SYSINI.WRI from Windows 3.1

SUMMARY

The following information was taken from the Microsoft Windows operating system version 3.1 SYSINI.WRI file.

MORE INFORMATION

SYSTEM.INI File Settings

Windows initialization files contain information that defines your Windows environment. Windows and Windows applications can use the information stored in these files to configure themselves to meet your needs and preferences.

There are two standard Windows initialization files:

• WIN.INI, which primarily contains settings that Windows maintains to customize your Windows environment according to your preferences.
• SYSTEM.INI, which primarily contains settings that customize Windows to meet your system's hardware needs.

To order the Windows Resource Kit within the United States, dial:

   1-800-642-7676

Format of the SYSTEM.INI File

The SYSTEM.INI file contains several sections, each of which consists of a group of related settings. The sections and settings are listed in the SYSTEM.INI file in the following format:

   [section name]
   keyname=value

The keyname=value statement defines the value of each setting. A keyname is the name of a setting. It can consist of any combination of letters and digits in uppercase or lowercase, and it must be followed immediately by an equal sign (=). The value of the setting can be an integer, a Boolean value, a string, or a quoted string, depending on the setting. There are multiple settings in most sections.

You can include comments in initialization files. You must begin each line of a comment with a semicolon (;).

How to Read the Listings in This Document

In this document, settings in SYSTEM.INI are listed alphabetically within sections. However, the settings do not appear alphabetically in the SYSTEM.INI file. To change a setting, you need to search for it in the appropriate section.

The syntax, default value, and purpose appear in the following format.

SettingName=<value-type>

Default: The Windows default value for this setting. Purpose: A brief description of the function of the setting.

<value-type> indicates whether the value should be an integer, a letter, a range of numbers, a Boolean value, or something else. If you want to enable a Boolean setting, you can set the value to: True, Yes, On, or 1. If you want to disable the Boolean setting, you can set the value to: False, No, Off, or 0.

Changing Settings

When the Setup program creates the SYSTEM.INI file, it assigns default values to many of the settings. Other settings have values that correspond to the type of hardware you are using.

Some settings listed in this document do not normally appear in your SYSTEM.INI file. Most of these settings have a built-in default value that is present whether or not the setting appears in SYSTEM.INI. You might need to change one or more of these values to improve the performance of Windows or applications with your system.

To change the values of the settings described in this document, open the SYSTEM.INI file and edit it by using a text editor, such as Windows Notepad. Do not use a formatting editor, such as a word processor in document mode; it can corrupt your SYSTEM.INI file. For more information on how to use Notepad, see Chapter 12, "Additional Accessories," in the "Microsoft Windows User's Guide."

Any changes you make to SYSTEM.INI settings do not take effect until you restart Windows.

Caution: Do not change any settings that are not described in this document. If you need to change additional settings, refer to the Windows Resource Kit for the Microsoft Windows Operating System Version 3.1. Always back up your SYSTEM.INI file before you change any of its settings. That way, you can restore the original file if you make incorrect changes. Be careful when making changes to the SYSTEM.INI file. Your system will not work properly if you edit this file incorrectly.

[boot] Section Settings

All settings in this section, except for CachedFileHandles, are required. If you modify or delete one of these settings, Windows might not work properly. There are no specific default values for these settings; Setup assigns values based on your system configuration.

If you want to run a different application when you start Windows, change the following setting.

shell=<filename>

Default: None (Setup initializes this value as PROGMAN.EXE.)

Purpose: Specifies the Windows application that runs when you start

         Windows. Unless you change this setting, Program Manager will
         run when you start Windows. For example, if you want to run
         File Manager instead of Program Manager when you start
         Windows, you could change this setting as follows:

            shell=winfile.exe

[NonWindowsApp] Section Settings

The [NonWindowsApp] section contains settings that affect the performance of non-Windows applications.

The [NonWindowsApp] section can contain the following settings.

CommandEnvSize=<bytes>

Default: 0 for MS-DOS versions earlier than 3.2. Otherwise, the

         default is the value for the /e: option in the shell= command
         line in the CONFIG.SYS file.

         running batch files with the extension .BAT starts
         COMMAND.COM, so this setting also applies to batch files. The
         value for this setting must be either 0 or between 160 and
         32768. A value of 0 disables this setting. If the value is
         too small or too large, it will be rounded up to 160 or down
         to 32768. If the value is less than the current size of the
         actual environment, this setting will be disabled, as if it
         were set to 0. If you have specified the environment size in
         a PIF file for COMMAND.COM, the PIF-file setting overrides
         this setting.

Default: 0

Purpose: When this setting is disabled, the position and fonts used by

         a non-Windows application are saved in the DOSAPP.INI file
         when you quit the application. If this setting is enabled,
         the position and fonts used by a non-Windows application
         whose settings have not been previously saved in the
         DOSAPP.INI file will not be saved. If enabled, the setting
         can be overridden for each non-Windows application by
         selecting the Save Settings On Exit check box in the Font
         dialog box in the application.

Default: 1 on systems that use Windows version 3.1 grabbers. 0 on

         systems that use Windows version 3.0 grabbers.

         Windows application in a window on a system that uses version
         3.0 of the grabbers (usually 3.0 display drivers). Windows
         version 3.1 video grabbers (used in 3.1 display drivers)
         include built-in support for changing fonts when running a
         non-Windows application in a window. If you are using a 3.0
         grabber that has not been updated to include the ability to
         change fonts and you want to use this feature, enable this
         setting. However, with this setting enabled, your screen may
         lose characters and the cursor may change size and position
         slightly.

Default: DOSEDIT, CED

Purpose: Specifies which terminate-and-stay-resident (TSR) programs

         work properly if they are copied to each instance of a
         virtual machine. When you start Windows, it detects any TSR
         programs that are currently running. If the TSR is on the
         LocalTSRs list, Windows copies the TSR to each virtual
         machine you run. Many TSRs will not run properly if they are
         added to this list. Make sure your TSR is fully compatible
         with Windows and can be copied to a virtual machine before
         adding it to the list.

Default: 1 if an MS-DOS mouse driver is loaded that has the extension

         .COM or .SYS and supports the use of a mouse with a non-
         Windows application. Otherwise, the default is 0.

         Windows application in a window. Mouse support for a non-
         Windows application running in a window is automatically
         available if you are using a Windows 3.1 version of the
         grabbers. If you are using a Windows 3.0 version of the
         grabbers and you want mouse support, enable this setting. If
         you do not want mouse support, disable this setting.

Default: 0, unless an application is running that supports the

         use of the Task Switcher API by the NetBIOS.

         (running in standard mode) after it has made an asynchronous
         network BIOS call. If this setting is disabled, you cannot
         switch away. Switching away from some applications that make
         these calls might cause your system to fail. Once Windows
         detects an asynchronous NetBIOS call, you cannot switch away
         from the application, even if no more of these calls are
         made. Enable this setting only if you are sure that the
         applications you use will not receive network messages while
         they are inactive.

Default: 25

Purpose: Specifies the number of lines that will be displayed on the

         screen when you run a non-Windows application. An application
         that specifies a different screen mode can override this
         setting.

Default: The directory that the TEMP environment variable points to;

         if there is no TEMP variable, the default is the root
         directory of your first hard drive (usually labeled C:). If
         you do not have a hard disk, the default is the root
         directory of your first floppy disk drive (usually labeled
         A:).

         which Windows running in standard mode swaps non-Windows
         applications.

[standard] Section Settings

The [standard] section contains settings that are specific to running Windows in standard mode.

The [standard] section can contain the following settings.

FasterModeSwitch=<0-or-1>

Default: 0

Purpose: Enabling this setting causes Windows running in standard mode

         to use a faster method of switching from protected to real
         mode on many 80286-based computers. When this setting is
         enabled, Windows responds quicker to hardware interrupts,
         allowing better throughput for interrupt-intensive
         applications, such as communications applications. In
         addition, you should enable this setting if you are using a
         Zenith Z-248 system and are losing characters while typing,
         or if you are using an Olivetti M-250-E and lose mouse
         functionality.

Int28Filter=<number>

Default: 10

Purpose: Specifies the interval of INT28h interrupts, generated when

         the system is idle, that are made visible (or reflected) to
         software that is loaded before Windows. Windows will reflect
         every nth interrupt, where n is the value of this setting.
         For example, a value of 1 reflects every INT28h interrupt, a
         value of 2 reflects every second INT28h interrupt, and so on.
         Increasing this value might improve Windows performance, but
         may interfere with some memory-resident programs, such as
         network software. Set this value to 0 to prevent any INT28h
         interrupts from being reflected. Setting this value too low
         (from 1 to 9) might interfere with communications
         applications.

Default: 8

Purpose: Specifies the size (in kilobytes) of the data-transfer buffer

         that Windows running in standard mode allocates in
         conventional memory for transferring data over a network. If
         an application is not running correctly, your network may
         require a larger buffer than the default value. Increasing
         this value will decrease the amount of memory available to
         applications. If no network software is running, this setting
         will be ignored and no memory will be allocated.

[386Enh] Section Settings

The [386Enh] section contains information specific to running Windows in 386 enhanced mode, including information used for virtual-memory page swapping.

The [386Enh] section can contain the following settings.

AllVMsExclusive=<Boolean>

Default: False

Purpose: If enabled, this setting forces all applications to run in

         exclusive full-screen mode, overriding all contrary settings
         in the applications' program information files (PIFs).
         Enabling this setting might prolong the length of the Windows
         session when you are running network and memory-resident
         software that is incompatible with Windows.

Default: 2

Purpose: Specifies the amount of time (in milliseconds) to allow a

         virtual machine to process a COM interrupt. If, while running
         a communications application, you lose keyboard characters on
         the screen, you can try increasing this value.

Default: False

Purpose: If enabled, the Virtual COM Driver (VCD) uses its own copy of

         the interrupt handler for the serial communications driver.
         This improves performance of your COM ports. Enable this
         setting if you are using a Windows version 3.0 serial
         communications driver. Disable this setting if you are using
         the standard Windows 3.1 serial communications driver.

Default: True

Purpose: Specifies whether the FIFO buffer of a COM port's 16550

         Universal Asynchronous Receiver Transmitter (UART) should be
         enabled (True) or disabled (False). If a serial port does not
         have a 16550 UART, this setting is ignored.

COMIrqSharing=<Boolean>

Default: True for Micro Channel and EISA machines; False for all other

         machines.

         multiple serial ports or with other devices. Enable this
         setting if your machine uses the same interrupt for COM3 or
         COM4 as it does for COM1 or COM2.

Default: Yes

Purpose: If this setting is enabled, when you start the MS-DOS prompt

         a message box appears with instructions on how to exit and
         switch away from the MS-DOS prompt. Disable this setting if
         you do not want to see the message.

Default: See "Purpose" below.

Purpose: Normally, when running in 386 enhanced mode, the memory

         between B000:0000 and B7FF:000F is used by the general system
         unless a secondary display is detected. Enable this setting
         if you are using a VGA-based color display and want
         EMM386.EXE to include this address space as an upper memory
         block (UMB). In addition to enabling this setting, you must
         include the i= option in the device=EMM386.EXE command line
         in your CONFIG.SYS file as follows:

            device=EMM386.EXE i=B000-B7FF

EMMExclude=<paragraph-range>

Default: None

Purpose: Specifies a range of memory that Windows will not scan to

         find unused address space. This has the side effect of
         turning off the RAM and ROM search code for the range. The
         range (two paragraph values separated by a hyphen) must be
         between A000 and EFFF. This scanning can interfere with some
         adapters that use the same memory area. The starting value is
         rounded down and the ending value is rounded up to a multiple
         of 16K. For example, you could set EMMExclude=C800-CFFF to
         prevent Windows from scanning the addresses C800:0000 through
         CFFF:000F. You can specify more than one range by including
         more than one EMMExclude line.

Default: None

Purpose: Specifies a range of memory that Windows will treat as unused

         address space regardless of what may be there. EMMInclude
         takes precedence over EMMExclude if you specify ranges that
         overlap. The range (two values separated by a hyphen) must be
         between A000 and EFFF. The starting value is rounded down and
         the ending value is rounded up to a multiple of 16K. For
         example, you could set EMMInclude=C800-CFFF to ensure that
         Windows can use the addresses C800:0000 through CFFF:000F.
         You may specify more than one range by including more than
         one EMMInclude line.

Default: None

Purpose: Specifies the starting paragraph where the 64K page frame

         will begin when Windows (running in 386 enhanced mode) cannot
         find a suitable page frame. Allows an EMM page frame in an
         area containing some unused RAM or ROM. For example, you
         could set EMMPageFrame=C400 to start the page frame at
         C400:0000.

Default: 65536

Purpose: Specifies the total amount of memory available for mapping as

         expanded memory. The default value allocates the maximum
         possible amount of system memory as expanded memory. Specify
         a value for this setting if you run an application that
         allocates all of the available expanded memory. If this is
         the case, you cannot create new virtual machines. If this
         value is zero, no expanded memory is allocated, but the EMM
         driver will load. To disable EMM and prevent the EMM driver
         from loading, use the NoEMMDriver setting.

Default: Off in 386 enhanced mode; not supported in standard mode.

Purpose: Indicates whether File Manager automatically receives

         messages anytime a non-Windows application creates, renames,
         or deletes a file. If this setting is disabled, a virtual
         machine can run exclusively, even if it modifies files.
         Enabling this setting can slow down system performance
         significantly.

Default: No

Purpose: If enabled, prevents Windows from running other applications

         when memory-resident software has the InDOS flag set.
         Enabling this setting is necessary if the memory-resident
         software needs to be in a critical section to do operations
         off an INT21 hook, but will slow down system performance
         slightly.

Default: True

Purpose: Specifies whether a critical section is needed to handle

         INT28h interrupts used by memory-resident software. Some
         networks do internal task switching on INT28h interrupts.
         These interrupts might lock up some network software,
         indicating the need for an INT28h critical section. If you
         are not using such software, you might improve Windows task
         switching by disabling this setting.

Default: On

Purpose: Specifies whether you can press CTRL+ALT+DEL to quit

         applications that cause an unrecoverable error in 386
         enhanced mode. If this setting is enabled, you can quit the
         applications without restarting Windows. If this setting is
         disabled, pressing CTRL+ALT+DEL will restart your entire
         system.

Default: 4

Purpose: Specifies the maximum number of COM ports supported in 386

         enhanced mode. Change this value if you have more than four
         COM ports installed in your computer.

Default: False

Purpose: If this setting is enabled, Windows attempts to save a

         failing NetBIOS request. When an application issues an
         asynchronous NetBIOS request, Windows attempts to allocate
         space in its global network buffer to receive the data. If
         there is insufficient space in the global buffer, Windows
         typically fails the NetBIOS request. If this setting is
         enabled, Windows attempts to save such a request by
         allocating a buffer in local memory and preventing any other
         virtual machines from running until the data is received or
         the timeout period (specified by the NetAsynchTimeout
         setting) expires.

Default: 5.0

Purpose: Specifies the timeout period (in seconds) when Windows will

         enter a critical section in order to service an asynchronous
         NetBIOS request. It is used only when the NetAsynchFallback
         setting is enabled. This value can include a decimal (such as
         0.5).

Default: 32 on Micro Channel machines (IBM PS/2 or compatible); 0 on

         non-Micro Channel machines (IBM PC/AT or compatible).

         transport software if a network has been installed. In this
         case, the buffer size is the larger of this value or the
         value of DMABufferSize.

Default: 12

Purpose: Specifies the size (in kilobytes) of the data-transfer

         buffers in conventional memory that Windows allocates for
         transferring data over a network when running in 386 enhanced
         mode. All values are rounded up to the nearest 4K.

Default: None (Setup assigns an appropriate value based on your system

         configuration.)

         386 enhanced mode.

Default: 2

Purpose: Specifies the amount of additional memory, in 16-byte

         increments, that Windows should reserve in each successive
         virtual machine when the UniqueDOSPSP setting is enabled. The
         setting that works best for your machine might vary depending
         on your memory configuration and the applications you are
         running. Valid values are 2 through 64. See the UniqueDosPSP
         setting for more information.

Default: False

Purpose: Indicates whether Windows should consume or reflect DOS INT

         2A signals. The default means Windows will consume these
         signals and therefore run more efficiently. Enable this
         setting if you are running memory-resident software that
         relies on detecting INT2A messages.

Default: True

Purpose: If this setting is enabled, Windows periodically synchronizes

         its time with the computer's CMOS clock. If this setting is
         disabled, Windows usually maintains the correct time, unless
         TrapTimerPorts is disabled and you are running applications
         that can cause the system time to run faster or slower than
         the actual time. This setting is related to the
         TrapTimerPorts setting.

Default: 0

Purpose: Instructs Windows to go into a critical section around all

         timer interrupt code and specifies a timeout period (in
         milliseconds). Specifying a positive value causes only one
         virtual machine at a time to receive timer interrupts. Some
         networks and other global memory-resident software may fail
         unless this setting is used. However, using this setting
         slows down performance and can make the system seem to stop
         for short periods of time.

Default: True

Purpose: Specifies whether Windows should trap read and write

         operations to the system timer ports that are performed by
         applications. If this setting is disabled, Windows will not
         trap these operations, allowing applications that frequently
         read or write to the timer to run faster. However, this may
         interfere with ability of Windows to keep accurate system
         time. If this setting is disabled, Windows can usually detect
         when an application has changed the timer interrupt interval
         and then make any adjustments to the time. If your system's
         time appears to be running fast or slow, enable this setting.
         If you do not want to enable this setting, enable the
         SyncTime setting. This causes Windows to check the time
         periodically and then make any necessary adjustments.

Default: True if you are running a network based on Microsoft Network

         or LAN Manager. See the NETWORKS.WRI online document to find
         out whether the network you are running is one of these.
         False for all other networks.

         at a unique address (PSP). Each time Windows creates a new
         virtual machine to start a new application, Windows reserves
         a unique amount of memory (i bytes) below the application.
         For example, if the first application is loaded at address M,
         the second application is loaded at address M+i, the third at
         M+2i, and so on. The amount of memory (i) is determined by
         the PSPIncrement setting. These settings ensure that
         applications in different virtual machines all start at
         different addresses. Some networks use applications' load
         addresses to identify the different processes that are using
         the network. Disabling this setting on such networks might
         cause one application to fail when you quit another, because
         the network interprets them as the same application. When
         this setting is enabled, slightly less memory is available
         for non-Windows applications.

Default: On for AT-compatible computers; Off for all other computers.

Purpose: If enabled, Windows in 386 enhanced mode can terminate

         interrupts from the hard disk controller, bypassing the ROM
         routine that handles these interrupts. Some hard disk drives
         might require this setting to be disabled in order for
         interrupts to be processed correctly. If this setting is
         disabled, the ROM routine handles the interrupts, which slows
         down system performance.