Sun Microsystems keyboard is one of the worst. The following shows the one that is the keyboard for Sun's Ultra 5 computer (circa 2000).
This keyboard i used around 2000. (photo taken during that time) The key feel is mushy, using rubber dome switch. 〔☛ Guide to Computer Keyboard Key Switch Mechanisms〕
Some interesting aspects:
I hardly ever use this keyboard or sit in front of this computer. So i don't know what these keys actually do. Not sure the Copy, Paste, etc keys actually work out of box in Solaris. I don't think most of these special keys do anything useful by default. The desktop on unixes at the time (CDE) is quite unusable.
Most of the time, i just telnet/ssh from the PC running Windows NT, using a generic cheap PC keyboard. This Ultra5 is used as a server, it is one of the test bed for releasing our ecommerce software.
The key marked with a diamond ◆ is the Meta key, a key inherited from Lisp Machine's keyboards and today mostly known for its use in Emacs. This key is called Super in Linux today, but is referred to as Meta in Sun's documentation. This key is similar in purpose to the Command key ⌘ Cmd on Apple computer's keyboards, or the Windows key ❖ Win on PC keyboards.
Note the Compose key and Alt Graph keys. I've never used them. In writing this page, i learned that they are used to input special characters such as é ä ç ¿ £ ¥ ©.
The ⎄ Compose key is a key sequence lead key. Press compose (then release), then press 2 other keys will produce a symbol that's their combination. For example 【Compose ~ n】 creates ñ.
The AltGr key acts as a modifier. You need to hold it, then press another key to insert a symbol.
The ⎄ Compose key is thus much more convenient and powerful. It's convenient because you don't need hold it down. It's more powerful because following key sequences can produce much more possible combinations.
⎄ Compose key has a Unicode symbol ⎄. 〔☛ Unicode: Keyboard Symbols ⌘ ⏎ ↹ ⌫ ❖ ⇞ ⇟〕
The sound key and screen brightness keys seem funny to me, because i'm not sure these keys work out of the box on a typical unix workstation in the 1990s. Not sure if these machines typically have sound capabilities at all (⁖ a sound card).