Of course, there are many aspects to the architecture of a computer besides its instruction set. As an example of a user-interface element that varies from one computer to another, here is a laptop-esque keyboard in what I consider to be a very nice, if old style, color scheme:
The various keys are colored as follows:
These choices of color, besides making keys of different general types easy to distinguish, reflect various computer systems or terminals that I have happened to have the opportunity to use. The grey color of the printable character keys, in addition to reflecting many older terminals, also follows innumerable electric typewriters.
There is one alternative character set, sadly neglected on today's computers, that I would also wish to include on an ideal keyboard:
The illustration above shows how a particular ASCII keyboard arrangement, the typeweriter-pairing keyboard, to be described below, was used with the APL character set. (Of course, APL was originally used with IBM 2741 terminals; they used a typing element with 88 printable non-space characters; the extra characters added by Tektronix when they provided APL on their popular ASCII storage-tube graphics terminals are shown in dark green, as they became the standard.) Conventional ASCII characters, other than the letters and digits, which are on the same keys with APL, are shown in red on the left side of the key. In blue, on the lower right side of the key, are overstruck characters, shown as they were positioned on IBM 3270 terminals with an APL feature, allowing them to be entered with a third shift instead of by overstriking. (Underscore-del was also available, as the third shift of a key used normally for a control function.)
The Backspace and Enter keys are displaced by the arrangement of printable character keys shown; they return to their traditional 88-character electric typewriter positions with the arrangement found on the 101-key keyboard for the IBM Personal Computer. Unlike some others, as a touch-typist, I felt that IBM had finally gotten it right on their third try.
Keyboards used on ASCII terminals originally were designed so that the least significant bits of both characters on the key were the same; such terminals were called bit pairing keyboards. The positions of characters in ASCII were chosen so that this arrangement would have some resemblance to that of characters on a manual typewriter.
The original typewriter pairing keyboard layout for ASCII followed more closely the arrangement of characters on a typewriter, but in this case an electric typewriter. (It was because the quote marks, having a small area, should hit the paper with less force, that they were taken away from sharing keys with two digits, and were placed both on the same key in the electric typewriter.) The APL characters could be used with both a bit-pairing and a typewriter-pairing keyboard; the assignment would produce the same arrangement of APL characters if the underscore were the shift of the zero key. This did not often happen in practice, and was disparaged in the standards. One of the most notable uses of an APL terminal with the bit-pairing arrangement was an APL version of the Teletype Model 37, but at the time, many computers and terminals had bit-pairing keyboards.
Manual typewriter:
! " # $ % _ & ' ( ) * +
1 2 3 4 5 6 7 8 9 0 - =
¼
Q W E R T Y U I O P ½
: @
A S D F G H J K L ; ¢
?
Z X C V B N M , . /
Electric typewriter:
! @ # $ % ¢ & * ( ) _ +
1 2 3 4 5 6 7 8 9 0 - =
¼
Q W E R T Y U I O P ½
: "
A S D F G H J K L ; '
?
Z X C V B N M , . /
Uppercase bit-pairing ASCII:
! " # $ % & ' ( ) * =
1 2 3 4 5 6 7 8 9 0 : -
_ @
Q W E R T Y U I O P
[ \ +
A S D F G H J K L ;
^ ] < > ?
Z X C V B N M , . /
Upper- and lower- case bit-pairing ASCII:
! " # $ % & ' ( ) = ~ |
1 2 3 4 5 6 7 8 9 0 - ^ /
` {
Q W E R T Y U I O P @ [ _
+ * }
A S D F G H J K L ; : ]
< > ?
Z X C V B N M , . /
Typewriter-pairing ASCII (original form):
! @ # $ % ^ & * ( ) _ + ~
1 2 3 4 5 6 7 8 9 0 - = `
[ |
Q W E R T Y U I O P ] \
: " {
A S D F G H J K L ; ' }
< > ?
Z X C V B N M , . /
IBM 2741 terminal:
= < ; : % ' > * ( ) _ +
1 2 3 4 5 6 7 8 9 0 - &
¢
Q W E R T Y U I O P @
! "
A S D F G H J K L $ #
| ¬ ?
Z X C V B N M , . /
Keypunch
# , $ . 0
@ % * < - /
+ _ ) ¢ 082 | 1 2 3 &
Q W E R T Y U I O P
> : ; ¬ ' 4 5 6
A S D F G H J K L
? " = ! ( 7 8 9
Z X C V B N M , .
Keyboard for 5-level code (US version):
1 2 3 4 5 6 7 8 9 0
Q W E R T Y U I O P
- BEL $ ! & # ' ( )
A S D F G H J K L
" / : ; ? , .
Z X C V B N M
Three-bank manual typewriter keyboard:
1 2 3 4 5 6 7 8 9 0
Q W E R T Y U I O P
@ $ % ! _ * / - #
A S D F G H J K L
( ) ? ' " : ; &
Z X C V B N M , .
Note that the original version of the lower-case bit-pairing keyboard is also shown; many lower-case bit-pairing keyboards had the {[ and }] keys next to each other horizontally as on the modern modified typewriter-pairing arrangement on the IBM PC (and the DECwriter III and the VT 100), but the arrangement shown is the one that can be matched up to the APL keyboard image above.
What I am always hoping for in keyboards, besides a conventional arrangement, is convenience in entering characters additional to those of 7-bit ASCII.
Now this is a keyboard, and based on the manual typewriter, yet!
But the kind of keyboard I'm really looking for would look more like this:
Programming and mathematical symbols, reached by an alternate shift, are on the right side in blue; word processing characters are on the left side in red. Dark red indicates character substitutes, light red characters reached by an alternate shift.