There is no question the Enhanced layout, released in 1986 with the IBM Model M keyboard, was very well designed and hugely influential, to the point that it's still the standard layout, with most alternatives created since then, be them full-size(-ish) or smaller, defined as variations of it (including the currently "official" Windows layout, which is simply the standard layout with three extra keys that few people actually wanted in the first place (YMMV)).
The Enhanced layout is, however, not perfect; its most glaring error is the overloading of the right Alt key as AltGr on "non-US" keyboards, breaking with this the design goal of having all the modifier keys present on both sides; it's safe to believe that whoever came up with that was probably thinking that it would be used for just a few symbols, an assumption that would have been quickly shown to be erroneous, even at that time, when studying some of the national layouts used in Europe (especially central Europe). On the other hand, it wasn't as obvious back then that a couple decades later, the Num Lock key would become a rather pointless relic (quite more so than other keys that unjustly get that flack, like Scroll Lock and Pause), because at the time it was still quite necessary to ease up the transition from the older XT and AT layouts.
There is one more gripe that I have with the Enhanced layout: the excessive area assigned to the right hand — not only the alpha block's right hand side is larger than the left one, the right hand is also expected to cover the the nav cluster and the numpad (not to say anything of the mouse). Even back in the late '80s I thought, while entering large amounts of data in spreadsheets, that it would be more comfortable to have the arrow keys on the left side, so I could move the cursor around with the left hand and type in the numbers with the right hand.
For the last few months I have been wondering, could the Enhanced layout have been done in a different fashion that addressed all these issues (including, of course, my pet peeves)? With the benefit of hindsight, decades of active usage, and my utter shamelessness, I fired up KLE and started fooling around with the layout, trying to come up with a new one that fulfilled these features/restrictions:
- It should be recognizable (to modern eyes) as a variation of the Enhanced layout.
- It should look like an extension of the preceding F AT layout, more so than the Enhanced layout.
- The navigation keys should be placed on the left side.
- Right Alt should be Alt, not AltGr, and a new modifier should be added to allow comfortable access to a third layer (and a fourth one) of extra letters and symbols.
- It should look like it was made by IBM (among other things, this means that key blocks should be rectangular, with no offset columns on the sides).
Rumors abound that IBM is working a new line of keyboards with a redesigned layout, which will supersede the current AT keyboards; not many details are available, but it seems that these new units will have dedicated arrow keys and two more function keys, for more per-program action goodness! (yes, in the early advertising for the Enhanced layout, a big point was made of the inclusion of these new-fangled F11 and F12 keys)
Let us keep imagining: in this alternate timeline, as the main engineer in charge of designing the Enhanced layout tinkers with the positioning of all keys, his wife, a heavy spreadsheet user, talks him into moving the navigation keys to the left side, to ease up her working in Lotus 1-2-3. His sister-in-law, a professional typesetter, happens to see a draft layout and goes nuts when she hears that only "a few extra symbols" would be added onto the extra layer. Dashes, pilcrow, paragraph, diacritics, extra letters in languages other than English?! Where would those go? One is pretty persuasive when presenting her case; the other one doesn't quite convince him at first, but his doubts are abated when he realizes that all the cool kids at the office don't use plain ASCII, but instead use code page 437 (not to say anything about code page 850 being "big" in Western Europe): a keyboard that only supports ASCII, as even the F AT keyboard does, is condemned to obsolescence.
The engineer refines draft after draft, taking inspiration from DEC keyboards (more so than in our own timeline) and overcoming the technical limitations a fourth modifier implies; to ensure the main alpha block will remain a rectangle, as IBM likes, he makes the radical decision of chopping off 0.25U on the right side of the alpha block, and uses it on the left side, easing up the allotment of keys over there. Once he is done, this is the layout he has produced:
Indeed, it looks like someone took an F AT, modified somewhat the alpha block, then moved up the F keys (and Esc) and added a bunch of new keys where the F columns were.
Let's go over the main features of note in the alpha block:
- On the right side, Backspace has been shortened to 1.75U, the \| key to 1.25U and the (horizontal, "ANSI") Enter to 2U.
- The modifier keys (Shift, Control and Alt) are present on both sides, and all of them are 1.5U in size.
- Both Shift keys are accompanied on their respective outer sides by a 1U Graph key. Those two new modifier keys take on the function of that "AltGr" thing from an early draft, allowing easy, comfortable usage of a third layer for extra symbols and letters (and a fourth one along with Shift, so those extra letters will have their lower and upper case forms!).
- On the top left corner, a dedicated 1.25U Delete key makes a counterpart to the Backspace key on the right side.
- To accomodate the above, the `~ key has been eliminated — not that it's needed, as the backquote ('`') and tilde ('~') characters will be readily available in the Graph layer.
- Tab has increased to 1.75U.
- Caps Lock has been reduced to 1U, and the Insert key, also 1U, has been placed to its left. With this, the Insert key is readily accessible but relatively "out of the way" of navigation keys.
- DEC's inverted T arrow cluster has been copied wholesale, albeit not fully raised by 1U, as in DEC keyboards. Instead, there is a small space between it and the non-inverted T HUDE cluster; this slightly complex shape will allow the left hand fingers easily find their way without the user looking.
- On the supranav row, Pause is now on the left side, so it remains a "corner" key, and away from Esc, to avoid accidental presses.
The reduced width of the Enter key isn't much of a problem, as long as the numpad remains separated by 0.5U, as the standard calls for. Even BAE (or NSBAE, in this case) can be done with little pain (because, again, the characters from the disappearing \| key can be taken in by the Graph layer).
Let us also take note of the numpad: it's pretty much the same as always, with two exceptions: the Num Lock key is tucked away with Scroll Lock (as was done later on in the IBM SSK); in its place, an equals sign is added, something spreadsheet users of the time would have definitely approved of. Also, somewhat more controversially, a comma key has been added, because lists of numbers, even in the good ol' USA, are separated by commas.
This is all well and good, but... what about difficulties in this layout?
When (our) Enhanced layout came out, the repositioning of the Control key was resisted, to the point that not few people to this day prefer to swap the left Ctrl and the Caps Lock keys. In this layout, doing that would mean either getting a measly 1U Control key above Shift, OR replacing both Insert and Caps Lock with a single 2U Control key (something perfectly doable, given what we all know about the IBM Model M keyboard) and then moving those to where left Control and right Control are, like this:
Do bear in mind that at this point in time, the Insert was widely used, so getting rid of it was not an option — besides alternating between insertion and overstriking text editing modes, it was also used to copy and paste text with Ctrl-Ins and Shift-Ins, a usage that would be codified in 1987 in the Common User Access (CUA) standard.
So, what to put under the Graph layer(s)? Oh, plenty! Thinking exclusively in terms of the code page 437, there's 127 caracters that could have been added:
One possible extension to the US national layout could have been this:
Note that in this thought experiment, I've limited myself to what I think IBM at the time could/would have done. Had it been for me, I'd have added a sixth row to the numpad (with keys for '(', ')', '^' and the letter E), but this escapes the purpose of the exercise. Same goes for splitting the space bar, another later development (in this case, and with this layout, I would have split the 7u space bar with three keys, 3U, 3U and 1U, as seen from left to right).
What do you think? What would you, with the benefit of hindsight, have done differently on the Enhanced layout, as it was released in 1986?