2010-09-10

PrtScn, SysRq, ScrLk keys

On Sep 10, 1:26 am, kodifik wrote:
> How can you dare to declare Ins, Del, SysReq keys defunct?
> I use them all the time in my Linux and -believe me- it's not a dead

i don't think i've declared Del defunct.

i have made similar remarks about Ins, SysReq keys defunct
though. I believe you are referring to this page

• 〈Computer Keyboards Gallery〉
http://xahlee.org/emacs/keyboards.html

Quote:
-------------------------------
Note the PrtScn (Print Screen) key, SysRq (System request) key, ScrLk (Scroll Lock), Break keys. These keys are historical relics and are more or less defunct today, except the Print Screen key that is often used for creating screenshots in Microsoft Windows.

Here's a summary of what these keys are, based on Wikipedia:

* PrtScn: In 1990s or earlier, it sends the screen's text into a serial port. Literally, causing the screen to be printed. (at the time, most monitors can only display text.) Today, this key is used in Windows and Linux to do screenshot (copy screen bitmap into the clipboard). This key is not used on the Mac.
* SysRq (System request): This key causes a interrupt to the operating system. It is kinda like the role of today's Control-Alt-Delete on Windows. However, this key is pretty much defunct today.
* ScrLk (Scroll Lock): Pretty much a defunct key today. Used to toggle the behavior of arrow keys so that, when ScrLk is on, the up/down arrows scrolls the window.
* The Pause and Break are 2 keys. They are pretty much defunct today. They were used for sending a interrupt signal of sorts, as today's more familiar 【Ctrl+c】 on PC and 【Cmd+.】 on Mac.
-------------------------------

Depending on how you want to define the meaning of “defunct”, it's common fact that these keys are not used much by vast majority of apps. Many PC keyboards don't even have these keys anymore. Apple keyboards don't have them.

i've also linked to Wikipedia on these keys so you can read about them.

Xah

1 comment:

  1. In GNU/Linux, the scroll lock is extremely useful during boot when lots of messages from the kernel and init comes on the screen and the only way to read it is to hit scroll lock or redirect output via serial port. For developers, this is a must have.

    Also, the system request key is used a lot.
    When X crashes, it allows to put the keyboard in raw mode, switch to a terminal and check why. It also comes with lots of other practical functionalities which enables kernel developers (and people looking for kernel bugs) really needs.

    I trash all keyboards which does not have these two extremely useful keys.

    Keys which I find totally useless and annoying are: windows key (but can be remapped to compose) and multimedia keys

    ReplyDelete