Ref: 16560003
Title: Print Screen Function
DATE: 8/15/89

Copyright 3Com Corporation, 1991.  All rights reserved.

In a 3+ network environment, you cannot use the print screen
function executed by the <SHIFT>+<PRTSC> key combination or the
PRTSC key itself (available on the IBM Enhanced Keyboard).  This
is the default condition.   The reason for this is to be fully
compatible with the IBM PC LAN program, which also disallows use
in a networking environment of the print screen function.  As a
result, the PRO.SYS driver takes over the interrupt 5 (that is,
<SHIFT>+<PRTSC>) vector and makes it a no-op.

However, you can reinstate the screen dump function for use with
a local printer (one attached directly to the workstation) or by
linking to a network printer (one attached to a server) by the
programs SAVEPRN.COM and SPRTSC.COM respectively.  These files
are available in the Ask3Com Forum, in the Public
Domain/Shareware Library.


SAVEPRN.COM

The 3+ program "RUNMINDS.COM" disables the <SHIFT>+<PRTSC>
feature by pointing the DOS interrupt vector for that feature to
a "do-nothing" routine.

Users with locally attached printers must use SAVEPRN.COM to re-
enable the print screen feature.

The program is run twice.  First, it saves the INT 5H (print
screen) interrupt vector contents into the INT 7Fh (unused)
interrupt vector.  Then, the program moves the contents of INT
7Fh to INT 5H.  Be careful to get the sequence correct.

Follow these steps to install SAVEPRN.COM:

1.  Copy the SAVEPRN.COM file to your boot disk.

2.  In the AUTOEXEC.BAT file, locate the line:

            RUNMINDS MINDSPRO MINDSBUF ...  MINDSDRV

3.  Insert the following line BEFORE the "RUNMINDS" line:

            SAVEPRN S

4.  Insert the following line AFTER the "RUNMINDS" line:

            SAVEPRN R


SPRTSC.COM

The SPRTSC program provides support for the Print Screen Function
on the IBM PC and compatibles.  It is intended to restore support
for this function in environments, such as networking, where it
has previously been unavailable.

SPRTSC is a Terminate-and-Stay-Resident (TSR) routine that is
less than 2 KB in size.  When SPRTSC is activated by the
<SHIFT>+<PRTSC> key sequence, it reads the current screen display
and writes it to a valid DOS filename or directly to the printer.

Follow these steps to install SPRTSC.COM:

1.  Copy the SPRTSC.COM file to your boot disk.

2.  Add a line containing "SPRTSC" to the bottom of the
    AUTOEXEC.BAT file.

For a 3+ PC user, SPRTSC may be added following the line
containing PRTSC.

Note:  Do not confuse SAVEPRN.COM or SPRTSC.COM with
PRTSC.EXE.  PRTSC.EXE is used for sending an end-of-file
(EOF) marker to the print spooler.  This is used primarily
for non-network applications for a print job to begin
spooling.  Either <CTRL>+<ALT>+<*> or <CTRL>+ALT>+<PRTSC>
(depending on the type of keyboard) flushes the job to the
printer device.


The default output for SPRTSC is the printer PRN or LPT1:.

A filename may be specified (in the AUTOEXEC.BAT file) when
SPRTSC is executed to redirect output to a DOS file; for example,
"SPRTSC c:\myscreen".  The "myscreen" file can then be sent to a
printer or edited in a document.

The SPRTSC "target file or device" must be accessible when the
<Shift>+<PrtSc> function is invoked.  When directing output to a
3+ printer, issue the command

              3P LINK PRN: \\servername\printername

before pressing <Shift>+<PrtSc>.

If there is an error when the Shift-Print-Screen function is
invoked, the workstation will sound a short beep.  This may
indicate that the DOS filename specified on the SPRTSC command
line is invalid or that the printer is not available.

One difference between the regular DOS Shift-Print-Screen
operation is that SPRTSC delays execution following the
<SHIFT>+<PRTSC> keys until it can call DOS to write the file.  If
your application is currently reading or writing a large file,
the delay may be several seconds.  For a remote PC, the delay may
be much longer.  If the PC issues an "Abort, Retry, or Ignore?"
message, SPRTSC will suspend execution until the message is
answered.
