Green letters on some IBM keyboards

[GreenAlt]

Dear keyboard experts,

since a long time I am the happy owner of an IBM Model M keyboard.  Some weeks ago I got me a Model M4 and noticed that there are strange similarities between the two:  The ALT keys of both keyboards are labeled with green letters.  (I did not pay attention to this fact before.)

My questions are:  What is the reason for the green lettering of the ALT keys?  Would the label "ALT" not be enough to distinguish this key from others?  Why the unique choice of color?

Many thanks in advance for your answers.

[ch_123]

Notice that SysRq (on the front side of Print Screen) is also green.

It's to indicate that holding down Alt and pressing the Print Screen button gives you SysRq.

[dissident]

yep mine are green too also the 'sysrq' under the 'print screen' button is green but that's it.  Manufacture date august 11 1988

[EverythingIBM]

And also, the secondary text on the numpad is a light brown colour.

[didjamatic]

Notice that SysRq (on the front side of Print Screen) is also green.

It's to indicate that holding down Alt and pressing the Print Screen button gives you SysRq.

Haha, I just learned something new!  Thanks CH!  I've worked on computers since before PC's and always thought that key meant "System Required" as-in, a compatible system is required to use Print Screen.  I was told this in the DOS days and never had a reason to doubt it.  Since I'm only a moderate Linux user, I've never used it for it's intended purpose, nor did I know about it.  I love it when I learn something new about something that has stared me in the face for nearly 30 years.

SysReq for those interested.

[GreenAlt]

Notice that SysRq (on the front side of Print Screen) is also green.

It's to indicate that holding down Alt and pressing the Print Screen button gives you SysRq.

Thanks for your answer, this makes perfect sense!

[EverythingIBM]

Haha, I just learned something new!  Thanks CH!  I've worked on computers since before PC's and always thought that key meant "System Required" as-in, a compatible system is required to use Print Screen.  I was told this in the DOS days and never had a reason to doubt it.  Since I'm only a moderate Linux user, I've never used it for it's intended purpose, nor did I know about it.  I love it when I learn something new about something that has stared me in the face for nearly 30 years.

SysReq for those interested.

IBM just left it sitting there on their layout for years to baffle home PC users. It's kind of ironic that lenovo is the first company to remove the system request key. How un-IBM of them, removing old terminal legacy garbage!

There's a lot of "Watson eggs" in IBM products, you just have to search for them.

[ch_123]

The functionality is still there, they just don't print it on the keycap.

It's useful/needed in certain operating systems. Such as Linux.

Of course, everything that IBM did that doesn't relate to Windows is garbage, hurr hurr hurr.