General configuration notes for DOS, W98SE, and ISA-era BIOS

Hard Disk Mode (Auto, Normal/CHS, LBA, or Large)

Some of the memory tweaks appear on this page for some reason.

XX000-XXFFF Shadow (Enable or Disable)

AGP-2X Mode (MPV3)
AGP-4X Mode (KT133A)

SDRAM Cycle Length (2 or 3) (MVP3 & KT133A)
SDRAM(CAS Lat/RAS-to-CAS) (2/2 or 3/3) (430TX)

DRAM Timing (SDRAM 10ns, SDRAM 8ns, Normal, Medium, Fast, or Turbo) (MPV3)
Bank X/(X+1) DRAM Timing (SDRAM 8/10ns, Normal, Medium, Fast, or Turbo) (KT133A)

MD Driving Strength (KT133A)

Other more or less obscure speedup options available on this page seem to be mostly harmless.  Some in the 1999 versions clearly apply only to 72-pin SIMMs.

PNP OS Installed

Resources Controlled By

Assign IRQ For USB

Onboard Serial Port 1/2 and Parallel Port

IDE Prefetch Mode and HDD Block Mode

Yes:  The BIOS will initialize mainboard devices, PCI and AGP cards but not ISA PnP cards.

No:  The BIOS will also attempt to initialize ISA PnP cards.  This is a desperate way to maybe get a PnP card to work when you have no drivers for it.

Disable unneeded serial and parallel ports to free up three IRQs and one DMA.

IRQ 3/4/5/7/10/11 (Available or Reserved)

Shared PCI IRQs (Auto, Share One IRQ, Share Two IRQs, or Share Three IRQs)

USB legacy emulation (a BIOS feature) is necessary for a USB mouse or keyboard to be visible in plain DOS (not yet tested:  USBDOS driver), W98 Safe Mode, and the early stages of W98 installation.

The BIOS may try to be "smart" about when to enable the emulation.  Example:  EeePC 1000, booting DOS through LILO, enables legacy emulation for the touchpad.  However, if the first bootloader is Grub2 and it chainloads LILO to boot DOS, the touchpad doesn't work.

If the motherboard has just one PS/2 port that supports either keyboard or mouse, let the mouse have it.  Legacy emulation is more likely to work right for the keyboard.

N.B., PCI cards that add PS/2 ports don't work without drivers.

I'm currently using W98SE FDISK to get partitions that work with everything (i.e., no complaints from FreeDOS, W98, or LILO).  Sometimes both that and the FreeDOS FDISK will crash on launch and there is no choice but to use Linux fdisk.

FreeDOS's FORMAT will sometimes crash when attempting to save unformat information.  To avoid this, do FORMAT /S /Q /U C: (optionally adding /V:DOS to specify the volume label).  The /Q /U combo means "Quick formats the disk but does NOT preserve unformat data and does NOT wipe or scan the surface.  Just deletes everything FAST.  This is the default if an unformatted harddisk is detected."

I use a software package known as "the Ellis drivers" or just "drivers."  As of the 2022-07-01 release, these are the relevant programs:

• XMGR.SYS is an extended memory manager (XMM) that replaces bloated HIMEM.SYS and plays nice with UMBPCI.
• XHDD.SYS is a disk cache + Ultra DMA (UDMA) accelerator.
• XDVD2.SYS is a CD/DVD-ROM device driver.

Since 2003, this collection of drivers has changed form many times without significant changes to function.  The drivers have been revised, updated, deleted, re-added, merged, split, renamed, refactored, open-sourced, closed-sourced, plagiarized, and embargoed.  See archaeological dig of Ellis drivers for a complete history and links to the current software.

I did most of my sound card testing using the 2015-03-05 release, in which UIDE.SYS provided the combined functions of XHDD.SYS and XDVD2.SYS in one driver.  Since then I have updated to new releases without systematically retesting to determine whether compatibility or performance had changed.

Option 1:  Virtual 8086 mode with VCPI

DEVICE=C:\LOCAL\DRIVERS\XMGR.SYS /B /N24  ; Temporary "boot"
DEVICE=C:\LOCAL\JEMM\JEMM386.EXE NOEMS I=B000-B7FF X=B800-CBFF I=CC00-E7FF X=E800-FFFF
DEVICEHIGH=C:\LOCAL\DRIVERS\XMGR.SYS
DOS=HIGH,UMB

Option 2:  Real mode with XMS, HMA, and UMBs

DEVICE=C:\LOCAL\UMBPCI\UMBPCI.SYS
DEVICE=C:\LOCAL\DRIVERS\XMGR.SYS /W
DOS=HIGH,UMB

Option 3:  Real mode with XMS and HMA

DEVICE=C:\LOCAL\DRIVERS\XMGR.SYS
DOS=HIGH

Notes

Starting (aggressive) configuration as of Drivers release 2022-07-01:

DEVLOAD /H C:\LOCAL\DRIVERS\XHDD.SYS /S128 /H /O
DEVLOAD /H C:\LOCAL\DRIVERS\XDVD2.SYS /H

The default DVD-ROM device name is UDVD1.

Fallback configurations:

1. On some PCs, loading the UDMA driver into UMBs provided by UMBPCI results in spontaneous reboots or lockups when protected-mode games are run.  If that happens, remove /H from DEVLOAD.
2. When used in combination with many sound cards, UDMA results in lockups.  If that happens, replace XHDD /O with /E (use BIOS calls).  If DVD-ROM access causes lockups, add /UX to XDVD2 (disable UDMA and force PIO mode).
3. If neither of those helps, omit XHDD entirely.  XDVD2 then runs without a cache.

An alternative to XDVD2 is available as a JEMM Loadable Module (JLM).  It uses only XMS memory and does not cache.

DEVICE=C:\LOCAL\JEMM\JLOAD.EXE C:\LOCAL\JEMM\XCDROM32.DLL /D:UDVD1

FreeDOS:

SHELLHIGH=C:\COMMAND.COM C:\ /E:2048 /P
BUFFERSHIGH=30
FILESHIGH=40
STACKSHIGH=9,256
LASTDRIVEHIGH=E
IDLEHALT=1

MS-DOS:

SHELL=C:\COMMAND.COM C:\ /E:2048 /P
BUFFERSHIGH=30
FCBSHIGH=4
FILESHIGH=40
STACKSHIGH=9,256
LASTDRIVEHIGH=E

Jason Hood's SHSUCDX

LH C:\LOCAL\BIN\SHSUCDX.COM /C /D:UDVD1

DOSLFNMS is the one that worked.  Cautions:

1. Some versions were horribly broken.  I stayed on version 0.41c for a long time.  Now I am using 0.41f.  The maintainer and upstream site keep changing.
2. Disk caching (as is provided by XHDD) is essential to avoid a major slowdown.

LH C:\LOCAL\DOSLFN\DOSLFNMS.COM

CTMOUSE works with all normal serial and PS/2 mice and never conflicts with anything.  Version 2.1 beta4 seems to be the de facto stable release.

LH C:\LOCAL\BIN\CTMOUSE.EXE

For FreeDOS, just put IDLEHALT=1 in CONFIG.SYS.  For MS-DOS, FDAPM served the purpose.

LH C:\LOCAL\BIN\FDAPM.COM APMDOS

Untested alternative:  EIDL

For specific sound card details, see ISA or PCI.

To avoid unnecessary splash screens and logs, install the following in the root directory as MSDOS.SYS:

[Options]
SystemReg=0
DisableLog=1
Logo=0

Getting W98 working on a newer PC involves satisfying, working around, or patching its outdated assumptions about memory size, hard disk size, and hard disk access mode.  Binary patches for all of these issues that R. Loew sold commercially were released to the public after his death.  As yet I have not tried anything but the memory size patch.

• W98 is a single-CPU operating system.  Additional cores provide no benefit.  The last single-core CPUs in Intel's desktop category were the Prescott Pentium 4 series.  However, running on one core of a multi-core CPU does work.
• W98 has problems with more than 512 MiB of RAM and becomes unbootable at 1 GiB.  Workarounds are detailed in a following section.  Loew's PATCHMEM allows the OS to use larger amounts of RAM.
• W98 is unable to access anything beyond the 128 GiB limit of 28-bit LBA.  It can live in the first partition at the beginning of a larger disk as long as the partition table does not confuse it.  Loew's PATCH137 (alias PATCHATA) adds support for partitions up to 2 TiB (the MBR limit) while TBPLUS includes more infrastructure to support drives up to 32 TiB.  I have not tested either one.  Note also, 1TB "Patch to support Partitions Larger than 1TB" listed under unpackaged and prerelease software but missing from the archive.
• Often it is necessary to configure a SATA controller in BIOS for "Legacy Mode," "Compatible Mode," or "IDE" rather than "Native Mode," "Enhanced Mode," or "AHCI" in order to get through the W98 installation process.  Once installed, W98 may continue working if AHCI is re-enabled.  Loew provided AHCI and SATA drivers in the patchsets AHCI (missing), SATA, AHCICD, and TBPLUS.

Whenever W98 complains that it can't find a file and pops up a dialog box to let you locate it, the place to browse to is either the WIN98 directory of the installation CD or the directory from which you are trying to install something.  It will generally pick it up even though it's buried in a CAB file.

If maximum patching up is desired, there is an unofficial service pack maintained by PROBLEMCHYLD, or see the ostensibly complete list of hotfixes & updates for Windows 98SE on MSFN.  See also, tons of miscellaneous stuff from MDGx.  The following is my short list.

• IO.SYS from kb311561
• This unofficial hack of FDISK (kb263044) and FORMAT
• 4756US8.EXE = the Shutdown Supplement from kb239887
• 269601usa8.exe = the WDM audio update from kb242937

W98 must reside entirely within the first 128 GiB (137 GB) of the hard drive to avoid overflowing its 28-bit LBA implementation.  Setup is basically wack when it comes to large disks, so run FDISK and FORMAT manually before entering it.  Use the patched versions noted above and ignore any incorrectly printed sizes.

FDISK

• Enable large disk support.
• It scans the disk, very slowly.
• No, don't use the entire disk.
• It scans the disk again, even slower.
• Specify the partition size in MiB.  8192 (8 GiB) is a safe choice.
• Set the new partition as active and get out of there.

Various disk-trashing misbehaviors can occur if one does not walk on eggshells around W98 FDISK and FORMAT.  Repartitioning (as opposed to creating a new partition table) should always be done using Linux fdisk, never a Windows installation CD.  Windows will trash your partition table every time.

FORMAT /S /U C:

• W98 format is sensitive to the pre-existing contents of the target partition.  The /U switch reduces this sensitivity but the jury is still out on whether it is a complete solution.  If FORMAT crashes or only creates a 2 GiB file system (FAT16), either wipefs -a the partition, lay down a FAT32 format using Linux mkdosfs, or zero it out entirely and then retry.
• W98 format tends to crash if it is asked to quick-format (/Q) a file system that was created with mkdosfs.

After launching setup, just continue past the warnings about there already being an OS in the partition and about NT file system.  Any unrecognized partition type is assumed by setup to be NT.

When setup finishes its first phase, you are instructed to remove the floppy (meaning take the CD out) and reboot.  Setup has already clobbered the MBR, so when you reboot you enter the GUI portion of setup.  It is at this point that memory size hacks become necessary if 1 GiB or more of RAM is present.

Two reboots later, W98's hardware wizard is busy installing drivers.  You have to humor it until it goes away.  Even when it has no driver for a particular device, it must be allowed to search for it; if you just cancel out, the dialog will come back again every time you reboot.

W98 fails in a variety of ways when more than 512 MiB of RAM is installed.  Usually the error says "Insufficient memory" or "There is not enough memory available."

PATCHMEM

HIMEM workaround

DEVICE=C:\DRIVERS\XMGR.SYS

C:\XMSFIXER.COM

DEVICE=C:\HIMEMX.EXE /MAX=523264

SYSTEM.INI configurables

[386Enh]
MaxPhysPage=30000

[vcache]
MaxFileCache=131072

CPU idle driver AMNHLT (amnhltm.zip)

VIA chipset drivers

Maximus Decim Native USB drivers

DOS drivers for CD/DVD/BD, mouse, etc.

DEVICE=C:\XMGR.SYS
DEVICE=C:\XDVD2.SYS /H

SHELL=C:\COMMAND.COM C:\ /E:1024 /P
BUFFERS=20
FCBS=4
FILES=20
STACKS=9,256
LASTDRIVE=E
DOS=HIGH

C:\XMSFIXER.COM
C:\SHSUCDX.COM /C /D:UDVD1,D

Sound drivers can be either VxD or WDM.  Microsoft's GS softsynth only works with WDM drivers.  However, all WDM sound drivers cause glitching of sound effects in DOOM.  kb242937 does not fix that.

Commonly, the only mixer will be hidden underneath the Microsoft volume control in the bottom right corner of the screen:  single-click the tiny icon for volume, double-click it for the mixer.

For specific sound card details, see ISA or PCI.

If no good vendor drivers exist, W98's plain old "Standard PCI Graphics Adapter (VGA)" driver usually works.  However, it is limited to 640×480 16-color mode and is slow.  In my experience, it is reliable across a broad range of video cards, including older PCIe ones, but with a GTX 970 it produced glitched graphics.

The VBEMP 9x Universal VESA/VBE Video Display Driver (or here) works on a similar principle.  It too is slow, but unlike the Microsoft driver it allows access to high resolution, true color modes supported by the video BIOS.  It worked without glitching at 1920×1080 32 bpp on the GTX 970.  To install it, navigate through device manager or right click on desktop → Properties → Settings → Advanced → Adapter to the current display driver, choose Update Driver or Change, navigate some more through to "Have Disk" and "Browse," and browse to the 128MB directory of the VBEMP distribution.

Milestones in Nvidia Windows driver version history:

GPU "support" was determined from the release notes.  The User's Guide for 66.93 still claims support for Vanta, TNT, and TNT2.  Neither the release notes nor the users guides are correct—when tested, a TNT2 64 actually worked up through version 71.84!

Nvidia's official support for W98 ended with the GeForce 6 series GPUs.  Maximus-Decim's modded 82.69 drivers supposedly work some of the time up through the GeForce 9 series, but they didn't work for me.

When DOOM running in a DOS box tries to switch to full-screen 320×200 mode, Nvidia drivers often give a black screen (maybe just with LCD monitors?).  The standard VGA driver and the VBEMP VESA driver don't have that problem.

The 71.84 and 81.98 ForceWare drivers did not render 640×400 mode correctly for DOOM 95.  Versions 12.41, 53.04 and 66.94 all worked.

Image quality in 640×400 mode is improved by checking the box NVIDIA Display → Display Mode Timing → Enable doublescan for lower resolution modes (if it exists in the version used).

For some versions, EnableRefreshRateLock.reg is needed to enable setting a non-default refresh rate that will stick within games.

As described here and here, most installation prompts can be pre-configured using a batch tool that is provided on the W98 installation CD (under tools\reskit\batch).  Burn the resulting msbatch.inf file into the WIN98 subdirectory of the installation CD and most prompts go away.  It still has a few nits:

• Does not auto-accept license agreement
• Does not skip name and company screen
• Still puts useless junk on the desktop
• Still autoruns the task scheduler

To get rid of the task scheduler, run msconfig, select Startup tab, uncheck Scheduling Agent, reboot.

The W98 install CD's boot image has this in CONFIG.SYS for both the SETUP_CD and CD menu options, which makes for a slow and messy boot:

device=himem.sys /testmem:off
device=oakcdrom.sys /D:oemcd001 
device=btdosm.sys 
device=flashpt.sys
device=btcdrom.sys /D:oemcd001
device=aspi2dos.sys
device=aspi8dos.sys
device=aspi4dos.sys
device=aspi8u2.sys
device=aspicd.sys /D:oemcd001

Replace that with this:

DEVICE=XMGR.SYS
DEVICE=XDVD2.SYS /H /D:oemcd001

And in AUTOEXEC.BAT:

REM LH MSCDEX.EXE /D:oemcd001 /L:D
REM We haven't loaded any UMB provider, so LH is useless.
SHSUCDX.COM /C /D:oemcd001 /L:D

This only affects the environment for Setup.

Dropping the patched FORMAT.COM and FDISK.EXE into the WIN98 subdirectory of the installation CD apparently causes these versions to be installed automatically.

TBD:  CAB edits to reduce the amount of post-install patching that is required.

Using W98SE as a version of plain DOS is actually much easier than getting it to work in Windows mode.  DOS has no failures triggered by memory over 512 MiB and will use BIOS calls for disk access.

1. Prepare a partition and format it as described previously.
2. Manually copy in any desired binaries and set up AUTOEXEC.BAT and CONFIG.SYS to taste.

FreeDOS has a better installer and bundles superior, enthusiast-maintained replacements for many of the DOS programs that come with W98SE.  As a compromise, one can take the kernel, COMMAND.COM, FORMAT.COM, FDISK.EXE, and SYS.COM from W98SE for better MS-DOS compatibility, but throw out everything else and use free replacements.

If you installed Linux before W98, you will need the Linux install CD or an emergency boot something to get you back into Linux to reinstall LILO or GRUB after W98 does its damage.  Alternately, you can back up your MBR before installing W98 and then just restore it afterward.

Every version of Windows insists on owning the C: drive, so some workaround is always needed to get two Windows installations to coexist without jumbling their system files together in the same partition.  The easiest way to get XP and W98 to be good neighbors is to exploit the fact that W98 ignores NTFS partitions.  If you put XP on NTFS in the first partition and put W98 on FAT32 in the second partition, then each OS will see its own partition as the C: drive.  If for some reason this approach is unusable then you will have to fall back to more drastic options such as hiding and unhiding partitions or remapping drives at boot time.  N.B., even when the NTFS partition comes first, if XP is allowed to see W98's file system it will activate System Restore on it and create a subdirectory called System Volume Information in the root directory.  So while it is not strictly necessary to do so, you might want to hide the W98 partition just to keep the taint of XP off of it.

If you run Linux, it is generally easier and more reliable to boot W98 and/or XP using LILO or GRUB than using Microsoft's own boot loader.  LILO and GRUB support partition hiding and drive remapping if you should need those features.  On the other hand, the XP boot loader provides access to XP's safe mode.

The XP boot manager can be used to boot a W98 and/or Linux partition by following the example in the antiquated NT OS Loader + Linux mini-HOWTO (v1.11, 2 September 1997).  Copy Microsoft's boot sector (instead of a LILO boot sector as described in the HOWTO) from the W98 partition to a file on XP's C: drive and reference it in XP's BOOT.INI file:  C:\W98.BIN="Windows 98 SE".

Please note:

• The MBR installed by XP refuses to go if more than one partition is marked as bootable.  It prints the message "Invalid partition table" and halts.  This error is fixed simply by toggling the bootable flags so that only the XP partition is marked as bootable.
• The XP boot manager will only boot other operating systems if their boot sectors are copied to the C: drive.  It does not work to specify D: in boot.ini.

Nowadays, modern BIOSes include their own multiboot menus that are launched by hitting a hotkey during POST.  When things get out of hand, you can install a different boot manager on every disk and use the BIOS menu to choose among them.