System Startup Files

This section describes the following files involved in Windows 98 system startup:

• Io.sys, the real-mode operating system that replaces the MS-DOS version; VMM32 and Windows 98 device drivers take control from Io.sys.
• Msdos.sys, which contains special information for Windows 98, is also created. This gives compatibility with applications that require Msdos.sys to be present before they can be installed.
• Config.sys and Autoexec.bat.
• System.ini and Win.ini.
• Bootlog.txt, the log file that describes the system startup processes.

Table 5.5 summarizes how Setup renames the system files from the previous operating system when Windows 98 is installed. (The Windows 98 files are renamed with .W40 file name extensions when you start the computer with the other operating system.)

Table 5.5 Setup system file naming

Io.sys: The Real-mode Operating System

In Windows 98, the Io.sys system file replaces the MS-DOS system files Io.sys and Msdos.sys. This real-mode operating system file contains the information needed to start the computer. Your computer no longer needs Config.sys and Autoexec.bat to start the Windows 98 operating system (although these files are preserved for backward compatibility with certain applications and drivers).

Note

The Windows 98 Io.sys file is automatically renamed to Winboot.sys if you start the computer using your previous operating system.

The drivers loaded by default in Io.sys include the following files, if they are found on the hard disk:

• Himem.sys
• Ifshlp.sys
• Setver.exe
• Dblspace.bin or Drvspace.bin if Dlbspace.ini or Drvspace.ini exists in the root of the boot drive.

Most of the common functionality provided by the various Config.sys file entries in older operating systems is provided in Io.sys. Table 5.6 lists the common entries from Config.sys that are incorporated into Io.sys for Windows 98.

Table 5.6 Config.sys settings incorporated into Windows 98 Io.sys

To override default values in Windows 98 Io.sys

• Place an entry in Config.sys with the value you want.

The values in Io.sys cannot be edited. If Config.sys contains switches or other parameters for any of the drivers or settings created by Io.sys, the Config.sys entries override the Io.sys defaults. Entries for files=, buffers=, and stacks= must be set in Config.sys to at least the default values in Io.sys.

Note

Io.sys does not load Emm386.exe. If any of your applications requires expanded memory or loads data into the high memory area, EMM386 must be loaded in Config.sys.

Msdos.sys: Special Startup Values

Windows 98 Setup creates a hidden, read-only system file named Msdos.sys in the root of the computer’s boot drive. This file contains important paths used to locate other Windows files, including the registry. Msdos.sys also supports an [Options] section, which you can add to tailor the startup process.

The following example shows a typical file with default values:

[Options]
BootGUI=1

[Paths]
WinDir=C:\WINDOWS
WinBootDir=C:\WINDOWS
HostWinBootDrv=C

Most values in the [Options] section are Boolean — that is, the value can be 1 (enabled) or 0 (disabled). Table 5.7 describes entries in Msdos.sys, using the typical default values.

Table 5.7 Msdos.sys entries

Config.sys and Autoexec.bat

For Windows 95 and Windows 98, the content and method for handling Config.sys and Autoexec.bat during system startup have changed. Windows 98 automatically loads drivers and sets defaults by using Io.sys, the registry, and other mechanisms, rather than Config.sys and Autoexec.bat.

Computers that require certain real-mode drivers or TSRs, however, will continue to require that software be loaded from these configuration files. Also, Config.sys and Autoexec.bat might be required to enable certain software options. Some options, such as long command lines, can also be enabled by using the Command.com program properties, as shown in the following illustration.

Config.sys Processing

Config.sys defaults are implemented by Io.sys, as described in the previous section. However, Config.sys can contain application-specific entries in addition to information stored in Io.sys. These are processed in the sequence they are listed. After the base Config.sys file has been read, all devices are loaded, and Command.com is started.

Windows 98 loads memory managers supplied by other vendors if they are present in Config.sys; however, some might cause errors. Similarly, Windows 98 allows the use of command shells from other vendors, but there are some differences. For example, long file names are disabled, which might also indicate that other problems could occur using these command shells.

Config.sys Changes for Windows 98

Windows 98 has predefined settings built in for most common Config.sys settings, so Windows 98 Setup removes many of these lines (such as settings for files, buffers, and stacks) if they are equivalent to the default values, by using rem to comment out the line.

Autoexec.bat Processing

Autoexec.bat is not required for Windows 95 or Windows 98, but it is included for compatibility purposes. If the computer has an Autoexec.bat file, each line is processed in sequence during system startup. Autoexec.bat can contain additional application-specific entries that are run in the sequence they are listed.

Windows 98 passes the initial environment to Command.com with the correct Windows and Windows Command directories already in the path and with the environment variables PROMPT, TMP, and TEMP already set. (TEMP= and TMP= indicate locations for temporary directories; both are specified for compatibility reasons.)

Table 5.8 describes the Autoexec.bat commands that have equivalent default settings created in Io.sys for Windows 98.

Table 5.8 Autoexec.bat equivalents for Windows 98 Io.sys default settings

The default Windows 98 environment includes the following:

tmp=c:\windows\temp
temp=c:\windows\temp
prompt=$p$g
path=c:\windows;c:\windows\command
comspec=c:\windows\command\Command.com

Autoexec.bat Changes for Windows 98

Windows 98 Setup makes the following basic changes to Autoexec.bat:

• Updates the path= line statement.
• Uses rem to comment out incompatible TSRs.
• Deletes any win statement (or equivalent) and Share.exe.
• Copies the original Autoexec.bat to Autoexec.dos.
• Sets the Temp directory.

System.ini and Win.ini

This section describes changes related to system startup made by Windows 98 Setup to System.ini and Win.ini. Mappings for other changes between Windows 3.1x and Windows 98 are described in Chapter 31, "Windows 98 Registry."

System.ini Changes for Windows 98

Table 5.9 lists configuration options that have been added to System.ini, deleted, or moved to the registry. Most of these options for Windows 98 are now stored in the registry and are no longer required in System.ini.

Table 5.9 Changes made to System.ini entries in Windows 98

Set the related parameters using Windows 98 tools as follows:

• Set all memory-related parameters by using the System option in Control Panel. For information, see Chapter 26, "Performance Tuning."
• Set parameters for hardware devices by using Device Manager in the System option in Control Panel. For information, see Chapter 24, "Device Management."

Win.ini Changes for Windows 98

Table 5.10 shows how the font and desktop information in Win.ini is transferred to the registry in Windows 98.

Table 5.10 Changes made to Win.ini entries in Windows 98

In addition, Setup always adds ATMWorkaround=1 to the [Pscript.Drv] section in Win.ini.

Set the related parameters using Windows 98 tools as follows:

• Set all mouse parameters by using the Mouse option in Control Panel. For information, see Chapter 24, "Device Management."
• Set parameters for the keyboard by using the Keyboard option in Control Panel. For information, see Help.
• Set all screen and window display parameters by using the Display option in Control Panel. For information, see Chapter 24, "Device Management."

Bootlog.txt: The Startup Process Log

The Bootlog.txt file contains a record of the current startup process for starting Windows 98. This file is created during Setup when the Windows 98 operating system is first started from Windows 98 Setup. This file shows the Windows 98 components and drivers loaded and initialized, and the status of each.

When you use the F8 option for interactive system startup, you can choose to create a boot log during system startup. You can also use the /b switch to create a boot log when running Win.com from the command line to isolate configuration problems. For information, see Chapter 27, "General Troubleshooting."

The information in Bootlog.txt is written in sequence during startup, in roughly five major sections. Depending upon a specific error condition, you might need to examine multiple sections. Notice, however, that a loadfailed= entry means only that the related VxD refused to load. For example, loadfailed=ebios indicates that the EBIOS driver did not detect EBIOS in the computer and so reported that it should not be loaded. Table 5.11 shows the sections to examine and describes the possible errors and methods for correcting those errors.

Table 5.11 Bootlog.txt sections for determining errors

Table 5.12 shows the kinds of entries in Bootlog.txt to examine for information about the system startup process.

Table 5.12 Bootlog.txt entries to examine for system startup

For example, if you see an entry such as DynamicInitDevice=PPPMAC but there is no matching entry such as DynamicInitSuccess=PPPMAC, that VxD failed to load. If a driver in the Windows System\Iosubsys directory stalls when it is being initialized, you can sometimes successfully start the system by renaming that file.

The following shows a sample Bootlog.txt file:

Loading Device = C:\WINDOWS\HIMEM.SYS
LoadSuccess    = C:\WINDOWS\HIMEM.SYS
Loading Device = C:\WINDOWS\EMM386.EXE
LoadSuccess    = C:\WINDOWS\EMM386.EXE
Loading Device = C:\WINDOWS\SETVER.EXE
LoadSuccess    = C:\WINDOWS\SETVER.EXE
Loading Device = C:\WINDOWS\COMMAND\ANSI.SYS
LoadSuccess    = C:\WINDOWS\COMMAND\ANSI.SYS
Loading Device = C:\WINDOWS\IFSHLP.SYS
LoadSuccess    = C:\WINDOWS\IFSHLP.SYS
Loading Vxd = VMM
LoadSuccess = VMM
Loading Vxd = nwlink.vxd
LoadSuccess = nwlink.vxd
Loading Vxd = vnetsup.vxd
LoadSuccess = vnetsup.vxd