, or "bit-shift keyboard") A non-standard
keyboard layout that seems to have originated with the
Teletype ASR-33 and remained common for several years on
early computer equipment. The ASR-33 was a mechanical device
(see
EOU), so the only way to generate the character codes
from keystrokes was by some physical linkage. The design of
the ASR-33 assigned each character key a basic pattern that
could be modified by flipping bits if the SHIFT or the CTRL
key was pressed. In order to avoid making the thing more of a
Rube Goldberg
kluge than it already was, the design had to
group characters that shared the same basic bit pattern on one
key.
Looking at the
ASCII chart, we find:
high low bits
bits 0000 0001 0010 0011 0100 0101 0110 0111 1000 1001
010 ! " # $ % & ' ( )
011 0 1 2 3 4 5 6 7 8 9
This is why the characters !"#$%&'() appear where they do on a
Teletype (thankfully, they didn't use shift-0 for space).
This was *not* the weirdest variant of the
QWERTY layout
widely seen, by the way; that prize should probably go to one
of several (differing) arrangements on
IBM's even clunkier
026 and 029 card punches.
When electronic
terminals became popular, in the early
1970s, there was no agreement in the industry over how the
keyboards should be laid out. Some vendors opted to emulate
the Teletype keyboard, while others used the flexibility of
electronic circuitry to make their product look like an office
typewriter. These alternatives became known as "bit-
paired"
and "typewriter-
paired" keyboards. To a hacker, the
bit-
paired keyboard seemed far more logical - and because most
hackers in those days had never learned to touch-type, there
was little pressure from the pioneering users to adapt
keyboards to the typewriter standard.
The doom of the bit-
paired keyboard was the large-scale
introduction of the computer terminal into the normal office
environment, where out-and-out technophobes were expected to
use the equipment. The "typewriter-
paired" standard became
universal, "bit-
paired" hardware was quickly junked or
relegated to dusty corners, and both terms passed into disuse.
[
Jargon File]
(1995-02-20)