I don't often need to do this, but once in a while it's handy to boot to a MSDOS boot floppy (either 6.22 or 7.00) from a machine that has PXE support.

Here's the pxelinux.cfg menu entry that will boot either a DOS or Win 98 SE boot floppy image:

default syslinux/menu.c32
prompt 0

MENU TITLE MS-DOS/Windows Installer Menu
menu separator

LABEL DOS - MS-DOS 6.22 Setup Floppy i386/amd64
KERNEL syslinux/memdisk
APPEND initrd=dos/MS-DOS_6.22_Disk_1_Setup.IMA
TEXT HELP
Boot MS-DOS from DOS 6.22 setup floppy image. NO FAT32 large disk support.
ENDTEXT

LABEL DOS - MS-Windows 98 SE Floppy i386/amd64
KERNEL syslinux/memdisk
APPEND initrd=dos/Windows98_SE.img
TEXT HELP
Boot MS-DOS from a Windows 98 SE floppy image. With FAT32 support for large disks.
ENDTEXT

LABEL Return
MENU LABEL ^Return to Main Menu
KERNEL menu.c32
APPEND pxelinux.cfg/default

You need the following files:

• memdisk - Part of the syslinux distribution (find it inside /usr/lib/syslinux/)
• menu.c32 - Part of the syslinux distribution
• MS-DOS_6.22_Disk_1_Setup.IMA - MSDOS 6.22 boot floppy, https://www.bootdisk.com/.
• Windows98_SE.img - Win98SE boot floppy (DOS mode), sourced from https://www.bootdisk.com/.

This can be quite a handy setup for systems without a floppy drive, or those that need to boot to a DOS prompt in order to flash a BIOS or similar.