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BLANKS.DOC
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1989-04-26
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17KB
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363 lines
-------------------------------------------
For personal, non-commercial use only
All rights reserved - May not be sold
-------------------------------------------
Copyright (C) 1988, 1989 by FM de Monasterio
BLANKs version 1.6b
--------------------
BLANKs is an MS-DOS/PC-DOS based, resident program that blanks the
screen after a preselected interval in the absence of a keypress. This
interval can be selected from 1 to 60 minutes. A selection higher than
60 minutes is set to 60. Selecting 0 minutes disables screen blanking;
blanking can be enabled by re-invoking with an interval of 1 to 60 min.
BLANKs is a terminate-and-stay resident (TSR) program. When installed,
the program uses less than 1000 bytes. It can be invoked repeatedly to
change its settings without producing multiple copies to memory. BLANKs
intercepts interrupts 8, 9 and 13h (and optionally 10h and 33h), and is
a "well behaved" TSR intended to run under MS-DOS or PC-DOS version 2.0
or higher.
----------------
OPERATION:
Screen blanking is obtained by direct commands to the hardware (video
controller) to turn off/on the video signal. This is a fast method that
operates successfully in the IBM PC/XT, PC/AT and in some IBM compatible
computers installed with MDA, CGA, EGA, VGA, and Hercules video adapters
or with IBM compatible adapters from other manufacturers.
NOTICE In some nonIBM microcomputers the program may not work and it
------ should NOT be used with other video adapter types unless they
are compatible with the IBM adapter at the register level (as
it is possible that some of these adapters might be damaged).
BLANKs intercepts interrupts 8h (hardware timer), 9h (keyboard), 10h
(BIOS video services), 13h (BIOS disk services) and 33h (mouse services
for device drivers following the Microsoft/Logitech Mouse format).
BLANKs will fail to operate if access to interrupts 8 and 9 is denied by
another program or resident loaded after BLANKs. This might occur with a
few communication and some (older) word processing programs.
- Interrupt 8 is called 18.2 times/s to update the computer time-of-the-day
counter (which is stored in the BIOS data area). Since a timer interrupt
can thus only operate within a period of about 55 ms or less (*including*
the overhead of DOS and other programs hooking on the timer), the program
uses direct commands to the hardware, written in assembly language, which
are issued, when needed, after the original timer interrupt is served.
- Interrupt 9 is called when a key on the keyboard is pressed or released.
When the hotkey service is enabled (see switch /H below), BLANKs triggers
blanking of the screen when the default hotkey combination (CTRL-B in non
shareware versions) is pressed. The hotkey code is then removed from the
keyboard buffer. Other keys are passed along for keyboard processing and,
if blanking had occurred, the screen is restored.
- Interrupt 10h is called to mediate a variety of video BIOS services. Since
these services are comparatively slow, many programs make direct writes to
the screen (which are not detected by the resident part of BLANKs) instead
of using BIOS video calls.
- Interrupt 13h is used to mediate a variety of hard disk and diskette BIOS
services.
- Interrupt 33h (which is not used by DOS or the BIOS) is used in Microsoft
and Logitech implementation of calls to the Mouse driver. This interrupt
is claimed by the driver during its initialization.
NOTICE To be able to monitor interrupt 33h, BLANKs must be installed
------ *after* the mouse device driver, as otherwise the driver will
not allow access to the interrupt. Also note that the driver
for a well known mouse can freeze the machine if interrupt 33
is found to be in use at the time of installation. This does
not occur with other drivers, e.g. Logitech's MOUSE.COM.
BYPASSING INTERRUPTS:
While installed, BLANKs bypasses the interrupt 8 when a blanking interval
of 0 minute has been selected (see below). Interrupt 9 is bypassed only
when both an interval of 0 minute and the switch /H- (see below) have been
selected. When /H- has been selected along with a nonzero interval, just
the hotkey service of interrupt 9 is bypassed. Hence, these two interrupt
activities of BLANKs are bypassed by the "0 /H-" selection; this may be of
use in case of testing potential conflicts with other programs.
Interrupts 10h and 33h are not intercepted when /K is selected; when this
switch is not selected, these two interrupts are intercepted but they are
not monitored unless switch /V is selected explicitly.
Note that during cloning of the program, the status of switch /K is *not*
copied as a default setting to the clone, as monitoring of video activity
would otherwise be impossible irrespective of the status of switch /V.
----------------
USAGE:
From the DOS command line or from a batch file, BLANKs is installed (or,
when already installed, modified) by the command:
BLANKs [?] [min] [/switches]
[?] Invokes a brief help and status display, identifying the type
of adapter for which the program is configured, the current
adapter, and program settings (if installed).
Pressing key <F1> displays further help on using the program.
If the program has not been installed, pressing <F2> displays
the default settings of BLANKs.
[min] Timed blanking interval in minutes. These are the minutes that
the program waits before blanking the screen in the absence of
keyboard activity. Valid selections are 0 or a number in the
range of 1 to 60. The selection of a 0-min interval disables
the timed blanking of the screen; the selection of an interval
larger than 60 defaults to 60 minutes for 2 digit inputs or to
the value (in the valid range) of the first 2 digits in inputs
containing larger numbers.
Null interval defaults to 3 minutes. This value may be changed
by cloning the program (see below).
Several switches are recognized. While shown as being preceded by a "/"
for the sake of clarity, the program accepts any character between space
( ) and slash (/) as a switch delimiter. Invalid switches abort loading
of the program. Switches are not case sensitive.
NOTE: Options marked with an asterisk (*) are available in the shareware
versions of BLANKs only.
/U Uninstall. Use only when BLANKs was the last resident to be
installed, as otherwise this would create a "hole" in memory.
The request is not honored if vectors to interrupts 8, 9 and
10h have been changed since installation. This can be caused
by a resident installed after BLANKs, or by a prior resident
that changes vectors set by programs installed after it. You
can determine if this is the case by using any of the memory
mapping programs that are available (search for interrupts 8
9 and 10; BLANKs.COM will be shown as an unnamed entry using
816 or 752 bytes, depending on the switch selection.)
/C Clone to disk the current version of BLANKs installed in the
memory.(*) This permits making the settings of this version
the default ones.
If the /C switch is entered in the command line alone,
default parameters do not become effective (unlike the
case of any other single switch specification) and the
resident parameters are copied to the cloned file.
If other switches or parameters are entered along with
/C, these new parameters and, when applicable, defaults
become effective, and are copied to the cloned file.
The clone file BLANKs.COM is written to the default drive and
directory. A warning is given if a file with the same name is
present there, and the user has the option to overwrite it or
to abort the cloning. Cloning will not overwrite files other
than those with a normal or archive attribute, or both.
/H Hotkey switch. In addition to timed screen blanking, BLANKs
allow for manual blanking of the screen by pressing a hotkey
combination. This combination is CTRL-B in the nonshareware
version of the program (see below). When BLANKs detects the
hotkey, it removes it from the keyboard buffer. However, be
aware that programs loaded after BLANKs may save this input;
this is the case, for instance, with some word processors in
which it is necessary to erase the hotkey character from the
text. In the shareware version, the hotkey combination can
be changed in case of assignment conflicts.
/H+ Enable hotkey operation. This is the default condition
when an argument is not specified for this switch.
/H- Disable hotkey operation. Can be reenabled with /H+.
/H? Allow the selection of a new hotkey combination (*) that
includes an alphanumeric key and one or more of the shift
shift keys: CTRL, ALT, left-SHIFT, and right-SHIFT. For
obvious reasons, CTRL or ALT, or both, must be included in
the hotkey combination.
/Ax Force configuration to specified adapter. This switch bypasses
the automatic configuration of the program for the video adapter
detected at the time of each calling. Valid specifications for
this switch are:
/Am configuration for the IBM Monochrome Display Adapter (MDA)
and Hercules graphics cards (HGA, HGA plus, and In Color);
uses and restores bit 3 of the video port 3B8h.
/Ac configuration for the IBM Color Graphics Adapter (CGA), the
Multi Color Graphics Array (MCGA) and compatibles; uses and
restores bits 0-3 of port 3D9h and bit 3 of port 3D8h.
/Ae configuration for the IBM Enhanced Graphics Adapter (EGA)
and compatibles; reads video ports 3BAh and 3DAh, and uses
and restores bit 5 of port 3C0h.
/Av configuration for the Video Graphics Array (VGA); uses port
3C4h, and uses and restores bit 5 of port 3C5h.
This configuration can be preserved as a default upon cloning of
(the shareware version of) BLANKs. Switch /A is useful if video
adapter type were incorrectly identified or an "unknown" result
were obtained (see the Help display called by option "?"). See
the above NOTICE on compatibility. ---
----------------------------------
/V Force monitoring of video activity mediated by BIOS and DOS calls
to interrupt 10h and by mouse calls to interrupt 33h. If enabled,
the switch avoids the timed blanking of the screen when the video
activity is detected; the switch, however, does not defeat manual
blanking of the screen, which can be unblanked only by keyboard
activity. Its function is negated by switch /K.
Note that the video output of some programs is not made through
these interrupts and, hence, such activity will not be detected.
Further, some mouse drivers can freeze the machine if interrupt
33h is found to be in use at the time of their initialization.
If you have such a driver and do not want to install it before
BLANKs, you then need to install BLANKs with the /K switch, or
uninstall BLANKs before installing the mouse device driver and
then reinstall it with the /V switch.
/K Force monitoring of keyboard activity only. When enabled at the
time of the (first) installation, this switch installs a shorter
resident component of less than 800 bytes that disregards video
activity via interrupt 10h and 33h. Because of the potential of
hanging the computer if a request to uninstall were made after a
change in the status of this switch, reinvocation of the program
ignores /K switch requests. Hence, to change the status of this
switch, BLANKs must be uninstalled and then reinstalled.
The status of the flag associated with the /K switch is ignored
during cloning, so that this switch cannot be set as a default.
/P Park the hard disk heads during manual or timed blanking of the
screen. All physical hard disks attached to the disk controller
that can be accessed via the BIOS are parked (uses highest disk
cylinder). Parking is suppressed if a BIOS disk(ette) service
is in progress at the time of blanking.
/P+ Enable hard disk parking. This is the default condition
when an argument is not specified for this switch.
/P- Disable disk parking. Can be reenabled with /P[+].
----------------
RELEASE:
The BLANKs utilities and the documentation (the "software")
are copyrighted by the author. In the present nonshareware
form, they are distributed free of charge for NONCOMMERCIAL
PERSONAL USE ONLY.
Although the nonshareware version of BLANKs lacks a few of
the features noted above, it is a completely usable program.
No support is for this version.
The shareware versions of the programs cost $7 plus mailing,
and can be ordered from the address below (360 kb diskette).
Indicate whether an 80286 or an 8086 version is applicable;
the 80286 version does not check for CGA "snow."
----------------
LICENSE and INJUNCTIONS
The copyright owner hereby licenses you, free of charge, to:
1. Use this software for noncommercial, personal purposes.
2. Make as many copies of the software as desired.
3. Distribute the software including via electronic means.
The copyright owner hereby specifically prohibits you from:
1. Charging or asking donations for copies of this software.
2. Distributing the software with commercial products without
a written permission from the owner.
3. Distributing the software via a for-profit organization,
either alone or with other software.
Any other use is prohibited without express, written permission in
advance from the copyright owner.
----------------
DISCLAIMER:
The author makes no warranty, either implied or expressed,
including, without limitation, any warranties with respect
to the software documented here, its quality, performance,
or fitness for any particular purpose. In no event shall
the author be liable for damage, whether direct, indirect,
special, incidental, or consequential, that arise from the
use of or any defect in the software. The entire risk as
to the quality and performance of the software is with the
user. By using this program, you acknowledge: (1) to have
read and understood all parts of the disclaimer and (2) to
have agreed with and accepted all of its provisions.
----------------
Refer all inquiries to: F.M. de Monasterio
7013 Barkwater Ct.
Bethesda, Md 20817
Messages may be left at: The DC Information Exchange BBS
202-433-6639
Sysop: Bill Walsh; 2400/1200 bps