From DSL Wiki
For some older or otherwise unique computer systems, it is not possible to boot up DSL directly from the livecd CD-R disk or from a USB pendrive.
- For the CD-R disk, some computer BIOS do not support booting from a CDROM drive or they cannot boot from a non-standard CDROM drive like a parallel port drive or a pcmcia CDROM drive.
- For the USB pendrive, most computers that were manufactured before 2001 have an older BIOS that does not support direct booting from a USB device.
However, it is still possible to boot up DSL if you make the right boot floppy disk.
First, go to the DSL download site  and download the appropriate floppy image file:
If you are already using linux, you can easily create the boot floppy disk with this command:
dd if=bootfloppy.img of=/dev/fd0
However, if you are using Windows, please download and unzip the RawWrite for Windows bootfloppy creation program here:
And then open the rawwrite.exe file (in the location that you unzipped) to select the bootfloppy.img file and create a boot floppy disk. Make sure that you have the formatted floppy disk inserted because the creation will begin suddenly with no confirmations.
If your boot floppy does not work, try using a different or newer floppy disk. Even a single bad sector on a floppy disk can prevent DSL from booting up.
Once you have your boot floppy working, the following command is required at the boot prompt in order to boot the USB pendrive:
To boot from CD, the command is :
You may append whatever additional cheat codes you wish.
Alternative Poorman's Install
Finally, if your CDROM drive is still not found by DSL upon bootup and you are using DOS/Windows 95/98/98SE/Windows ME, it is still possible to use DSL.
First, boot up with your old operating system.
Second, insert the DSL livecd disk.
Third, copy the \KNOPPIX\KNOPPIX file over to C:\KNOPPIX\KNOPPIX
NOTE THAT YOU SHOULD USE ALL CAPITAL LETTERS FOR THE DIR NAME AND FILE NAME
Fourth, reboot your computer using the DSL boot floppy.
It should find the "KNOPPIX" file on your hard drive and boot into DSL. This is known as a "Poorman's Install" of DSL to your hard drive with boot floppy.
Note that this will probably not work with Windows NT/2000/XP, since they use the NTFS file system on the hard disk.
Note that if you intend to actually install DSL as Debian onto your harddrive for releases after and including 2.0, you should also copy the \boot\ tree to C:\boot\ (with older versions of DSL, copy \KNOPPIX\boot\ tree to C:\KNOPPIX\boot\ instead), as the harddrive installation process attempts to copy the kernel off of the 'CD'. Versions 1.5 and older only require the additional \KNOPPIX\boot.img to be copied to C:\KNOPPIX\boot.img, but why would you be using an older version of DSL anyway?
See also: USB Booting.