From Barbara Waterhouse
by e-mail
The “useless” keyboard characters referred to in Feedback (7 December 1996)
do indeed have a use. If you are using your PC to connect to a mainframe
computer, pressing Sys Rq (or system request) asks the host application to send
a test request message.
As for the fallen-over L, which I agree does not seem to translate to a
character when using my PC as a PC, when I am using an emulator to connect to
the mainframe, it appears as shown on the keyboard, and is a very useful symbol
equivalent to the word “not” when programming in such languages as COBOL. I
would be most distressed if manufacturers were to suddenly start leaving it off
their keyboards.
