Probbably some of you have the same annoying problem.
I often have to boot under DOS in order to perform some maintenance things - re-format or re-partition hard disk, do virus diagnostics or recover files.
I love using fdisk, or McAfee viruscan in command line mode. I love typing "fdisk". For that, MS-DOS command line is nice.
Booting from a flashdisk is faster than floppies, and a flashdisk a lots more space than a floppy.
So, now, how to boot from a flashdisk without complicating or dangerous things ?
Here is the way I do it. Of course, I found the trick from several places on the Internet, but nobody gave the step-by-step I needed, that's why I wrote my own one, here it is.
My own USB flashdisk is a Cosk*in 2gb, from http://www.cosk-in.com
First of all, let's see if your PC is able to boot from a flashdisk.
Let's first power off your PC (correctly shutting down Linux or Crosoft Windows)

1. Testing the hardware.
Insert your USB flashdisk in a USB port, and power on your PC. Then, go to the BIOS SETUP menu (usually it's F2).
Then look at the "BOOT" section. Depending on your BIOS version, have a look at the first boot device, it can be seen as a removable device or a hard disk. Of course, before changing anything here, you must carefully write down the initial settings in order to be able to come back in case of trouble.
If the BIOS sees your flashdisk as a removable device, choose it as first boot device.
If your flashdisk is seen as a disk, you have to put this disk as first disk.

Save your settings and exit.

2) Making the flashdisk bootable.
Now, go to a very old computer running windows 98. I know, sometimes it's rather hard to find one. Personnally, I used a vmware virtual machine on my brand new PC.
When you are on your Windows 98 or Windows Millenium system, download the drivers for your USB flashdisk. This will probably need a reboot.
As soon as your flashdisk drivers are installed, you will be able to see your flashdisk files using Microsoft Windows Explorer. Remember the name of the concerned disk. Let's let's suppose that your USB disk drive name is "U:"
Then, open a command prompt windows (for instance click Run --> Execute --> command)
At the DOS command prompt, type :

This "sys u:" command transfers on your USB flashdisk the system files needed for booting your flashdisk, exactly like it would do it on any standard disk. One of this files you probably already know, it's the well-known "command.com" file.
The other files are IO.SYS and MSDOS.SYS

That's all. You made your flashdisk bootable. And you already know it's harmless, because you simply added some files to your flashdisk. If you want to go back, simply remove these files.

Now the most interesting thing :

3) Boot from the flashdisk.

Everything is setup. While your system is powered down, insert your USB flashdisk in any free port, and power on your pc.
After a couple of seconds you will see the popular C> prompt. You may type VER in order to verify the version.
That's all you can do at that point. But if you inserted some more files (like format.com or fdisk.com) you have a working ms-dos system.
Further you may add mouse.com, or probably and autoexec.bat or and/or a config.sys file.



4) Discussion.
I love this method because it's simple and harmless. You do almost nothing special on your flashdisk, you just add a couple of files.
I used some other more sophisticated tools from the internet, they started by a flashdisk reformat (and I lost all my favourite files) and then they did not work.
That's why I love this way using an old win95 system and just type "sys U:"

A couple of interesting, related links on this topic:

http://articles.techrepublic.com.com/5100-6346-5928902.html

http://www.oreillynet.com/pub/wlg/5735

http://www.pendrivelinux.com/

http://www.techarp.com/showarticle.aspx?artno=431

http://rz-obrian.rz.uni-karlsruhe.de/knoppix-usb/

Don't forget DSL (Damn Small Linux) if you're working with a smaller thumbdrive. Tha base system is around 50 megs with addon packages available.

Hey, can I install an OS on my flashdrive and make it boot? I have 2gb flashdrive maybe I can install Win98 on it..just for experimental.

i booted from damn small linux from my jump drive once
damn small linux is pretty pointless really no offence to anyone hear who likes it

Meh, personally I prefer to install an OS properly than to try and use a removable version (such a Live CDs with Linux). I never have more than one OS on a computer at a time, simply because I'm not a great fan of the way in which they do things differently. Sure, they'll probably work fine, but anyway...

Ideally, I get a full OS (namely not DSL) and have it on my computer straight after a format. I like to keep it tidy, so knowing that I don't have lots of little files that might intefere with each other (even if they don't intend to) isn't a nice thought.

So, I know that under Windows you can format a floppy disk as a system disk. I thought you could also format a USB drive as a system drive under windows on the format menu, but I'm not sure. It won't copy many useful utilities, but you can grab the ones you want from the Windows menu on your computer and add them.

~Viz

You should be able to load some form of OS on your flash drive then load from it, theres nothing suggesting why it shouldn't work.

Has anyone ever tried loading an OS onto a DVD-RAM disk? From what I know, if you have the right drive then you can write and read to this disk constantly, so it should work to load an OS onto, right?

Puppy Linux does that. It works fully in memoy for performance purposes, but writes down it's things to be saved on a next session of the CD. It does this with regular CD, so no need for a DVD-RAM device.

Check for the portable Win Xp on torrent. Its just 60MB!!!!!!!!!!!!!!!!