How System Requests Work and How to Add Your Own SysReq
How System Requests Work and How to Add Your Own SysReq
snee.la
How System Requests Work and How to Add Your Own SysReq
I needed to add a custom System Request (Sys Req or SysRq) to a linux kernel some time ago. While doing so, I dug deep into how it works and I thought I’d make a quick post about it. Here is a good SuperUser answer about what a SysRq is. You may also know about SysRq via REISUB. This post has three parts: how to raise a SysRq, how SysRq works (looking into kernel code), and how to add your own SysRq.
Disclaimer: This is my website.
Amazing. I've been 'staring' at the sys rq key for 20 years with Linux and many years before with Win/Dos, and never really knew how it worked, for what, or if it was still used for anything - even then.
Apparently (from light search) sysreq was mostly used in the old days to halt current job and enter a systems menu.
Anyway, thanks for fixing a long-standing knowledge gap :-)
I'm glad you appreciate it! It's always fun digging into kernel internals and learning new things :D
I'm also open to criticism about the writing if you have any.
No one knows what SysRq was meant for.