The only way for a direct install to an external usb drive I could see is if the drive also saw the eSata option where you can patch directly to the board where the Windows installer will then see the drive as an internal and can be accessed through the board's sata controller. Once Windows is installed you simply plug it back into a usb port since the drive is already bootable.
But once the installation is complete, all references to HDD will be via 'sata-controller'.
When plugged into usb port, the finished installation knows nothing about usb, only sata HDD.
This might not work.
If you look at the boot order or boot device menu on many boards under hard drives an external HD or flash drive will be an option to select. The board has to see that option however in order to boot from usb devices.
Right.
My board puts the SD, flash-drive, and USB HDD under "Disk drives", along with the "internal" HDD.
The guy doing the work here is the BIOS program.
I suspect he would also recognize the: MMC/SM/MS/MS-Pro/xD and the CF/Microdrive and put them in the same list.
But I don't have any of those chips to 'make bootable', so I'll never know.
Even if you get Windows on a usb drive or device the problem of still going through the usb bus and not having direct access to hardwares simply makes for a "vanity install" and not any fully functional Windows where you can install the device drivers for everything and see things work as you would with a normal installation to an internal or eSata connected drive.
You may be under a misconception here.
The function of the external device is to put the OS into core.
The device, whether internal or external makes no difference.
SD card, "internal HDD", flash-drive, e-sata, floppy disk, or even a teletype paper-tape reader can be the source.
Once in core, the OS has direct access to all hardwares.
In this respect, there is no such thing as a "vanity install" and it is a "booted-up" fully-functional Windows "installation".
If the "input" device is
writable (and big enough and fast enough), it is then also an "output" device.
You can install Device drivers, Office 2012, ShootemUp, Killum, UltraIso, or anything you want.
But not to the paper-tape reader.
Don't know what "OS" is involved here (if any at all), but the "loader" is mentioned.
The History of Microsoft - 1975 | The History of Microsoft | Channel 9.
It allows you to look over one version or edition while having another as the host OS.
There can only be
one boss OS (at a given time), in charge of running applications such as:
virtual emulators, Firefox 3.0, TV recording, wireless, email, IE8, or any other user app.
Of course, at
another_given time, there could be another, different,
boss OS in charge.
This would be an extremely fine example of time-slicing, but I don't think
any MS OS would cooperate with that...
(Here come the slings and arrows...)