Hi, William Torrez Corea wrote: > > I am using the following image: > > MS DOS 6.22 Bootable iso > > https://archive.org/details/ms-dos-6.22_dvd
Charles Curley quoted from there: > "If you need to burn it to a portable storage device, like USBs or > dvd disks, unfortunately it will not work." I downloaded https://archive.org/download/ms-dos-6.22_dvd/MS-DOS%206.22.iso and inspected it by xorriso -indev "MS-DOS 6.22.iso" \ -report_el_torito plain -report_system_area plain The image file is indeed an ISO 9660 filesystem with an El Torito boot catalog: El Torito images : N Pltf B Emul Ld_seg Hdpt Ldsiz LBA El Torito boot img : 1 BIOS y fd1.4 0x0000 0x06 1 26 El Torito img blks : 1 720 The boot image is an emulated floppy disc of 1440 KiB. So the ISO 9660 image is supposed to boot via legacy PC-BIOS from optical media: CD, DVD, BD. One could try to boot it by submitting the image as virtual CD-ROM to a virtual machine with SeaBIOS or alike (not OVMF). The files in the ISO bear dates from 1994, whereas the root directory and the PVD timestamps say that the ISO image was made in 2005. So it is questionable whether the software in the ISO is able to cope with contemporary real hardware. ----------------------------------------------------------------------- I see another unplausible statement in the description: "This is a portable MS-DOS ISO file. In case your machine does not support a BIOS for some reason, this will be very helpful." No BIOS = no booting via El Torito. The author obviously meant something else. Maybe there have been BIOS implementations which only booted from floppy disks, real and emulated, but not from no-emulation boot images (like Debian ISOs offer). Recently the german Linux Magazin re-published the first SuSE ISO which had no El Torito boot equipment but a bootable floppy image in it. The aspiring user was expected to copy the image out of the ISO filesystem onto a real floppy, which then could be used to boot the first stage and was able to use the CD-ROM with the ISO filesystem. Obviously the creator of the MS-DOS ISO did not expect that the boot image has to be put on a real floppy, or else the boot image would be a named file in the ISO 9660 filesystem tree. Have a nice day :) Thomas
