Dec 152017
Tips on how to set up your DDCONFIG.SYS file for DoubleDOS.
File DDCONFIG.ZIP from The Programmer’s Corner in
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Tips on how to set up your DDCONFIG.SYS file for DoubleDOS.
File Name File Size Zip Size Zip Type
DDCONFIG.DOC 11136 4124 deflated

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Contents of the DDCONFIG.DOC file


The following material describes the various options which
may be specified to control various aspects of the DoubleDOS
multi-tasking software. These options are specified by entering
the appropriate values, each on a separate line, in a standard ascii
text file call DDCONFIG.SYS.

Many of these options provide an override for the appropriate
default, while others specify additional processing and monitoring for
which there is no default specified.

DoubleDOS Initialization Options
The following options control the ways in which DoubleDOS is
started, which keys are used to activate the various DoubleDOS
commands, and what additional processing or loading is to be initiated
by DoubleDOS upon startup.

Memory Partition Size
The memory partition size option allows the user to define a
value to be used automatically in partitioning RAM which remains after
DoubleDOS, PC-DOS, and any drivers or other resident software.This
value can be assigned automatically for either memory partition, with
the balance of available RAM going to the other partition.
Without some assignment being specified in DDCONFIG.SYS, DoubleDOS
will prompt each time at startup for the memory division information.

TOP SIZE = half ]
]} Either one can be "half" or numerals

Automatic Program Startup
DoubleDOS can automatically start a program or batch file execution
in either or both memory sections immediately upon startup. If desired,
multiple commands can be entered simply by specifying each command
separately. A maximum of 128 characters can be entered to be processed
automatically in this way.


DoubleDOS Menu Control Options
Certain features of DoubleDOS are accessed solely from a "menu",
or listing of commands. DoubleDOS permits the user some choices in the
presentation of the menu. The default is to use the "long" form of the
menu which contains detailed text describing option selections, as well
as certain system status information.

MENU = LONGdefault value; includes status
info and text explanations
MENU = SHORTsingle line format; no text
saves 9K of RAM
MENU = LINExxsame as above, but on line xx
instead of line 24

DoubleDOS Command Key Definitions
All of DoubleDOS' features are accessed using commands initiated
from the keyboard. Default values for each of these functions have been
chosen bearing in mind the objective of broadest possible compatibility
with applications software. However, it is impossible to consider all
applications which exist, as well as each new one in setting values for
these command keys.
Therefore, each DoubleDOS command key may be programmed by the
user. This permits the individual user to customize the command keys
both to suit personal preferences as well as to preclude conflicts with
application packages.
DoubleDOS commands are invoked by entering a two key sequence.
The first of these, the HOT key, is common to all of the other commands.
The second key of the sequence can be set individually for each command.
The first key must be selected from the following:

HOT KEY = ALT;default
HOT KEY = NUL;only the second key (from below) is needed
;to invoke the command. When using this
;option for single key operation, carefully
;inspect the values below, as they may conflict
;with standard values used by other software.

The second key may be any other key on the keyboard, and is
designated by the key's scan code (see table). These are specified

MENU KEY = xx;to invoke the DoubleDOS control menu
;default = 83 (DEL)
EXCHANGE KEY = xx;to exchange the two tasks on the screen (& kbd)
;default = 1 (ESC)
CANCEL KEY = xx ;to clear any contents of the DoubleDOS printer buffer
;default = 43 (\)
SUSPEND KEY = xx;to suspend the INVISIBLE section, or unsuspend
;default = 58 (Caps Lock)
CLEAR KEY = xx;to clear the contents of the keyboard buffer
;for the VISIBLE program
;default = 14 (BACKSPACE)

Specifying "0" for any of the values above disables that feature.

DoubleDOS I/O Control Options

Display Control Options
The display control options are used to provide initialization and
operational information to the DoubleDOS video control section. Options
may be combined with other display options to achieve the desired results.

DISPLAY = TEXT;reserves 4K for INVISIBLE display buffer, even on
;systems with graphics adapters. Graphics can not
;be made INVISIBLE and successfully recalled with
;this option.
DISPLAY = DEFAULT;brings up DoubleDOS on the display indicated by
;current MODE, and configures only for that display.
;same as if no DISPLAY statement is present. Saves
;4K when started on mono, or 16K when started on
;graphics, for INVISIBLE display.
DISPLAY = BOTH;reserves no buffer for INVISIBLE display. Requires
;that two display adapters are present on system.
DISPLAY = TWO;creates an INVISIBLE display buffer (based on the
;current mode) and permits the VISIBLE program to
;use both displays for itself.
;The DoubleDOS display options menu will not appear
;unless this option is used. Only use this option
;if you really have two displays (and adapters).
DISPLAY = 4-32K ;overrides size of INVISIBLE display buffer
;for display cards with higher density displays or
;multiple pages.
DISPLAY = MONO;sets 4K INVISIBLE buffer for screen address
;beginning at B000
DISPLAY = COLOR ;sets 16K INVISIBLE buffer for screen address
;beginning at B800
DISPLAY = FAST;eliminates DoubleDOS waiting for vertical retrace to
;display information. For use with display cards not
;requiring this extra delay to increase speed of;displays

Printer Control Options
The printer control options are used to provide initialization and
operational information to the DoubleDOS printer control section, which
includes the DoubleDOS printer buffer which is optionally provided for the
output to a parallel printer (LPT1).

The DoubleDOS printer buffer is available for use by a parallel
printer attached as LPT1, and can provide a buffer from 1K to 64K in size.
Since most printed output contains many spaces for formatting, the buffer
provides automatic space compression to increase its storage capacity.
The printer buffer, if used, may be driven either by hardware
interrupts (the faster method), or by the system's clock. The reason for this
distinction is that some printer adapters (AST, for example) do not support
interrupt driven printer output, and must use the clock in order to be able
to function.

The PRINT DRIVER statement in the DoubleDOS configuration file
provides the ability to alter the default, which is to install the
interrupt driven buffer. The PRINT BUFFER statement is used (if the
buffer is to be used) to specify an override for the size of the buffer.
The default is set to a 1K buffer.

PRINT DRIVER = BIOS;no printer buffer installed, use ROM BIOS
;printer interface
PRINT DRIVER = DIRECT;no printer buffer installed, but DoubleDOS
;printer interface used to "overlap" printing
PRINT DRIVER = INTERRUPT;default. printer buffer installed, and uses
;interrupt driven printing
PRINT DRIVER = CLOCK;printer buffer install, but uses system clock
;to initiate printing.useful for systems not
;supporting interrupt print or those which have
;other hardware which uses IRQ7.
PRINT BUFFER = 1-64k;default is 1K

DoubleDOS also permits the user to override the default port
addresses for printers on the system. The starting port address is
assigned for up to three parallel printers. This option is used on
non-IBM systems with different port addresses.

LPT1 = 3C0;can be any valid hex value for starting port address
LPT2 = xxx
LPT3 = xxx

Device Driver Loading
DoubleDOS provides the user with the ability to install separate or
different character device drivers for exclusive use by 1 memory section.
In addition, this feature is sometimes necessitated in order to resolve
conflicts between the driver and DoubleDOS, when the driver has already
installed when DoubleDOS is starting.

TOP DEVICE = drvr.sys;can be any valid device driver file name
DEVICE = drvr.sys;loads one copy of the driver after DoubleDOS
;for use by both top and bottom sections

Communications Control Options
The communications control options provide the ability to assign
the use of the system's communications resources exclusively to one of
the memory partitions.This would override the default, where both (RS-232)
COMM ports are available to either partition.


If only one comm program is to be run concurrently, it can be
run in either memory section with no special options. If more than
one comm programs will run concurrently, it is recommended that the
above options be used to prevent the two programs from interfering
with each other.
In addition, certain .BAS and .EXE programs reset the comm
ports whenever they are started or stopped. These options can also
be used to prevent this type of interference by preventing access from
the other memory section.
For some communications programs, particularly those running
at a high baud rate or without XON/XOFF protocol, it may be necessary
to adjust the system priority.See information elsewhere in this
document about the PRIORITY statement.

Miscellaneous Control Options

Time Share Priorities
The DoubleDOS user may alter the default values for processor
time allocation. The standard default is to favor the foreground (VISIBLE)
task by two to one over the background (INVISIBLE) task. Priorities may
be set to favor either task in the same (2-1) fashion, or to provide equal


Screen Saver Feature
The DoubleDOS user may specify that the display screen is to be
dimmed in order to save phosphor life after the specified number of
minutes have elapsed without keyboard activity. If the configuration
file option is not specified, this feature is not activated in DoubleDOS.

SCREENSAVE = x;time in minutes before dimming the screen. no default.

ous options which
may be specified to control various aspects of the DoubleDOS
multi-tasking software. These options are specified by entering
the appropriate values, each on a separate line, in a standard ascii
text file c

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