How to make a boot-disk for MS-DOS 6.22

Hello WinWorld

I have downloaded your DOS 6.22 with CD support, extracted all files and everything is fine. I now want to make a bootable CD or USB.

Is this possible, please?


  • AFAIK, MS-DOS was not made to boot from optical disk (CD/DVD) or USB (except MS-DOS 7.1, which does work on CD), it's only for floppy disks. Floppy disks were what people used back in the 80's and early 90's for installing media on computers. Optical disks were not fully mainstream until about 1993 or 94, when operating systems, software, and other computer media started being sold on CD. So with that said, you already have the installation media extracted from your 7z file, but it's in the IMG format, the disk image file format used for floppy images, and it's most likely bootable.

  • I don't know. But if you try making MSCDEX and making floppy boot work in CD Boot, it might work. Sorry i am doing good at Lua, not how DOS is made (it might be assembly)

  • Actually in both cases making bootable image is trivial: you just embed your floppy image into larger CD or USB image. Use mkisofs -b option for that (other programs would surely support other options) and RMPrepUSB for USB.

    What's tricky - is to provide support for the USB and CD itself! Because by default BIOS would just emulate that mini-floppy for you... and that's it. Your MS DOS would boot perfectly fine... except it wouldn't see the CD and/or USB it just booted from!

  • Um, DOS is not "made" for booting from USB devices either. Although any BIOS that can make a USB drive look like a floppy or hard drive may work.

    Making a bootable CD is not too hard really. I use ImgBurn that is posted here on Winworld. Just go in to its options and tell it to make a bootable CD, give it a 1.44mb or 2.88mb DOS image and the CD it writes should boot to that image. The main catch is you won't be able to see the rest of the CD unless the image loads the DOS CD driver for your machine and MSCDEX. While generic IDE drivers will work on most IDE machines, many machines will need different CD drivers. SATA CD drives will have to run in IDE emulation mode. If you need to experiment with the image, use rewritable CD-RW media.

  • There's some funky grub stuff out there that can mount a floppy image on usb to ram and boot dos from it. It would then do emulation of the usb drive to enable some sort of r/w.
    I used to use that in my microdrives as an emergency boot disk when I was too cheap to go buy a newfangled (and smaller capacity) usb flash drive for the purpose, and I was trying to get rid of floppies. Set my d2x to mass storage mode, plug it in, and profit.

    I still use that thing as an oversized usb drive, but at least it can take pictures!

  • to make a bootable CD I use ultra iso and back in the the day of dos computers I would
    use the sys command to put a boot on floppys I am not sure if you can use that command on a usb!

  • You could store all the files on their and DOS could probably figure out which is which...

  • All versions of DOS, including 7.1 and later, can not boot from a cdrom. The trick is to create a bootable floppy diskette, and set it to load the cdrom. For this to happen, you need to create a 1440 image, with a proper DOS bootsector, etc.

    Put in the boot files IBMBIO.COM and IBMDOS.COM (or IO.SYS and MSDOS.SYS for MSDOS), or IO.SYS and JO.SYS for Dos95. Then COMMAND.COM. You can put a range of local utilities, like fdisk, format. You can use a cdrom loader, eg eltorito.sys, or the like, which hooks up the cdrom through the boot chain.

    Use some sort of utility like XMSDSK to make the ramdrive, and set the ramdrive to R: and the cdrom to S:

    Lay the hard disk so it has an ISO format, and you can install all different versions of DOS on the same disk. An MS-DOS boot sector on the floppy can be used to install MS-DOS 5 to 6.22, as well as windows etc.

    When it comes time to cut the image, tell the proggie that your BOOTDSK is the boot disk of the day. You can have several boot images, and pick them from a menu.

    The idea behind the ramdrive is to make things quicker. A 4 Meg ramdrive should suit most needs.

    With Dos98 (ie 98/98SE/ME), JO.SYS is a proggie that provides the 'do you want the cdrom boot' before heading off to the hard drive. Some menu programs do this too, so if you're doing it by menu, you don't need JO.SYS there.
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