[Coco] Anyone ever tried that on a CoCo?

[Torsten Dittel]

"The OS-9 operating system has a file manager called "SCF" which handles
serial devices such as the console. One of the system calls available
will "stuff" the input buffer with a string which can later be recalled
by using the CTRL-A ("again") keyboard sequence. 
Microware programmers hid a credit string inside this buffer which you
can obtain by typing "CTRL-A" on a serial prompt that has never been
used (unless the program clears it). 
The easiest way to see this on most OS-9 systems is by pressing "CTRL-A"
at the LOGIN prompt. On some versions, pressing CTRL-A at the OS-9 shell
prompt when you first boot up will also produce it."