🚀 go-pugleaf

walls@saifr00.cfsat.honeywell.com (Gerald Walls) writes:

> dchivers@engr.UVic.CA writes:
>>merchant@cbnews.cb.att.com (shahrukh.s.merchant) writes:

>>> [Typing ^P causes screen output to echo to the printer]

>>>My questions:  What is ^P supposed to do?  Where is it documented?
>>>Why doesn't it abort?  How can I disable this function?  How can I
>>>turn it back on, should I decide that I do want to use it occasionally?

>>Apparently, ^P toggles a print capture state.  If you are connected to a
>>printer, everything typed will be echoed to the printer until ^P is hit
>>again. I can't find any documentation for this in any DOS references
>>that I've looked at. I'm not sure how to disable it but a second ^P
>>will end it.

>I don't think it's a DOS functions.  I believe it is built into
>the BIOS.

Once it may have been in BIOS but no more.  If I can find it I'll look at
the BIOS source for the original 1981 PC to check on this.

Originally the echo-to-printer function was toggled by CTRL-PrtSc, but
that seems to have disappeared sometime in the distant past.

A quick look at the source code for the IBM PC/AT BIOS reveals that if you
hit CTRL-PrtSc it is recognized as a special case, causing the keyboard
interrupt handler (int 0x09) to place code 0x0072 in the keyboard buffer.
(Note that this key combination is defined only for an 88-key keyboard;
the "enhanced" keyboards put PrtSc on a special-purpose key which sends
the 0xE0 prefix.)  Testing a few systems in the area I found that CTRL-PrtSc
has no effect any more.

A previous poster suggested that if you accidentally hit ^P and keep getting
ABORT/RETRY? messages, just hit ^P again and the next response of "A" to
abort will return you to your normal programming.  This technique works,
at least for the systems I tested.

Joe Morris