Disable System ROM Breakpoint:
This setting specifies whether Windows 98 should use Read Only Memory (ROM) address space between F000:0000 and 1 megabyte (MB) for a break point. Windows normally searches this address space to find a special instruction that is used as a system break point. If this address space contains something other than permanently available ROM, you should disable this setting. This sets "SystemROMBreakPoint=0" in the System.ini file. This is equivalent to starting Windows with the command-line switch "/d:s".
For additional information about SystemROMBreakPoint, please see the following article in the Microsoft Knowledge Base:
Article ID: 71264 (http://support.microsoft.com/kb/71264/EN-US/ )
TITLE : Information on SYSTEM.INI [386enh] Entry SystemROMBreakPoint=
Disable Virtual HD IRQ:
This setting prevents Windows 98 from terminating interrupts from the hard disk controller and bypassing the ROM routine that processes these interrupts. Some hard disk drives may require this setting to be enabled for interrupts to be processed correctly. If this setting is enabled, the ROM routine handles the interrupts, which can slow system performance. This sets "VirtualHDIRQ=0" in the System.ini file. This is equivalent to starting Windows with the command-line switch "/d:v".
EMM Exclude A000-FFFF:
This setting prevents Windows from trying to scan for unused memory address space. This also disables the Random Access Memory (RAM) and ROM search instructions for the memory address space. This scanning can interfere with some devices that use the same memory addresses. This sets "EMMExclude=a000-ffff" in the System.ini file. This is equivalent to starting Windows with the command-line switch "/d:x".
Force Compatibility Mode Disk Access:
This setting prevents all 32-bit disk drivers from being loaded except the floppy driver. You may want to enable this setting if your computer does not start due to disk peripheral input/output (I/O) problems. If you enable this setting, all I/O uses real-mode drivers or the basic input/output system (BIOS). Also, all disk drives that are functional in protected mode only, no longer function. This is equivalent to starting Windows with the command-line switch "/d:f".
For additional information about how to troubleshoot compatibility mode issues, click the article number below to view the article in the Microsoft Knowledge Base:
130179 (http://support.microsoft.com/kb/130179/EN-US/ ) Troubleshooting MS-DOS Compatibility Mode on Hard Disks
VGA 640 x 480 x 16:
This setting causes Windows 98 to use the standard VGA display adapter driver. This disables the existing "display.drv=" line of the System.ini file, and adds the "display.drv=vga.drv" line to the [boot] section of the System.ini file.
Use SCSI Double-Buffering:
Some Small Computer System Interface (SCSI) drives may require that this setting be enabled. Windows 98 should detect whether or not this setting is needed, so you should only enable this setting if there is a disk access problem. This adds the line "Doublebuffer=2" to the Msdos.sys file. This setting is unavailable if a Doublebuffer line already exists in the Msdos.sys file.
Disable Scandisk After Bad Shutdown:
This setting adds the line "Autoscan=0" to the Msdos.sys file. This can be useful when you troubleshoot shutdown issues, as it decreases startup time after a bad shutdown.
Limit Memory to
This setting limits memory usage on your computer to the first
Disable Fast Shutdown:
This setting disables Windows 98 shutdown performance enhancements. This can be useful to troubleshoot problems shutting down Windows 98.
Disable UDF File System:
This setting disables support for the Universal Disk Format (UDF) file system for all removable media. This setting can be used to troubleshoot problems with proprietary DVD players that may be incompatible with UDF.
Enable Pentium F0 (Lock CmpXchg):
This setting provides a method to work around an erratum in the Intel P5 series of processors (Pentium and Pentium MMX). The processor stops responding (hangs) if a particular illegal instruction sequence is issued. This issue should not occur with a normal program, it would have to be generated maliciously. If this setting is enabled, Windows 98 enables a protection routine to avoid hanging. This setting can interfere with some kernel mode applications (such as debuggers), so it should not be used while debugging programs.
NOTE: Norton Utilities 3.0 SpeedDisk and UnErase Wizard tools lock the computer if used with this setting enabled. If you have Norton Utilities, Microsoft recommends that you do not use this setting, or disable Norton Utilities from startup.