USB Partitions on Windows

Here Is a couple of links that will help.

Partition a USB-Stick - Microsoft Answers

Partition USB Flash Drives

When splitting up a flash drive here only the first will appear in Windows Explorer regardless of the file system as far as Fat 16/32, NTFS, or exFat the new form of FAT. You'll notice on one of those pages there for the Lexar tool that a separate partitioning program would be needed.

One guide for paritioning a usb flash card, memory card, also flash drives along with a download link for the Lezar tool is seen at How to Partition a USB Flash Card | eHow.com

One old SF thread is how I made up data recovery sticks out of flash drives being split into a large NTFS front end data partition with a second root partition where a Linux distro is installed. That goes into using GParted necessary for the other OS when parting out the flash drive. Using the "Other OS" For a USB Rescue Device?

I tried the Lexar tool at one time back when the 7 RCs were out and it wasn't practical splitting up a flash drive to begin with since most will go with a smaller then 16gb model. Natively Windows will only see the first partition whether primary or extended even when NTFS is the file system used on multiple partitions.

For splitting anything up generally that would be left to a large capacity hard drive like a 1tb or larger to allow enough drive space. Even there you are limited to 4 primary type partitions while you can see numerous extended volumes.

As for data recovery sticks those will only see two partitions with the second for the other OS's root/file system partition without any swap partition needed for the purpose of a fast live boot to retrieve from a Windows machine when Windows won't even boot into safe mode. You won't use up a lot of memory since you wouldn't be installing programs on the other OS to begin with.

As for booting other OSs programs like Portable VirtualBox allows you to run other OSs once you unpack the program files onto the flash drive and run it from there. When writing a iso to flash drive the program used should be able to make the flash drive bootable as well as write the disk image to the removable drive itself in order to boot live from it when selected from the boot device menu.

GParted is the drive tool used for this since it is versatile being a cross platform partitioning tool for projects like a custom install of the other OS onto a root partition. The warning when creating this type of live usb stick when seen done on a Windows machine is outlined in the old thread there about seeing the root made the "/ mount point" and selecting the flash drive as well as the first NTFS data partition as the place for the Grub loader to be installed to avoid trashing the Windows mbr on the host machine.

Even on a 32gb flash drive only one root partition for only one distro was the idea seeing a 4gb to meet the minimum for various distros while only one was to see a direct install. ubuntu was squeezed onto a 16gb model with the 2.25gb root being the first distro while other larger distros see a 4gb.

This is why the idea is best tried out on the larger capacity models. If you have 300gb of data on a drive you will obviously want the rest of the flash drive reserved for a single first data partition. 24-25gb approximae on a 32gb model.

For splitting up a flash drive in order to run multiple live distros that will prove to be a different project entirely for the other OS. You would need a common swap partition(extended) and a separate root(ext 2, 3, or 4 file journaling system for Linux) which would be unavailable to Windows.

This is why one distro in particular Linux Mint Debian is being looked over since that is supposed to be able to install onto an NTFS volume. Of course that had to be put on hold for trying out on the second OS drive here due to the Windows 8 RP needing a drive to go onto. If I decide against dual booting 7 with 8 later then the drive will be available for giving that idea a lookover.

For a flash drive split up like you want to try out there the installer for each would need to be pointed at each separate root partition(usually an extended volume) and share the same swap as well as boot loader in order to see that work. The EasyBCD program does offer support for some distros like ubuntu but not for others when trying to add a boot entry in just to let you know since that would be the better boot editing tool while many opt for the wubi loader.

I'll throw out another option. But, alas it would have some cost involved. I use this solution my self and it works rather neatly.

Zalman ZM-VE200 (can be had at around $38.00)

Zalman ZM-VE200 HDD enclosure

With that you will need a 2 1/2 drive (I used a 500MB) The price for this will vary according to size and brand.
I load iso's on to this and carry it from computer to computer and boot to multiple configs. Such as Linux, Ubuntu, Win PE, etc. It eliminates CD Rom and Usb sticks. All in one device. I have had good success with it. Just something to think about.

500mb or 500gb? There's a large difference. If you are going to run how many distros? at 4-8gb a primary root(not necessarily a primary type but extended) partition for each plus a shared swap(2-4gb optimum) total all that up plus how large you want the data partition to be in order to get an idea on the size of flash drive or even preferred external hard drive or hard drive in usb enclosure.

10 times 4gb is 10 distros on 4gb roots at 40gb. Then add a 10gb data partition along with a good one or two swap partitions to come in at the need for a 64gb flash drive. Those typically run about $150- for the top brands while prices for them are now dropping sharply below $100.

A year ago $50 for a 32gb while newegg saw the same for $64- approx. now sees $50 for a Kingston DT 64gb model. Time for me to start shopping for a larger data recovery stick!

Typo! I have several Iso loaded onto it (It requires the iso you boot from to be loaded in ?:\iso directory. I use the rest for various files that I can carry with me. Some files are portable exe that I use for trouble shooting (Such as portable apps).
It's never let me down. Sorry for the misstatement in size.

You are mounting the iso directly on virtual optical drive rather then seeing a direct install to flash drive. That could be done as well with the Portable VirtualBox. I tried the 7 RC out as well on a flash drive back in 2009. How To Install Windows 7 On USB Flash Drive