From: utzoo!decvax!ucbvax!C70:info-cpm
Newsgroups: fa.info-cpm
Title: Re: CCP Bug in User #
Article-I.D.: ucb.1579
Posted: Thu Jul 22 20:25:06 1982
Received: Sun Jul 25 23:53:30 1982

>From fylstra.tsca@Sri-Unix Thu Jul 22 20:24:55 1982
An apparently little known fact about CP/M is that ANYtime a
program is doing console output through the BDOS, the user can
interrupt the program and return to the CCP by typing ^S^C.
The ^S pauses the printout, at which time the BDOS listens for
the resume character.  If the user types anything except a ^C,
the program will continue; otherwise, the BDOS will perform
a warm boot by jumping to location zero.  This means that the
BDOS and CCP will be reloaded and thus reinitialized in their
entirety.  The CCP, of course, performs its console output
by calling location 5, just like any applications program.

I am trying to remember where the BDOS stores the current User
number.  I recall that it is stored in location 4 along with
the current drive.  The question is whether a warm boot causes
the BDOS to initialize the User number, or your BIOS is zeroing
location 4 as part of its warm boot.

Dave Fylstra