What makes a "Linux" keyboard different from a "Windows" keyboard?

[TuxKey]

Didn't know about the Amiga keyboard funny. One thing I don't understand is why different companies keep using a brand logo instead of putting their own logo there. If I was making a keyboard I would think of something creative to put there instead of a company logo that doesn't belong to me. If I didn't know any better I would think someone is getting paid hahaha.
Simply put stamping a windows logo there is lack of imagination in my humble opinion. What else would you call an unused opportunity to let your creativity flow


Sent from my iPhone using Tapatalk

[Menuhin]

A successful technical trolling post by zslane!

[zslane]

Actually, I am working on a project in which I need to understand how Windows users, Mac users, and Linux users prefer to arrange their bottom row modifiers (and why). Having used my share of Windows boxes and Macs over the decades, those two aren't a mystery to me. But I am not a heavy Linux user, and I have always gotten by just using conventional Windows keyboards with Linux boxes, so when I see folks say things like, "I use Linux a lot, so I like the so-and-so layout," I have no clear understanding of why they say that.

I had a vague awareness of the connection between the HHKB and the Sun Type 3 keyboard, but I am interested in learning how that relates to a modern, general purpose "Linux layout", as it were.

[infodroid]

What you might need to know about modern Linux users is that most of them have adapted to use the standard PC layout, and they like to remap keys.

Most Linux programs make use of Control and Alt, and so they are required. As for the Super (Windows) key, it is mainly reserved to control graphical desktop environments. Some people that don't care about GUI controls might remap Super to serve as a different modifier for use with special programs.

Also important to note is that for ergonomic reasons, a significant number will remap the 1.75u Caps Lock key and put it to better use, since it is prime real estate on the home row. In my experience with Linux users, people are split between mapping it either to Escape or to (left) Control. There is a minority that might replace it with the Super key, or remap it to a more exotic modifier like Meta or Hyper.

And what I have said is true of Linux users is also true for Mac users that might be called command line junkies.

I don't know any Linux users that speak of liking the "so-and-so" layout. If you can be more specific, then it might help. The only such layout that comes to mind is the HHKB. But I'm sure you're familiar with that now.

Are you sure they are not just talking about ergonomic keyboard layouts, like Dvorak or Colemak?

[Findecanor]

One was a solid A and the other was an outlined A, which meant that, for example, left-Amiga-Q was a different shortcut than right-Amiga-Q. What a wonderful idea, haha! I can just imagine the calls to tech support.

My brain wants to remember that both Amiga keys were for program shortcuts back in AmigaOS 1.3 but that the right left Amiga key changed in AmigaOS 2.0 to be used by the windowing system only .. but I might be wrong.
Well, at least both Alt keys were used for symbols - not divided into Alt and Alt Gr like on PC keyboards.

Edit: I checked my Amiga 500 User's Manual. Both keys were described as having the same functionality but the left Amiga key was called the "Commodore key" first with the note "Could also be an A".
Edit: I also checked my AmigaOS 3.0 Workbench manual. It was the Left key that was used by the windowing system.

Actually, I am working on a project in which I need to understand how Windows users, Mac users, and Linux users prefer to arrange their bottom row modifiers (and why).

The thing with Unix and Linux is that there is no body that produces any official "style guide" like Microsoft and Apple have done. Unix / Linux is very old and there have been a lot of different window managers and desktop environments (both open source and commercial) ... and then most of these have been very configurable.
So there are all sorts of ways that Unix / Linux users use the keyboard.

If I were you, I would base the bottom row on the MS Windows layout because most people these days use PC hardware anyway.
The Windows key ("Super" or "Meta" depending on what it is mapped to) is often used as a modifier either with other keys or with the mouse, for cycling between and manipulating windows and workspaces.
The major desktop environments GNOME 3.0 and KDE have such shortcuts. GNOME 3.0 also uses it to open a program launcher like on MS Windows.
I find the Menu key to be the least important - it is often omitted on PC keyboards these days anyway.

People using the Alt Gr key have muscle memory for it to be under the . key (period). That is where it is on full-size Windows keyboards, on compact Mac keyboards ... and BTW also on winkeyless G80-1800.

[zslane]

Okay, thanks everyone. You've been very helpful!

[citrojohn]

do you have any examples of linux keyboards? I've never heard of such a thing, unless you mean ones which have penguins instead of flags on mod4/super/winkey?

Cherry Cymotion Master XPress Linux:

I'm late to the party again, I fear - Seebart got in before me! But there is another Cherry "Linux" keyboard, the G83-6188. There seem to have been two types: one with a large penguin on the winapp keys, and another with a smaller penguin and "Linux" written above the lock lights. I presume the design changed when winkeys acquired a circular recess. I also suspect the difference from a conventional keyboard is entirely cosmetic - but this article may throw a little light on it.

[Zobeid Zuma]

Actually, I am working on a project in which I need to understand how Windows users, Mac users, and Linux users prefer to arrange their bottom row modifiers (and why). Having used my share of Windows boxes and Macs over the decades, those two aren't a mystery to me. But I am not a heavy Linux user...

One thing I like about Mac keyboards is that they have mostly remained symmetrical on the bottom row. I mean:

control option command space command option control

And when switching from Mac to Linux, I can simply swap control with command, and it's very easy. I do wish that more keyboards had all these bottom row modifiers the same size, so rearranging the keycaps would be trivial. I also would prefer not to have Fn on the bottom row where it breaks up the symmetry. I like the HHKB style with Fn on the right of right-shift -- not on the bottom row, but still close enough to "chord" naturally with the other modifiers.

[zslane]

I'd be curious to learn, from a statistical perspective, how many users actually use both right and left modifiers.

My touch-typing technique has evolved to the point where I don't use any of the right-side modifiers (I don't use R-Shift either), so in effect, they are just decorative and I don't really care what they are or how they are arranged. On my 60% boards, I only use the FN and PN keys (on the right side) for activating alternate layers or entering/exit programming mode. My left hand does all my chording.

(Personal history note: the dominance of my left hand for chording was entirely the result of heavy use of the Cntrl key for driving Emacs, and back then there was only one Cntrl key and it sat next to "A", and so my left pinky became the go-to finger for all chording, including all shifting.)

[infodroid]

I don't personally use any of the right hand modifier keys, including Shift.

However I note that ISO users will make heavy use of the right "Alt Gr". And many touch typists will make use of the right Shift, as that is a recommended technique.

And yet, I wonder about left-handed people... Whether they might prefer the right modifiers to the left ones.

[depletedvespene]

However I note that ISO users will make heavy use of the right "Alt Gr". And many touch typists will make use of the right Shift, as that is a recommended technique.

ISO user here. Indeed, the AltGr key sees a lot of usage. Some national layouts use the AltGr combinations for quite a lot of characters, and there are still plenty of available combinations that people (like me) use when making custom layouts with even more characters added to the original layouts.

I was a teenager at the time, but even back then, the introduction of this usage of AltGr struck me as a poorly tacked on design choice, as some AltGr combinations can be quite uncomfortable to type with the current setup. It would have been for the best to have three simmetrically laid out modifiers to each side of the space bar (say, Control Meta Alt SPACE Alt Meta Control), much like Apple did, and dedicate both Meta keys exclusively for the alternate layer of characters that is currently on AltGr, freeing what is really the "right Alt modifier".

If I had a time travel machine, perhaps I would schew killing Hitler, al-Wahab or Simon of Monfort in favor of fixing some design problems with the Model M physical layout (as well as altering some of the choices when the ASCII standard was made). Oh, well...

[seebart]

Hmm your a heavy "AltGr" user then depletedvespene which is pretty unusual but cool I guess. Yeah I use right and left modifiers all the time. I have to adapt when I don't have both like on my FC980C. In terms of ISO I'm gonna pull the old Apple trick and say this is my favorite ISO layout ever (which is true but wait for people to tell me it's not ISO) :

Spoiler:

M0115D_ISO_front.JPG (1.2 MiB) Viewed 6658 times

[Findecanor]

I was a teenager at the time, but even back then, the introduction of this usage of AltGr struck me as a poorly tacked on design choice, as some AltGr combinations can be quite uncomfortable to type with the current setup.

Mac and Amiga both use/d both Option/Alt keys for alternate symbols. I would suspect that NextStep did too.
It is MS-DOS/Windows that is the odd one here, for using the Alt key as another command key.

I don't know how different symbols were typed on languages other than English on the Model F that did not have an Alt Gr key.
The ones I have seen have had the English symbols as tertiary symbols or on the front.

I don't personally use any of the right hand modifier keys, including Shift.

I think I use the right Shift key only for the two keys immediately left of the ISO Return key.
I don't think I use the right Control key. To actually find out, I might need to actually pull it out, or to use a raw key logger.. if that even exists.

BTW. I do C-programming in Swedish layout with brackets and braces on the numeric row with Alt Gr. I am used to doing it that way.

[depletedvespene]

In terms of ISO I'm gonna pull the old Apple trick and say this is my favorite ISO layout ever (which is true but wait for people to tell me it's not ISO) :

When forcing the (ISO based) German language layout to an ANSI keyboard... the result is not THAT bad (disccounting the loss of <, > and | ... as long as they are assigned elsewhere), but other national layouts suffer DEARLY. The Spanish (Spain) layout gets the Ç key moved to the (US ANSI 1.5U) "\ " key, which is horrible, and the Spanish (Latin America) gets shit on in an even worse fashion, as the } and ] characters get moved there while the { and [ stay where they are. And it gets EVEN worse with big-ass Enter keys.

What's even worse is that where I live (Chile), few people actually care about making vendors follow the standard (*), so you can easily find keyboards with either ISO or ANSI physical layouts (big-ass are scarce nowadays, but used to be common, though), with either of the Spanish layouts, and sometimes even the US ANSI layout.

Worse yet, I have been unable so far to find if there IS a standard for a keyboard layout defined in the first place. I'm starting to think that there isn't and what most people think that is the "official definition" [Spanish (Latin America)"] is just a product of an IBM sales decision back in the late 80s.

I can rant about this for hours, I tell you...

[zslane]

Yeah, I'm strictly an ANSI user but even I find AltGr handy from time to time. I added the US International layout under Windows, and when I switch to it the R-Alt key effectively becomes AltGr. Morever, on my iPad, both Alt keys behave as AltGr by default.

[martink]

(which is true but wait for people to tell me it's not ISO) :

Okay, I'll byte

It's ISO alright, just as US ANSI is ISO https://en.wikipedia.org/wiki/ISO/IEC_9 ... rrangement

But when every keyboard layout is ISO, none will be.

[seebart]

(which is true but wait for people to tell me it's not ISO) :

Okay, I'll byte

It's ISO alright, just as US ANSI is ISO https://en.wikipedia.org/wiki/ISO/IEC_9 ... rrangement

But when every keyboard layout is ISO, none will be.

No, let's call it Apple ISO.

[Lustique]

I'd be curious to learn, from a statistical perspective, how many users actually use both right and left modifiers.[…]

I use all of the right modifiers, expect for right Ctrl, as I just found out. Since I use ISO-DE, I use AltGr a lot, RWIN is my compose key (LWIN is used for my WM), and the Menu key is almost never used, but I do use it from time to time, while I use RSHIFT a lot because of touch typing, although LSHIFT gets more use, I think. The right Ctrl is almost unusable to me when I try to reach it with my right pinky, and try to keep the rest of the fingers on the home row. Not only is my hand almost stretched to the max like this (small hands), I also have to twist my hand in a way that's it's little short of painful.

[…] (which is true but wait for people to tell me it's not ISO) :

Spoiler:

M0115D_ISO_front.JPG

I'm not gonna bite again, just so we can talk past each other once more.

[seebart]

I'm not gonna bite again, just so we can talk past each other once more.

Uh oh, that sounds almost a bit grumpy. I never said that AEK 1 layout was ISO, it's obviously not. I will say I like it better than normal German ISO which would be my default but since I'm a keyboard "nut" I use all kinds of layouts, actually mosty ANSI to be honest.

[Lustique]

No no, that's not the tone I was aiming for. I just got the impression that when you talk/write about ISO, you mean the legends, but when I talk/write about ISO, I mean the physical layout (independent of the legends), i.e. short left shift, ISO enter, no fugly pipe key, etc.

This just reminds me of some Chinese sellers who offer keycap sets like this or that and call it ‘ISO compatible’, although these sets lack both a short left shift and the key right next to it, making the additional ISO enter and 1u key completely useless. I don't even know why I care that much, because pretty much all sets like these that I can find at the moment are (IMO) really ugly.

Or maybe it's just my irrationally strong dislike of ANSI.

[zslane]

I don't want this to derail into a debate over ANSI-vs-ISO, but what is so dislikable about ANSI?

Suppose for a moment that there was a New ANSI, with AltGr in the R-Alt position (or configurable to L-Alt, or both, or neither), no Windows logos on the App/Super/Meta/whateveryoucallit key, and no MENU key. What then?

As an aside, ANSI may have a few flaws, but its Return key is not one of them. The ISO Return key needlessly consumes a good key position (right below Backspace).

[Lustique]

I don't want this to derail into a debate over ANSI-vs-ISO, but what is so dislikable about ANSI?

Suppose for a moment that there was a New ANSI, with AltGr in the R-Alt position (or configurable to L-Alt, or both, or neither), no Windows logos on the App/Super/Meta/whateveryoucallit key, and no MENU key. What then?

As an aside, ANSI may have a few flaws, but its Return key is not one of them. The ISO Return key needlessly consumes a good key position (right below Backspace).

To limit the derailment, I'll put my 2 cents in a spoiler

Spoiler:

For me, the dislike of ANSI mainly has two reasons:

• The layout has one less key, i.e. the key right next to an ISO left Shift
• The ‘pipe key’ (‘\|’) is just butt-ugly, in my opinion. Normal alpha-numeric keys, which includes ‘\|’, should not be anything else than 1u keys (IMO), unless we're talking about ergonomic layouts.

Furthermore, the ISO Enter key doesn't consume any key at all. What it does is it allows for one 1u key and takes up the awkward space that, in ANSI, is used by ‘\|’. I don't have a problem with the ANSI Enter key itself (although whenever I have to use an ANSI keyboard, I tend to miss the Enter key occasionally and hit ‘\|’ instead), but, as I already mentioned, I hate the awkward space it leaves above it.

I think something like splitting the Backspace key into two 1u keys, and putting Backspace where ‘\|’ is would make sense to me. You'd lose the fugly ‘\|’, have a ‘small Enter’, and have as many keys as ISO.
The following code for keyboard-layout-editor.com kind of illustrates what I mean:

Code: Select all

["Esc",{x:1},"F1","F2","F3","F4",{x:0.5},"F5","F6","F7","F8",{x:0.5},"F9","F10","F11","F12",{x:0.25},"PrtSc","Scroll Lock","Pause\nBreak"],
[{y:0.5},"~\n`","!\n1","@\n2","#\n3","$\n4","%\n5","^\n6","&\n7","*\n8","(\n9",")\n0","_\n-","+\n=","|\n\\",{a:7},"?",{x:0.25,a:4},"Insert","Home","PgUp",{x:0.25},"Num Lock","/","*","-"],
[{w:1.5},"Tab","Q","W","E","R","T","Y","U","I","O","P","{\n[","}\n]",{w:1.5},"Backspace",{x:0.25},"Delete","End","PgDn",{x:0.25},"7\nHome","8\n↑","9\nPgUp",{h:2},"+"],
[{w:1.75},"Caps Lock","A","S","D","F","G","H","J","K","L",":\n;","\"\n'",{w:2.25},"Enter",{x:3.5},"4\n←","5","6\n→"],
[{w:2.25},"Shift","Z","X","C","V","B","N","M","<\n,",">\n.","?\n/",{w:2.75},"Shift",{x:1.25},"↑",{x:1.25},"1\nEnd","2\n↓","3\nPgDn",{h:2},"Enter"],
[{w:1.25},"Ctrl",{w:1.25},"Win",{w:1.25},"Alt",{a:7,w:6.25},"",{a:4,w:1.25},"Alt",{w:1.25},"Win",{w:1.25},"Menu",{w:1.25},"Ctrl",{x:0.25},"←","↓","→",{x:0.25,w:2},"0\nIns",".\nDel"]

Maybe you could even split the right Shift key to make space for an Fn key, as with the HHKB layout (but that's beside the point):

Code: Select all

["Esc",{x:1},"F1","F2","F3","F4",{x:0.5},"F5","F6","F7","F8",{x:0.5},"F9","F10","F11","F12",{x:0.25},"PrtSc","Scroll Lock","Pause\nBreak"],
[{y:0.5},"~\n`","!\n1","@\n2","#\n3","$\n4","%\n5","^\n6","&\n7","*\n8","(\n9",")\n0","_\n-","+\n=","|\n\\",{a:7},"?",{x:0.25,a:4},"Insert","Home","PgUp",{x:0.25},"Num Lock","/","*","-"],
[{w:1.5},"Tab","Q","W","E","R","T","Y","U","I","O","P","{\n[","}\n]",{w:1.5},"Backspace",{x:0.25},"Delete","End","PgDn",{x:0.25},"7\nHome","8\n↑","9\nPgUp",{h:2},"+"],
[{w:1.75},"Caps Lock","A","S","D","F","G","H","J","K","L",":\n;","\"\n'",{w:2.25},"Enter",{x:3.5},"4\n←","5","6\n→"],
[{w:2.25},"Shift","Z","X","C","V","B","N","M","<\n,",">\n.","?\n/",{w:1.75},"Shift","Fn",{x:1.25},"↑",{x:1.25},"1\nEnd","2\n↓","3\nPgDn",{h:2},"Enter"],
[{w:1.25},"Ctrl",{w:1.25},"Win",{w:1.25},"Alt",{a:7,w:6.25},"",{a:4,w:1.25},"Alt",{w:1.25},"Win",{w:1.25},"Menu",{w:1.25},"Ctrl",{x:0.25},"←","↓","→",{x:0.25,w:2},"0\nIns",".\nDel"]

And another minor (and kind of duplicate) point: Should I ever be inclined to try out the Neo2 layout, I'd need the key right next to a short left Shift, because in Neo2, this key is a modifier key.

[depletedvespene]

My opinion? I prefer ISO over ANSI but use both.

- I like ISO Enter better, but that's a matter of taste.
- The extra key between the left Shift and the Z key is highly convenient; there truly is a shortage of keys for all the letters, numbers and symbols regularly used in whichever language you might prefer.
- Having a "regular" key 1.5U wide ("\ |" in the US ANSI layout) is not an elegant solution. Had that one become the standard backspace key and the extant one two regular 1U keys for "lesser" typographical symbols (like the Sun's "Unix" layouts and the HHKB later on that started this thread), this would not have been a issue. Yet... here we are.

That said, a smart key assignment layout laid over whichever physical layout you prefer is actually more important. A good point of comparison is how both (ISO) Spanish layouts ("Spanish (Spain)" and "Spanish (Latin America)") compare against each other... and the latter is hands down the best(*).


(*) The only bit where the "Spanish (Spain)" layout is better is that it does assign key combinations for Ç and · — for everything else, including and specially "ANSI degrading", the "Spanish (Latin America)" is best.

[enrique.aliaga]

Just my two cents: If you're a touch typist, the longer ANSI Enter key is much easier to reach with the pinky. That alone makes ANSI superior, IMHO.


Sent from my iPhone using Tapatalk

[DerpyDash_xAD]

I don't want this to derail into a debate over ANSI-vs-ISO, but what is so dislikable about ANSI?

Suppose for a moment that there was a New ANSI, with AltGr in the R-Alt position (or configurable to L-Alt, or both, or neither), no Windows logos on the App/Super/Meta/whateveryoucallit key, and no MENU key. What then?

As an aside, ANSI may have a few flaws, but its Return key is not one of them. The ISO Return key needlessly consumes a good key position (right below Backspace).

To limit the derailment, I'll put my 2 cents in a spoiler

Spoiler:

For me, the dislike of ANSI mainly has two reasons:

• The layout has one less key, i.e. the key right next to an ISO left Shift
• The ‘pipe key’ (‘\|’) is just butt-ugly, in my opinion. Normal alpha-numeric keys, which includes ‘\|’, should not be anything else than 1u keys (IMO), unless we're talking about ergonomic layouts.

Furthermore, the ISO Enter key doesn't consume any key at all. What it does is it allows for one 1u key and takes up the awkward space that, in ANSI, is used by ‘\|’. I don't have a problem with the ANSI Enter key itself (although whenever I have to use an ANSI keyboard, I tend to miss the Enter key occasionally and hit ‘\|’ instead), but, as I already mentioned, I hate the awkward space it leaves above it.

I think something like splitting the Backspace key into two 1u keys, and putting Backspace where ‘\|’ is would make sense to me. You'd lose the fugly ‘\|’, have a ‘small Enter’, and have as many keys as ISO.
The following code for keyboard-layout-editor.com kind of illustrates what I mean:

Code: Select all

["Esc",{x:1},"F1","F2","F3","F4",{x:0.5},"F5","F6","F7","F8",{x:0.5},"F9","F10","F11","F12",{x:0.25},"PrtSc","Scroll Lock","Pause\nBreak"],
[{y:0.5},"~\n`","!\n1","@\n2","#\n3","$\n4","%\n5","^\n6","&\n7","*\n8","(\n9",")\n0","_\n-","+\n=","|\n\\",{a:7},"?",{x:0.25,a:4},"Insert","Home","PgUp",{x:0.25},"Num Lock","/","*","-"],
[{w:1.5},"Tab","Q","W","E","R","T","Y","U","I","O","P","{\n[","}\n]",{w:1.5},"Backspace",{x:0.25},"Delete","End","PgDn",{x:0.25},"7\nHome","8\n↑","9\nPgUp",{h:2},"+"],
[{w:1.75},"Caps Lock","A","S","D","F","G","H","J","K","L",":\n;","\"\n'",{w:2.25},"Enter",{x:3.5},"4\n←","5","6\n→"],
[{w:2.25},"Shift","Z","X","C","V","B","N","M","<\n,",">\n.","?\n/",{w:2.75},"Shift",{x:1.25},"↑",{x:1.25},"1\nEnd","2\n↓","3\nPgDn",{h:2},"Enter"],
[{w:1.25},"Ctrl",{w:1.25},"Win",{w:1.25},"Alt",{a:7,w:6.25},"",{a:4,w:1.25},"Alt",{w:1.25},"Win",{w:1.25},"Menu",{w:1.25},"Ctrl",{x:0.25},"←","↓","→",{x:0.25,w:2},"0\nIns",".\nDel"]

Maybe you could even split the right Shift key to make space for an Fn key, as with the HHKB layout (but that's beside the point):

Code: Select all

["Esc",{x:1},"F1","F2","F3","F4",{x:0.5},"F5","F6","F7","F8",{x:0.5},"F9","F10","F11","F12",{x:0.25},"PrtSc","Scroll Lock","Pause\nBreak"],
[{y:0.5},"~\n`","!\n1","@\n2","#\n3","$\n4","%\n5","^\n6","&\n7","*\n8","(\n9",")\n0","_\n-","+\n=","|\n\\",{a:7},"?",{x:0.25,a:4},"Insert","Home","PgUp",{x:0.25},"Num Lock","/","*","-"],
[{w:1.5},"Tab","Q","W","E","R","T","Y","U","I","O","P","{\n[","}\n]",{w:1.5},"Backspace",{x:0.25},"Delete","End","PgDn",{x:0.25},"7\nHome","8\n↑","9\nPgUp",{h:2},"+"],
[{w:1.75},"Caps Lock","A","S","D","F","G","H","J","K","L",":\n;","\"\n'",{w:2.25},"Enter",{x:3.5},"4\n←","5","6\n→"],
[{w:2.25},"Shift","Z","X","C","V","B","N","M","<\n,",">\n.","?\n/",{w:1.75},"Shift","Fn",{x:1.25},"↑",{x:1.25},"1\nEnd","2\n↓","3\nPgDn",{h:2},"Enter"],
[{w:1.25},"Ctrl",{w:1.25},"Win",{w:1.25},"Alt",{a:7,w:6.25},"",{a:4,w:1.25},"Alt",{w:1.25},"Win",{w:1.25},"Menu",{w:1.25},"Ctrl",{x:0.25},"←","↓","→",{x:0.25,w:2},"0\nIns",".\nDel"]

And another minor (and kind of duplicate) point: Should I ever be inclined to try out the Neo2 layout, I'd need the key right next to a short left Shift, because in Neo2, this key is a modifier key.

welcome to the UNIX layout/Sun layout fan club my friend...

[Lustique]

It even has a physical Compose key… ( ͡↑ ͜ʖ ͡↑)

[DerpyDash_xAD]

It even has a physical Compose key… ( ͡↑ ͜ʖ ͡↑)

So.... Want to design a pcb/group buy/etc with me?

[Findecanor]

It even has a physical Compose key… ( ͡↑ ͜ʖ ͡↑)

All Sun Type 7 have a Compose key, whether they are in ANSI, ISO or Unix layout.

The USB HID "usage code" is the same as for the Menu key on PC keyboards.
But while the actual interpretation is host- or app-dependent, there is a explicit code for the LED indicator light code for "compose mode".
The Sun Type 5 has the light in the key. Sun Type 6 and Sun Type 7 have all LEDs above the keys, centred, with Compose being rightmost.

BTW, there are a few other keyboards with Cherry MX switches with a LED, on the bottom row/near bottom row but they use it for Caps Lock:
* KÛL ES-87 allows Caps Lock and left Control to be swapped and has keycaps for both configurations - with LED windows.
* Various vintage Cherry G80-series keyboards with a Model F XT - inspired layout that have it either under or to the right of the right Shift key.