When I read that I thought of "Stop A" on Sun workstations - and indeed that is mentioned on the wikipedia page:
http://en.wikipedia.org/wiki/Magic_SysRq_key
Mind you I don't think I ever used "Stop A" on a Sun for anything constructive...
http://en.wikipedia.org/wiki/Magic_SysRq_key
Mind you I don't think I ever used "Stop A" on a Sun for anything constructive...
Back at the dot-com I worked at, we used to have a SPARCstation 5 that we used for SPARC-II arch builds. It was a nice machine, but it had a dead NVRAM battery so it would lose its configuration every time we lost power in the building (which was a lot, because rolling blackouts used to be a thing in California).
Anyway, an interesting quirk about the SPARCstation machines is that the MAC address for the NIC is stored in NVRAM, and when you lose the NVRAM settings it defaults to ff:ff:ff:ff:ff:ff AKA the broadcast address. So by default, on boot, this machine would start sending out DHCP requests and other network traffic with a source address of the broadcast address. The switches we were using did not like that, and would start flooding all of their ports with traffic. The only way we found to fix it was to reboot the switches.
So, there is at least one constructive use for "Stop A": you can use it to configure a MAC address on your SS5 so that it doesn't inadvertently bring down the whole network in a massive broadcast storm.
>b -s
# ed /etc/passwd
Ahh, the good old days... I once implemented a nice little boot device selecting utility in for for some of my Suns. All written in Fourth, and executed by the firmware on every boot.