Why not?

With a proper BIOS PC or CSM enabled, you can partition a SSD for a few MBR-layout partitions, then format the first partition FAT32. Following partitions can be formatted NTFS.

Windows 98SE can then be installed to the volume if your BIOS can enable ATA mode (for HDD access to complete the boot process), otherwise you still can manually install the plain DOS (which underlies W98SE itself) to the FAT32 volume, but that way you only boot to the bare metal command line.

DOS is simple enough where the BIOS or CSM can transparently handle access to the ATA, SATA, or USB drives, keyboards and mice without drivers or anything. Sound is not so easy though.

DOS will usually work with the full amount of modern memory still physically installed, but W9x not, so excess memory might need to be disabled in BIOS or physically removed beforehand for full W9x use.

If you have a (empty) WINDOWS folder already on your FAT32 DOS volume before you try to install W9x (or WXP) on it, then you will be given the option of putting the new install into a differently named folder if you wish, I would choose for a WIND98 folder rather than WIN98 since the latter was almost like a keyword.

To a fresh FAT32 DOS volume without any of its few files in actual folders (directories) at that point, when you installed W98 it created your first 3 folders; Documents and Settings, Program Files, and your main Windows OS folder (which was either the default WINDOWS or your chosen alternative such as WIND98).

When you upgraded from DOS to W9x the bootsector no longer loaded simply IO.SYS, but WINBOOT.SYS then which brought in the whole Windows GUI on top of DOS.

As mentioned WXP can also be installed to a FAT32 volume, works great but it was never a mainstream approach. You can search much faster when its a FAT32 volume.

XP install CDs usually also need to use ATA mode rather than SATA (AHCI) mode in the BIOS unless the proper SATA drivers have been slipstreamed into the ISO.

Maybe this Delta edition handles that well.

If you install XP to your FAT32/DOS/W9x volume which still contains your (intentionally empty) folder named WINDOWS, you will again be given the option to choose an alternative OS foldername such as WINXP. The WINXP choice was the actual XP default at the very beginning (W2k used WINNT foldername just like NT3 & NT4) before reverting to WINDOWS foldername for most XP PCs and newer.

This would not be a recommended approach for users who were not comfortable renaming an existing Program Files folder used by Win9x to something else such as Prog98, otherwise installing XP over W9x would overwrite a number of the default Windows 98 programs in the Program Files folder with NT versions. Better to just hide the W9x Program folder and let XP write a whole new Program Files folder for itself when it installs. Either Windows version then boots using just its own uniquely named Windows folder. W9x doesn't care if the Program Files folder is from a newer version of Windows, it will still boot. When booted to W9x some of the common programs in the XP Program Files folder will only run under NT and you will get an error for that, but to workaround you could set a shortcut to your renamed Prog98 folder in that case.

This NT install also overwrites the DOS volume bootsector so upon bootup it searches for NTLDR rather than DOS bootfiles, but it also makes a backup of your DOS bootsector first saving it as c:\bootsect.dos so if you want to you could use your new NTLDR to still boot to DOS or W98 if present (since it's FAT32 anyway) by adding the line c:\="DOS from W98" to your boot.ini text file. In boot.ini "c:\=" syntax in this case is shorthand for "c:\bootsect.dos=". Quite convenient and un-necessarily deceptive at the same time.

IOW for advanced MBR operators who want to sometimes boot to Linux from a Windows-formatted volume using the NT bootloader, you need to back up the NT bootsector (disk editor is good for this), prepare a Linux bootsector using GRUB or Syslinux then save it as a file named something like c:\bootsect.lin. Then you can replace the NT bootsector to the volume from backup. Then in your boot.ini add a line such as c:\bootsect.lin="Linux on type 83 partition 4" for instance.

Anyway with DOS, W9x and Wxp in the FAT32 bare metal root, WIND98 folder, and WINXP folder respectively, sharing the same FAT32 volume you could ideally choose any one of them (even further choose Linux or Windows installs on different partitions/filesystems if you went there) from the regular Windows NT multiboot menu which will appear upon PC startup.

It has also been seen that on an NTFS volume already containing W10, if the Windows 10 Program Files folder was renamed to something like Prog10 beforehand, XP could still be installed afterward to a folder other than WINDOWS and share the same volume as long as the HDD was set up using MBR layout rather than GPT and you have a good BIOS or CSM, with SATA or plain ATA handled accordingly. Carefully, W10 can also be booted from the NTLDR bootmenu if you had saved a copy of the W10 NTFS bootsector as a file such as c:\bootsect.nt6 beforehand. Then address that in your boot.ini. Which you would need the W10 bootsector backup file anyway normally, to restore to the partition (after XP has "downgraded" it) so you can go back to using the original W10 NT6 BOOTMGR instead of the older NTLDR from XP. You then have to manually add an NTLDR bootentry to the modern NT6 BOOTMGR bootmenu to boot XP from there.

But that's kind of backwards, ideally things like Vista, W7, W8, W10 & W11 would each be installed on their own remaining NTFS partitions without sharing the volume with any other OS. As each of these OS's is installed to its partition on an MBR-layout HDD it writes its additional bootentry to the NT6 bootmenu within the standard BOOT folder on your "Active" MBR partition, typically the FAT32 volume on your first partition which is often small in drive space and considered reserved for boot files alone. Alternatively, as we have seen, regular DOS can easily format as much as a 32GB FAT32 volume so there can be plenty of room for things like DOS, W9x, or Wxp to be also installed and function right there beside the active boot files. And the boot files can access other partitions too.

With a BOOT folder this beefy, and NTLDR in the mix you may now have DOS, W9x, NT5, NT6 and even Linux on the bare metal at your fingertips.

Next adding a new similarly beefy EFI folder to the FAT32 volume will provide an additional, alternative way to boot the same OS's on the same partitions, but on non-BIOS PCs only the OS's modern enough to support UEFI booting will be available (for booting) when a proper CSM is not enabled.

UEFI alone is supposed to support booting from either MBR or GPT layout on the HDD, as long as a readable useful EFI folder is on a recognizable FAT32 volume.

When not using a BIOS or CSM, UEFI can't really boot into DOS, W9x or Wxp any more, but when they are on the bare metal anyway you can still use them in a VM inside a modern OS, from right where they are if you do it right.